How to grow MICROGREENS at home -- Cleanly & Cheaply & Easily
♦ The shorter instructions and long list of seed sources for growing microgreens appear in the 2011 seventh printing of SPROUT GARDEN, but you have here also the definitive full-length instructions, either to download or printout from the PDF, or to read as text below (scroll toward the bottom of this webpage)
SOURCES listed in the clickable PDF (look to the right) include:
SPROUT SEEDS SUPPLIERS
NATURAL FOODS DISTRIBUTORS
GARDEN SEEDS SUPPLIERS
demonstrating growing and watering techniques (3MB PDF)
& EURO 50 cent coin for scale (1MB PDF)
click for 900 pixel high full view
ARRAY of 16 different microgreens
the red amaranth in right corner foreground really is as deep and as bright as the magenta in this photo
| click for 900 pixel high full view|
basil microgreens, 7 days
Be advised that all these greens were grown under ideal conditions:
BROCCOLI depicted here reached peak in 5 days, and BASIL in 7 days.
But your own mileage WILL vary, and during short days of winter can more than double.
BROCCOLI (1MB PDF)
Photos of SIX day cycle for BROCCOLI MICROGREENS, one photo for each day, a single pint container
BROCCOLI (1MB PDF)
Photos of SIX day cycle for BROCCOLI MICROGREENS, one photo for each day, a tray of 6 pint containers
BASIL (2MB PDF)
Photos of SEVEN day cycle for BASIL MICROGREENS, one photo for each day, a single half-pint container depicted during first 5 days, a tray of 6 half-pint containers depicted on 6th day, and close-up viewed from above depicted on 7th day
♦ Shorter instructions appear in the 2011 seventh printing of SPROUT GARDEN, but you have here the fuller 11,000 word version to read below
How to grow MICROGREENS at home
– cheaply, cleanly, and easily –
As we grow older, our newest foods are growing younger. Microgreens, the seedling stages of greens such as basil and broccoli, are even younger than mesclun salad greens. While farm-grown mescluns first appeared on our dinner plates in the 1980s, microgreens are even newer arrivals and an even younger stage of greens. The first use of the word microgreens was documented in 1998, so even the word itself is fresh. Long before we started calling them microgreens, farmers called them seedlings, and rabbits called them lunch.
Nutritional claims about these little leafies are boasted by food writers and microgreen growers, but in fact scant documentation exists about their nutritional benefits – that's how new they are. Instead, data on the nutritional value of microgreens are often interpreted from the scientific analyses that already exist about their forebears, called sprouts. While their vitamin content and mineral availability very likely decline when compared to the powerhouse in sprouts, microgreens do excel in regards to their phyto-nutrients and chlorophyll.
While home gardeners can grow microgreens on trays of soil and then can water them from above, my method described here ditches cumbersome trays that spill soil and drip water. Instead, here you use repurposed compact food containers that you place every one or two days into shallow pools of water, so that water is absorbed from below.
This technique of “bottom watering” is adapted from that employed by many commercial microgreen farmers who raise their crops in plastic containers that are manufactured specifically for growing seedlings. I owe my adaptation to Lauri Roberts of Farming Turtles, based in Exeter, RI. Lauri graciously guided me on a tour of her indoor microgreens farm, and showed me how to grow microgreens cheaply, cleanly, and easily.
You, too, can grow microgreens at home. Starting from the ground up, you will need:
♦ The CONTAINER
First, an apology. I apologize to all citizens of advanced civilizations that measure with the metric system. I apologize for the archaic use in the United States of the insufferably outdated English system of measurement, which even England has abandoned. Hence I apologize for my obscure references to pesky unit of measurement called the pint.
For the record: 1 pint equals approximately 500 mL. In practice, the metric equivalent of a pint container is not called 500 mL, but instead is called 500 grams, or half a kilo. Hence, 1 pint = a half kilo.
1) EAT LOTS of SMALL FRUITS
Small fruits such as blueberries, fresh figs, and tomatoes (tomatoes botanically are fruits, not veggies) usually are packaged in plastic pint (500mL, half kilo) containers. Raspberries and blackberries come packaged by the half-pint (250mL, quarter kilo), which are half the depth but also useful.
2) SAVE the PINT & HALF-PINT CONTAINERS
Rather than recycle or (gasp!) discard the containers, keep them. You likely eat mostly or only whole foods, so you soon will accumulate an abundance of plastic containers. The crucial features of these containers are the vents on their bottoms, and the lids on their tops. If necessary, rinse and dry them, then stack and store them.
The plastic is recycle number 1 (PET or PETE), a polyethylene polymer predominantly used for water and beverage bottles, collectively called drink bottles. When heated or during prolonged storage, PET can migrate into its liquid contents. Hence the plastic taste of bottled water. At moderate room temperatures and for short durations, however, PET does not affect its solid contents. Hence blueberries and cherry tomatoes do not taste of plastic. Moist soil might be considered semi-liquid, in which case purists might wish to avoid use of plastic.
Other containers with holes on their bottoms, for instance terracotta flower pots, are suitable, but they obstruct your view of the wondrous rootlets, and they are heavy, bulky, and costly. Commercially-produced pint-size plastic seedling pots are relatively inexpensive, and microgreen farmers deliver to restaurants their greens growing in soil in such pots. But for you to buy seedling pots might require a separate mail order or a special trip to a gardening store. Repurposed plastic food containers are near at hand in your favorite health food store and local supermarket, effectively coming to you. And they come to you for free, so are “good for nothing.”
Pint-size plastic seedling pots can be found in the produce section of many food stores after all – filled with hydroponics-grown broccoli microgreens (though usually called broccoli sprouts). Yet if you intended to hire someone else to be your microgreens gardener, you would not be reading this right now.
Repurposed plastic food containers do tend to fall apart after multiple re-uses, but you probably never will retain them that long. By attrition, you’ll be starting anew with a fresh batch of containers every three or four cycles. That’s because for every five or six containers that you grow, you likely will bestow one or two as gifts upon eager recipients.
Regardless how unwise their eating habits, all your friends will love your microgreens. Even the microgreens that might taste unappetizing, still look beautiful. And many people eat only with their eyes.
3) CUT OFF the LIDS of the PLASTIC CONTAINERS
Cut off all the lids and save half of them. These very useful lids actually are lacking from commercially-produced seedling pots, so you have another reason to repurpose plastic food containers. Designate an old pair of scissors for cutting off the lids, as the blades soon will become dull from this function. If your collection of containers originate from different manufacturers, one manufacturer’s lids might not snugly fit another manufacturer’s containers, so to assure matching pairs later, you might consider marking them now.
4) PLACE TWO CONTAINERS TOGETHER
Double up the containers, and place one inside the other. They fit best if matched by manufacturer, but even containers of different origin usually fit remarkably well. Doubling up assures rigidity of the entire container so that the soil does not shift and thereby disrupt the fragile rootlets anchored in it. Also, this protects the rootlets from being crushed on the bottom where they cluster. And third, this empty space on the bottom prevents water from pooling at the bottom of the soil, and this extra ventilation along the underside of the container prevents mold.
♦ The SOIL
The soil need not always be soil. Hydroponics, which supplies nourishment through highly mineralized water or liquid chemical fertilizer, utilizes other growing mediums such as natural fiber cloths and polyethylene foam pads. The resulting microgreens, however, can appear stunted or dwarfed, or look normal but taste bland. Further investigation and experimentation with hydroponics is warranted, but meanwhile be happy digging in the dirt. Just don’t call it dirt. Soil may be soiled, and earth certainly is earthy, but only dirt is dirty.
1) SELECT the SOIL
Potting soil and seedling mixes provide ample nourishment, but are not always “dirt cheap.” If instead you dig up soil from outdoors, you may introduce little creepy crawling critters into your kitchen as well as unwelcome weeds among your microgreens. Such risk is eliminated if you use commercial potting soils or seedling mixes, which have been sterilized. While sterilization is hardly natural, nevertheless here it is desirable.
Seedling mixes, also called growing mixes, enable the rootlets to gain footing faster than do potting soils, but may lack some nutrients. In practice, however, almost any seedling mix or potting soil will yield similar results. Be advised that seedling mixes are sold in large sizes such as bales only during the spring growing season, so plan accordingly.
Boosts to soil such as compost or liquid kelp or mineral dust or pulverized seashells often prove superfluous. Growth for one week is simply too short a duration to utilize fully these extra dosages of nutrition, which are akin to time-release pills. Such amendments to soil hasten growth of microgreens only slightly, if at all. Achieving the same results in one day fewer can be crucial for commercial growers, but need not concern you. A more important consideration which begs further research is whether potentially better nourished greens might better nourish you too.
2) SATURATE the SOIL
Before distributing the soil into the growing containers, place it into a bucket and stir water into the soil, fully moistening it. Remove any undesirable fibrous objects (UFOs) such as leaves or twigs or wood chips. Any abundance of wood chips is a sure sign of a poor quality potting soil. To avoid discovering this after you have lugged home the soil, feel for the presence of wood chips just under the surface of the bag, and do this when you are still at the gardening store.
3) CHOOSE either PINT or HALF-PINT CONTAINERS
While both container sizes will suffice regardless what seeds you plant, you should consider matching container depth to seedling. For root crops such as radish, rutabaga, turnip and beet, pint containers work better. For shallow-rooted seedlings such as lettuce and basil, half-pint containers are adequate. Broccoli and all the other related Brassicas do well in either. Half-pint containers with half the depth of soil as pint containers provide less bulk and less weight, whereas with twice the depth pint containers retain more moisture and so require less frequent watering.
4) FILL the CONTAINERS with MOISTENED SOILPress the soil firmly into the containers, and fill them right up to the brim. Fingers are fine, or use cardboard to flatten the surface of the soil. You might consider filling the bottom half of the containers with potting soil, and the top half with seedling mix. In time, you should experiment growing with all potting soil, with all seedling mix, with different layers or proportions of both, and with different sources for either. (Or with neither, and instead grow by hydroponics.) But for a start, half potting soil and half seedling mix offer the best of both worlds.
♦ The SEED
Any veggie that grows into sprouts in jars will continue to grow into microgreens on soil. Beans, however, as microgreens generally turn bitter. Grains as microgreens grow equally well on open trays of soil. So here we shall confine our discussion to the botanical classification strictly named seeds.
1) SEEK UNTREATED SEEDS
Mail order sources for gardening and farming seeds number in the hundreds, but only a handful offer untreated or organically-grown seeds in bulk quantities. More varieties of organically grown seeds are available now than compared to just a few years ago, so organic is certainly preferred. For conventionally grown seeds, verify that your source provides the option of untreated seeds. For purposes of microgreens, “untreated” and “bulk” are the winning criteria.
Gardening seeds are routinely treated with fungicides and sometimes insecticides. That poses little health risk if the seed starts small, if the plant grows big, and if the growing season stretches long. For microgreens, however, beware! (And even from untreated seeds, the plants and therefore the microgreens of nightshades are toxic. So do not seek seeds of tomatoes, eggplant, and peppers.)
Seeds sold specifically for growing sprouts or microgreens are untreated. But what about seeds grown for outdoor gardening? Unless the seed packet or catalog page states either organically-grown seeds or the option of untreated seeds, you should assume the seeds have been treated. If you have any doubts, when you place your order be sure to shout on the phone or write in big block letters: UNTREATED SEEDS ONLY!
Cost is also a consideration. Small packets suffice for gardeners tending a single row all season long in their backyards, but for microgreen folks that’s enough for only a single container for a one week cycle on a windowsill. So seek bulk quantities by the kilo or pound. That levels the planting field to few sources. Though not always organically grown, their seeds will expand your repertory into a preponderance of microgreens.
For a current listing of mail order sources of seeds for microgreens, consult the Sources chapter at the end of this book. The listing includes mail order sources for microgreen seeds from among gardening seeds companies that offer the option of untreated seeds, as well as from companies that specialize in sprouting seeds and in natural foods. These two latter sources offer only untreated seeds, so you need not stipulate that requirement to them.
2) SELECT SEEDS WISELY
The beginner gardener can find overwhelming the diversity of species from which to choose. If you would like to grow broccoli, you might consider omitting from your repertory many of the other family of Brassicas such as kale or cabbage. As microgreens, they are very similar. Broccoli grows quickly, tastes mild, and its seeds are widely available. Thus broccoli is a good Brassica starter seed for beginners.
Among the Brassicas, one whose microgreens taste better and look more beautiful than broccoli is the Chinese leafy green called bok choy, also spelled pac choi (Brassica rapa chinensis). Its seeds, however, are more expensive and less widely available than broccoli. Brassicas that outpace the rest of their family are the root crops radish and turnip, which grow faster than broccoli. If you’ve wondered how plants as diverse as kale and cauliflower, or broccoli and turnip, could belong to the same family, you’ll better understand upon viewing their seeds and their microgreens, which all look the same.
Outside the Brassica family, the many varieties of lettuce are good for beginners. The best tasting microgreen of all is basil, especially the variety deservedly called sweet basil, but basil requires warm temperatures and its seed is mucilaginous. A challenge to neophytes, it appears lower in the list of Top Ten. The second most outstanding (and upstanding!) microgreen outside the vast family of Brassicas is sunflower. Usually called sunflower greens without the prefix micro, sunflower microgreens thanks to its originator Viktoras Kulvinskas have been known to and grown by raw foodists long before the word microgreen was coined.
Here is a recommended Top Ten list EASY for beginners:
After you successfully have grown many of the above list, you may wish to accept greater challenges that do come with greater rewards. These next ten excel in the Department of Delicious, but require longer times for both germination and growth.
Ten More Microgreens Worth Your Special Care & Extra Effort
Dozens and sometimes hundreds of cultivars have been bred from among the many species of veggies. For instance, let’s examine the cultivar group Brassica oleracea, variation Italica, which in our vernacular is called Italian broccoli, and which most of us know simply as broccoli. (This excludes Romanesco broccoli, Chinese broccoli, broccoli raab, and broccoflower.) From three popular seed companies based in New England that offer some proportion of their seeds organically grown (OG), a buyer can choose from among 23 varieties just of broccoli. Additionally, the United States Department of Agriculture (USDA) Vegetable Laboratory lists 144 more, and this tally excludes all the continents outside of North America. Some of the more fanciful names of North American cultivars are Crusader, Excalibur, Hercules, Munchkin, Ninja, Pirate, and Samurai. From A to Z, the ascendant cultivar at the top on the list just happens to be named Apex, while paradoxically at the bottom of the list resides Zenith.
Prices vary widely, depending upon the variety. Some are dirt cheap, while some are almost worth their weight in gold, literally. The same species from the same seed company can cost twice the price, or more, for organically grown compared to conventionally grown. Thus some are measured and sold by the seed count, some by the gram, some by the ounce, and a rare few are sold in bulk by the half-pound, pound, half-kilo, or kilo.
Garden seeds intended specifically for growing as sprouts and microgreens are new to the marketplace. Their outstanding feature is bulk quantities at low prices. Before 1990, some hardy sprout folks were growing microgreens such as broccoli at home, but because seeds were so costly no one was marketing microgreens to the larger population of non-sprout folks. Nor was anyone calling them microgreens, because the word had not yet been coined. We should be thankful for the relatively new category of affordable seeds just for microgreens, without which this very discussion would not exist. For reasons of frugality, such seeds are sure to be selected from among the lower priced varieties sold in bulk. And they very likely contain mixtures of cultivars, and the mixtures very likely will vary from year to year.
What cultivar have you chosen? Most seed companies that sell broccoli marketed specifically for growing as sprouts or microgreens do not indicate their variety, but instead label theirs simply and generically “broccoli.” Your local health food store, too, seldom identifies its variety of broccoli, because neither does its wholesale distributor. Consequently, if you are especially fond of broccoli microgreens from seeds from one source, whether local store or a mail order, when you later replenish your supply from that same source you have scant assurance that it will be the same variety of broccoli of which you are so fond.
Solution? If you can afford their extra expense, purchase only those seeds whose cultivars are clearly identified. These will not be cheap, so from among the list of named cultivars of broccoli, select a small quantity of the least expensive one. Then hope for the best, meaning the best flavor. If your first crop proves second-rate, simply place another order, this time for the second cheapest one. And so on. Eventually you will find an cultivar that meets your expectations, if you live that long.
On the other hand, this entire discussion may be irrelevant, as you may never discern any difference among cultivars of broccoli when grown only to their incipient stage of sprouts or microgreens. Thus “generic” broccoli may be broccoli enough.
3) PURCHASE SEEDS in SMALL QUANTITIES
Small means enough for your supply to last only one year or less. Among Brassicas such as broccoli, and even then depending upon variety, when stored at room temperatures germination rates can drop as much as ten percent per year. Lettuce seeds fare far worse. Lettuce seeds will last as few as two years, and Brassicas as many as four years, before they no longer are worth sowing.
Beginning in late summer, some seed companies offer web-only special sale prices on seeds remaining from last year’s crop. Such discounts can prove substantial, and can provide an incentive to experiment with new seeds. But along with greatly reduced prices, expect slightly reduced viability. Seeds manifest life. Seeds are dearly precious, but also highly perishable.
Refrigerate seeds from the previous year’s crop as a precaution against loss of viability. Indeed, if you can spare room in your fridge, refrigerate all your seeds, especially during the hot summer months. The very moisture and warmth and air that are necessary for growth are antagonists to longevity. Glass jars better protect against moisture and air than do plastic bags. If you can smell from outside its contents inside, then you know the plastic bag is not airtight. But glass jars are only as airtight as the liners or gaskets along the perimeters of their metal or plastic caps, so seek a thick cap and a tight seal.
Label the contents. Along with storage, think signage. Identify the seeds, their source, and the date purchased. Remember, as we grow older, we forget more. But as we grow wiser, we more expect that we indeed will forget, and we plan accordingly.
4) MEASURE the SEEDS
The smaller the seed, the greater the number of seeds in a given volume, and so the smaller the measurement of seeds needed to cover a given area. For instance, if you intended to germinate, say, an avocado pit, you could fit only one single pit into a pint container. Here are some approximate measures for seeds per one pint (half kilo) container:
5) LAY the SEEDS EVENLY upon the SOIL
Allow ample “breathing” room between seeds, preferably not touching each other, and certainly not laying one atop another, which only wastes the seeds on top. Press them firmly into the soil, using either your fingers or the cardboard used earlier for flattening the surface of the soil. The tactile pleasure gotten from feeling both seeds and soil weigh heavily in favor of using only your fingers. Do not cover the seeds with soil, else a week later the succulent leaves will remain encrusted with dry earth.
Large seeds with thick hulls are exceptions. Do cover beet and chard with soil, so that their hulls get thoroughly moistened and are more likely to be cast off. Otherwise, you will need to manually remove many of the hulls from beet and chard.
Label the containers with the seed name, especially if you are starting seeds new to you along with several other varieties of seeds. Small labels used for return addresses on letters are the perfect size. Affix them high upon the plastic container, above the water line when you later will place them into a pool of water.
♦ The WATER
1) PONDER YOUR WATER
Water is a crucial component of indoor gardening, so there is much to ponder. The home gardener who experiments and compares different soils or different temperatures or different seeds seldom considers different sources of water. You might analyze its composition through laboratory analysis, or simply scrutinize its appearance with your eyes and nose, but still gain little insight in regards to your water’s suitability for your crops. Whether municipal tap water or bottled spring water or gathered rain water or pumped up well water or piped in pond water or melted down winter snow, water quality is best judged by its results.
Do a taste test. Conduct animal experiments, the animal being you. Prepare two containers filled with same soil planted with same seeds, and grow your microgreens under identical conditions of light and darkness and warmth, but not of water. Water one with your tap water, and another with spring or rain or well or pond or snow water. After one week, the two batches of microgreens likely will look the same, but do they taste the same?
Modify your tap water if your taste tests provide evidence for that. Chlorine is the predominate additive to municipal tap water that can affect your microgreens. Allow chlorinated tap water to stand in a wide-mouthed open container such as a bucket for a day, during which the chlorine will evaporate. Chlorine’s volatility accounts for the strong chlorine smell in enclosures around indoor swimming pools. Alternatively, activated carbon filters effectively trap chlorine. Filters compared to buckets are more immediate and therefore more convenient.
Be aware of chlorine’s alkalinity, in addition to chlorine’s toxicity. Chlorine is an alkali, and its dilution in water in turn affects water’s alkalinity. On the pH scale of 0 to 14 (not the archetypal 1 to 10), 0 to 6.9 are acidic with the low of 0 extremely acidic, 7 is neutral, and 7.1 to 14 are alkaline with the high of 14 extremely alkaline. Distilled water in a warm room at 77 degrees F. (25 C.) is neutral 7, but distilled water does not exist in nature, and temperature affects the pH of water. The additive chlorine renders water alkaline, notably between 7.1 and 8, which might inhibit germination of seeds. If your seeds routinely show slow or poor germination, or your seedlings tend to rot, then alkaline water may be the culprit, chlorine may be the source, and lemon juice can be the remedy.
Most edible greens thrive with water between slightly acidic 5.5 to neutral 7. Microgreens, as the early stages of greens, generally thrive with water between 6 and 6.5. If your water scores above 7, then you might consider lowering its pH.
Test your soil’s and water’s alkalinity or acidity with pH kits sold at gardening stores or mail order sources of hydroponics supplies. These come either with strips of litmus paper to dip into the water, or vials of liquid to mix with the water. Except for acid rain, overly acidic water is rare. Baking soda can neutralize acidity, but must be administered very sparingly. If test results show too much alkalinity, that is more safely remedied. Vinegar or lemon juice are household foods that are acidic, so adding very dilute amounts of either one will balance alkalinity. Lemon juice is preferred. Precisely how much to add depends upon the acidity of the lemon juice and the alkalinity of the water. Prudence dictates to start with less than a quarter teaspoon per gallon of water and test again, then if needed add another quarter teaspoon and test again.
Be aware that a homegrown pH test kit comes in the form of sprouting, as sprouts bathe in water. If their germination and growth meet your expectations, then you are “good to grow,” and you can dispense with any consideration of the pH of your water. This discussion after all warrants further investigation. Microgreens are very new foods about which we still have much to learn, so we must put all options on the table, including on the dinner table. Meanwhile it’s safe to say that if you do water with unfiltered chlorinated tap water, your little leafies still should flourish. The question to ponder is less about their survival, and more about their flavor.
2) SPRAY the SEEDS with WATER
The spray atop the seeds adds to and rounds out the moisture they soak up from the soil beneath them. Kitchen sink handheld spray nozzles potentially provide too intense a stream of water that can dislodge the seeds, so first set the faucet to a trickle. Spray bottles pose no such threat. Fine misters works best, but any spray bottle will do. A recycled spray container from a non-toxic household cleaner can be used if fully rinsed of residue. Taste the spray, to know for sure. Between crops, dismantle the spray container and allow it to dry out, else mold or bacteria can inhabit it. Everything, including mold and bacteria, wants to grow.
3) optional: PLACE MOIST COTTON CLOTH or PAPER TOWEL atop the SEEDS
As the seeds lay naked atop the soil rather than buried below it, the seeds dry out very quickly. Cloth or paper towel helps to retain moisture, so that you will need to spray only once a day. Choose undyed cotton cloth that is thin and smooth, such as for a bed sheet, not terry cloth such as for a bath towel. Or choose unbleached paper towel. Cut to size a piece to fit into the container. It need not cover all the seeds, which makes the towel all the easier to cut. Fully moisten it with water, and lay it atop the seeds.
Do not use such cloth, however, when starting mucilaginous seeds such as cress, chia, flax, arugula, and basil, else the seeds cling to the cloth above rather than to the soil below. For your first several crops, you likely will want to view the unfolding of the miracle of germination, so you may decide to postpone your use of the cloth.
Some folks choose to dispense with the cloth, and instead spray once or twice more daily. Those 2 or 3 sprays a day last only for the first 2 or 3 days, so hardly present an inconvenience.
4) COVER the CONTAINER with its LID
No need to snap on the snap-on lid. You can simply place it atop the containers, or snap on only one of its four corners. Removing and replacing the lid is much easier when you do not need to unsnap all four corners. If you did not already do so when you earlier cut off the lid, you might want to inscribe your lids and matching bottoms now, so that they will be easy to match up for your next cycle.
If you skip Step 3 and omit the moistened cloth, an alternative technique for retaining moisture comes in the form of an inverted cafeteria tray (also called fast food tray or serving tray). You very likely placed your group of pint containers upon a cafeteria tray, made usually of fiberglass. Take another matching tray, invert it, and place it atop the containers. This provides darkness, and also blocks some (but not most) of the vent holes in the lid. The vent holes in the lid allow ventilation. Ventilation prevents mold, but also allows evaporation. Too many holes means too much evaporation, so you simply are reducing the number of holes.
5) At least ONCE a DAY, LIFT the LID, and SPRAY
Lift the lid at least once daily to inspect the seeds. If the seeds look dry, then they are dry, so spray away.
Without the top cloth or a layer of soil atop the seeds, or cafeteria tray atop the containers, you’ll need to lift the lid and spray at least twice daily. While spraying as many as three times a day may seem a big bother now, this still is less bothersome than plucking off or rinsing away soil from leaves harvested later. If you do top off with cloth or paper towel, you need not remove the towel to spare onto the seeds, but can be lazy and spare onto the towel.
6) REMOVE the LID
When the sprouts reach the height of the lid, it’s time to set them free. Before they reach that height, you might consider unsnapping the lid and merely resting it on the container. Then when the sprouts reach the roof, they will lift up the lid and thereby provide you with a very clear sign to remove the lid altogether. In warm temperatures, broccoli hits the ceiling upon the second day, while slower grower basil will do so on the third or fourth day. Your mileage will vary.
7) PLACE the CONTAINER into a POOL of WATER
Gardeners call this bottom watering. Do this almost daily. Fill a basin or bowl with water approximately to half the height of the pint container. Keep the bowl in or next to your kitchen sink, and place the container of microgreens into the bowl. Allow it to sit there for half a minute to a minute, until the soil has become thoroughly moistened. Remove the container, set it at a slight angle inside the sink, and allow it to drain for a minute or more. Replenish the water into the bowl as needed, usually after every second container. Watering a tray of six containers as pictured in the photos takes five minutes, in between which you can tend to other matters in the kitchen.
The vent holes in the bottom of the plastic container prove their usefulness here. And here too is the advantage of this method compared to using messy and cumbersome cafeteria trays. I have grown wheatgrass and sunflower greens since 1977, and broccoli and an array of other Brassica microgreens on soil on cafeteria trays since 1993, so I speak from experience. The tray method is perfect for watering from above microgreens such as wheatgrass and sunflower greens, but none others.
(Ann Wigmore bestowed upon the world her gift of wheatgrass, and her protégé Viktoras Kulvinskas bestowed upon the world his gift of sunflower greens and buckwheat greens. But buckwheat as greens, also called buckwheat lettuce, is now considered unfit for human consumption. Gilles Arbour researched this subject extensively, and presents his findings in a convincing report titled Are Buckwheat Greens Toxic? His answer is, Yes!)
Because the little leafies are so densely packed, when watered from above their stems trap water which during very warm weather can cause the stems to rot. Watered by soaking from below, the stems will not trap water and will not rot. Such rot poses your one major risk of crop loss, so this is worth repeating: Watered by soaking from below, the stems will not trap water and will not rot.
Add liquid kelp or other liquid nutritional boosts to the bowl of water, if you wish. If you so choose, do so upon the first soaking. Once you’ve completed a daily cycle of soaking, some soil will remain behind in the bowl of water, especially for the first few days before rootlets have entwined themselves into the soil. Such accumulations of soil after many cycles of watering risk clogging the drain of your sink, so filter it before pouring it down the drain. Sprout jar lids with fine screens provide perfect filters. Or toss the remaining water outdoors. Or feed it to your houseplants, your inedible ones, as microgreens are your edible houseplants.
♦ WARMTH & Germination
WARMTH is a hot topic of debate. As the sun delivers its warmth and its light in the same package, it can be confusing which more affects plant growth. The shorter answer is: daylight. The longer answer is: before pondering growth, we logically first must examine germination, because germination and growth are two distinct stages that raise two separate issues.
Generally (which means, with many exceptions), germination does not require light, but does require warmth. The warmth required is loosely called room temperature, around 70 degrees F (21 degrees C ) during the day, though somewhat lower than that during the night. Thus even indoors, summer can be too hot and winter can be too cold.During winter, if you keep your home frigid, you can encourage seeds to germinate by moving them near a radiator or heater, or by placing a seedling heating mat under the containers of seedlings. Designed specifically for this purpose, their low wattage will not melt the plastic containers. But, and here comes a big BUT, beware the possible perils of PET recycle number 1, of which most fruit containers and seedling pots are made. Heat might cause its plasticizer to migrate into the soil. So disregard the instructions that accompany seedling heat mats, whose manufacturers and retailers are neglectful of this issue. Do not place plastic containers in direct contact with the mat.
Instead, if your kitchen cabinets are made of metal, you can affix seedling heating mats to a cabinet’s inner walls to create a “germinarium.” Lacking a metal cabinet, you can construct a germination terrarium inside a glass fish tank with an aluminum top, minus the water and minus the fish. If you shop for a glass fish tank at a pet store, there too you can purchase reptile heating mats, whose heat output are of the same low wattage as seedling mats. Reptile heating mats differ in that they come with the addition of adhesive to their backs, ideal for affixing the mats to the walls of your metal cabinets or glass germinariums.
Having affixed both a seedling heating mat and a reptile heating mat to the inner walls of a metal cabinet, I can attest that both work well and last long. In the winter, when my kitchen nighttime temperature descends to 60 degrees F (15 degrees C ) or less, the cabinet interior remains 70 degrees F (22 degrees C ) or more. This setup enables me both to grow sprouts and to germinate microgreens even in the dead of winter, thereby keeping my winters quite live.
Once germinated, most seedlings can tolerate fluctuations from 60 to 80 degrees F (15 to 27 C ). Most Brassicas actually flourish at 60 degrees F, so are ideal winter crops. Indeed, red pac choi’s leaves gain tinges of red and purple turnip’s stems stain purple only with exposure to relative cold. Non-Brassicas, however, that grow to harvest length in summer in seven days can take ten days during the colder days and shorter daylight hours of winter. And at 60 to 65 F (15 to 18 C ), still other microgreens such as basil dig in their heels and refuse to budge an inch. These you simply can postpone growing until spring.
Some seeds, for instance onion, beets and chard, germinate sooner and at higher ratios under the cloak of darkness. Other seeds, for instance mint and some lettuces and some basils (which actually are mints), require exposure to light to spark germination. If under contrary conditions, seeds still germinate, just delayed and at lower ratios. As most seeds that we grow as microgreens are not fussy and will germinate either in light or in darkness, we fortunately can tend to nearly all seeds equally. This one shared trait is universal: once germinated, all our seeds seek the light.
♦ LIGHT & Growth
Without light, microgreens remain merely micro and never turn green. But what light?
1) ARTIFICIAL LIGHT
Obsolescent incandescent (tungsten) bulbs generate as much heat as light, so can be too close for comfort. Fluorescent tubes emit more light than heat, so have long been used for indoor cultivation, but their wattage is limited. Thanks to a flourishing market for indoor cannabis, lighting technology has advanced with great innovations. These are led by digital ballasts that moderate higher wattages than do magnetic or electronic ballasts, yet they do so with less bulk, less weight, less heat, and less energy consumption. These newer ballasts in turn electrify a new breed of high-output lamps that include light-emitting diodes (LED), high-intensity discharge (HID) metal halides (ML), and HID high pressure sodiums (HPS). While all of these illuminate better than do incandescents, none can rival the sun (SUN!).
Artificial light promotes clearly measurable plant growth, but we do not know if wavelengths different from sunlight affect less tangible nutritional value. To further confound the issue, because they grow for only one or two weeks, microgreens grow equally well when nurtured with standard cool white fluorescent lamps as with full-spectrum grow lights. A fuller spectrum is necessary to spark flowering, or to conceive and nurture fruits and seeds, but microgreens never venture anywhere near adulthood, so never become encumbered with any adult responsibilities. They are the Peter Pans of the plant kingdom, singing elegies to never growing up. So if you already own standard fluorescents, for instance for your reading lamp to illuminate this very page, go ahead and use what you have for growing microgreens. Or if you already have full-spectrum bulbs and have had them so long that after much use they have lost their fullness, rather than try to change them just accept them as they are.
Collectively, all of the above can be called grow lights. While it is very easy to grow heavy with grow lights, your supplemental lighting need be neither elaborate nor expensive. If it hovers closely over your greens, a single fluorescent tube can suffice. Though too quickly for the human eye to notice, fluorescents constantly flicker. Thus the industry standard are fixtures that house double tubes, so that the light of one tube fills in the gap of the blink of the other tube. Two tubes are better than one, but better still is tubeless. Unlike the tubeless tires on automobile wheels whose treads are designed to wear away, the sun is tubeless and never tires.
Sunlight is natural and free, while your utility company charges for their charge. A lifestyle “off the grid” is commendable, but life on the electrical grid can be environmentally enviable, too, if you can limit your use of it. If just one of your windows provides direct sunlight for at least half the day, that is enough light. If that is not enough windowsill for your many trays of containers of microgreens, then construct shelves. Your one-time investment in pinewood and metal brackets will be reimbursed by the savings in your monthly electrical bills.
Sunlight both direct and unfiltered by glass is the ideal toward which to aspire. While some experienced gardeners advise against exposing seedlings to direct summer sunlight outdoors, such advisory concerns more the sun’s heat than its light, and the compounding parching effect of constant wind. If you provide ample water as well as shelter from wind, then most seedlings thrive under direct sunlight throughout the day. But you must make allowance for exceptions, because some shadowy seedlings flourish in partial shade. Signs of heat exhaustion in plants are wilt despite ample water, and signs of sunburn are dabs of discoloration on leaves similar to the sun spots on your grandpa’s face. Microgreens susceptible to heat exhaustion include dill, arugula (rocket), and many (not all) types of lettuce, and to sunburn include tat soi (a diminutive cousin of pac choi). Hot weather and hot sun will cause you greater discomfort than it will most other micros, so use your own body as a gauge.
Sunlight is the gold standard for light quality, but what about quantity? At the equator, daylight lasts 12 hours a day every day. At 40 degrees Latitude North (or South), an imaginary line in the sand in the north that traverses New York City, Salt Lake City, and Naples, Italy, daylight spans 10 hours on the winter solstice in December, and more than 16 hours on the summer solstice in June. Nowhere on the planet does the sun shine with the full intensity of summer high overhead at noontime for 18 hours a day. So you need not attempt to simulate that. Instead, think of your electrical lights as providing transitional twilight rather than noontime sun. Resort to artificial lighting as a supplement to, not substitute for, natural sunlight. Only during winter might you need to extend daylight hours with artificial indoor lighting.
For your sunrise and sunset times, consult your daily newspaper, an almanac, weather or astronomy websites, or just look out the window. Subtract one-half hour to account for dawn, add one half-hour for dusk, and then count your hours from dawn to dusk. For most garden vegetables,10 hours per day of mostly direct sunlight or 14 hours of mostly indirect sunlight can suffice. While these standards apply to most stages of vegetative growth, they are less crucial for microgreens. Under weak or scant sunlight, microgreens will need more days to grow, but they will still grow!
Seek the light! Under insufficient light, seedlings grow long and feeble stems in a futile attempt to reach for more light. Gardeners call this physically sad state legginess, which sounds like baby talk, while botanists call it etiolation. Beware long stems because stems generally are fibrous and bitter, while leaves tend to be tender and sweeter.
Some folks find that all their micros tend to grow long and feeble stems, so to remedy this they add one or two extra days of darkness, during which they place a plate or a tray atop the microgreens. Weighed down, the seedlings grow stems that are strong and squat. But plants seek the light of the sun, not the weight of a plate. Such folks mistakenly treat symptoms rather than solve problems, and the problem is lack of sufficient light. So instead of growing stems that are long and frail and fibrous and bitter, plants under pressure grow stems that are short and squat – and fibrous and bitter!
Conduct a taste test. Go to your fridge, and remove from the vegetable bin one large lettuce leaf. For this test, romaine lettuce serve best, butterhead and looseleaf lettuces will suffice, but iceberg lettuce not. If you prefer, wash the leaf. Now trim away the flexible outer leaf that generally is a deeper color green, and retain the stiff central spine whose color generally is washed out or white. Now eat only that outer leaf. Tender, succulent, maybe even sweet! Okay, after you’ve eaten all of the outer leaf, now eat the remaining central spine. Fibrous, bland, maybe even bitter!
If you already are growing microgreens, do the same with a handful of those. Snip off just the leaves with your fingers or your teeth, and eat only the leaves, but not the stems. Once you have a handful of stems, eat just those leftover stems. Once again, tough, bland, or even bitter! The leaves, not the stems, impart the delicate and agreeable flavor that makes microgreens so much prized. The smaller their leaves, the lesser your prize.
Chlorophyll in the leaves converts light energy into plant matter, specifically sugars and starches. Chlorophyll imparts the green in vegetable greens. Deep, dark, rich green in a leaf indicates more chlorophyll. More chlorophyll means more plant sugars can be produced. More sugars result in more flavorful veggies. While chlorophyll itself is not sweet, its presence makes plants sweet, and a meal of such plants makes our lives sweet.
Your goal is to grow lush leaves, not long stems. More simply stated: aim to grow leaves, not stems. Longer hours or stronger lumens of light produce larger leaves, shorter hours or weaker lumens produce longer stems. And your goal is not to seek just any light, but to make that sunlight. If to follow direct sunlight in your home you must move your crop from window to window, even from room to room, then if your are ambitious try to do so. And if the bright spot in your life happens to be a kitchen window near the kitchen sink, consider yourself truly fortunate for your Window of Opportunity.
Long hours of natural light do reach a natural limit, which is a good thing. Artificial light can artificially exceed that limit, which is a bad thing. Just as you need at least six hours of sleep, plants need a minimum of six hours of darkness. In an effort to maximize yields, some growers shine their artificial lighting 24 hours a day for the last three or four days before harvest. This is possible because plants do not rest at night as we do. Instead, after a long busy day at their home office creating carbohydrates, plants put in overtime and spend the night metabolizing and converting those carbs into plant tissue. They deepen their roots, thicken their stems, and broaden their leaves. In essence, plants work hard by day, and grow strong by night.
With uninterrupted light and no darkness, seedlings continually create their starches and sugars, but only barely metabolize them. Imagine stuffing yourself with foodstuff all day long and all night long, but never exercising, and never sleeping. Yet you still will grow. You will grow fat! Such obesity is a measure of quantity, not of quality. Plants grown under light round the clock become stressed, but if for less than a week then they gracefully endure their short-term stress. Microgreens grown under constant light do grow, and if they show no stress that is only because they are harvested before any signs might manifest.
We do not know if microgreens grown under light round the clock provide us with the same level of nutrients as those whose schedule more closely resembles that of nature. But we do know that nature knows best, and therefore can deduce that nature grows best. So provide your microgreens with the light of day, but also with the darkness of night.
To sum up about sun up: strive for at least six hours of darkness, and seek at least ten hours of sun.
3) REFLECTED LIGHT
Reflected Artificial Light. Reflectors can intensify artificial light. Create reflectors not with cumbersome mirrors but with lightweight white cardboard. The deluxe model is foam core board, which consists of two poster boards with, surprise, a foam core. Sold in office and art supply stores, they are as hi-tech as you need to get. Aluminum foil or metal-coated mylar sheeting affixed to cardboard are slightly more reflective, but much more unsightly. White is elegant. Trim the boards to preferred size, and prop them upright around the microgreens. This creates a lightweight light box that is collapsible when not in use and easy to store when out of sight.
Reflected Sunlight. Our most familiar form of reflected sunlight is the moon. Upon further reflection upon the subject of reflection, you might strive to provide light that is more intense than sunlight. But what light is more intense than the sun? Two suns! So with the sun shining through the window directly upon your microgreens, prop those white boards to the sides of and behind the microgreens. Merely one board in back works wonders. Boards are easy to prop upright if you create a fold two or three inches (50 or 75 mm) from one edge, and slide the fold under the tray of microgreens.
If you construct shelves across a window, you will be surprised and disappointed by how much light the shelves themselves block out. Wood grain is beautiful and natural, and the color of most wood can be described as blonde or beige, yet unpainted wood still absorbs a considerable amount of light. You can compensate immensely by painting the shelves gloss white, which reflects much light. Books upon bookshelves store knowledge, plants upon windowsills store light. Goethe’s deathbed last words were, “Light! More light!”
♦ The HARVEST
Congratulations! You and your tiny tender leaves have reached fruition.
1) SAMPLE and TASTE TEST the CROP almost EVERY DAY during its GROWTH
You likely will find peak succulence is reached before the second set of leaves emerges at the top. Cress grows as a cluster of leaves, but on most varieties the second set is a pair of leaves, just like the first pair. The first set is called the cotyledons, the second set the true leaves. The cotyledon seedling leaves are said to contain higher levels of phyto-nutrients, and generally taste sweeter, than the second set of true leaves. If you delay your harvest until after the second set has grown, your crop will be larger and taller, but might also begin to taste bitter and to turn fibrous. To create great works of art, the artist must know not only how to begin, but also when to stop. Likewise the great gardener.
2) HUSK the HULLS
Hulls may cling to the leaves of some species, for instance fenugreek, beet, radish, sunflower, and some varieties of lettuce. (Hulls cling so tenaciously to spinach as to eliminate spinach from the ranks of microgreens.) If you have not already done so, then certainly just before the harvest, lift up the container, hold it tightly, turn it sideways over a tray or trash can, and give your microgreens a massage. Brush the tops of their leaves gently with your fingers, the way you might pet a thick-haired Alaskan malamute dog or a long-haired Peruvian guinea pig. Despite your intention to aim for that tray or trash can, the hulls still will go flying elsewhere, so prepare accordingly.
3) GIVE YOUR CROP a HAIRCUT
A week earlier, when you filled the container with soil right up to its brim, you were preparing for this final step of snipping the stems just above their base in the soil.
Delegate a pair of sharp scissors to use solely for harvesting. Scissors warrant a detailed discussion to ensure a clean cut of the stem if you refrigerate them rather than eat them upon harvest. A clean cut increases the longevity of your greens by guarding against rot or bacterial growth that more readily occurs upon the larger surface of a jagged laceration.
Gardening shears, sold in gardening stores, and herb snippers, sold in kitchen supply stores, both have blades that are purported to be razor-sharp, but not really. If they were as sharp as razors, they would easily cut your fingers, and you would bleed all over your greens. Not very vegetarian. While sharp, the blades on such scissors often are too short. On the plus side, some gardening shears have blades that disassemble for easy and effective cleaning.
Barber scissors (barber shears) are sold in pharmacies and hair salon supply stores. Their blades generally are long and thin, so you can slip their slender blades between seedlings, and selectively harvest without disturbing the rest of the crop. For ease of cleaning, seek barber scissors constructed all of steel. If the handles have plastic-coated grips, be sure the thick plastic layer does not reach up to the joint, else the joint will be difficult to clean and wash and dry.
Barber scissors are relatively expensive, and pharmacies generally stock one size only. For the sake both of variety and frugality, seek scissors in an office supply store. There you are sure to find more affordable scissors with long blades, some of them even with claims of anti-microbial properties.
When harvesting piecemeal, cut patches or rows into which the remaining greens can lean into as they grow. Gather a bunch with the tips of your fingers and snip at the base of the stems. If you intend to share your little leafies with your family or friends, you owe them the courtesy of first washing your hands.
When harvesting the entire crop all at once, lift the container over a dish, tilt the container on its side, cut the greens with broad strokes, and the cuttings will fall into the dish, untouched by human hands.
Harvesting piecemeal allows you to sample from day to day, which you will especially want to do as a beginner. Some greens taste better before the true leaves appear, others will taste the same, others might taste worse. If you allow the remaining greens to grow for more than another week after first harvesting a patch or a row, be wary that mold might develop on the stubble. At the first sign of mold, you might choose to remove the stubble entirely, for which procedure patches are easier than rows. Strip the stubble, lay the soil bare, and you will prevent any further growth of mold.
Banish soil from your harvest. Be careful not to lift any soil along with greens. Once snipped and while still in your grasp, inspect the undersides of the stems for any clinging soil. The tip of the scissors in your one hand just happens to serve as an effective tool for flicking off any soil in your other hand. When finished with the scissors, wipe clean the blades, and wash and dry them as needed. Care for your scissors as you would your forks and spoons.
Do not rinse your harvest, unless you must wash off errant soil. You especially do not want to rinse if you will serve the greens during the coming days, and so intend to refrigerate them. Moisture, even under cool temperatures, increases the risk of rot. If you nevertheless must rinse your microgreens before storage, then consider drying them upon a smooth towel or in a salad spinner. Spinning adds not only one extra step to your workflow, but also one extra contraption in your kitchen.
4) CLEAN UP
After a full harvest, tip the remaining cluster of roots and soil upside down, and except for root vegetables such as beets and radish the cluster will slide right out from the plastic container. Compost or simply dump the clump outdoors, where animal visitors will pick it clean for any remaining edibles. Between crops, commercial microgreen farmers routinely rinse their trays with dilute bleach as a disinfectant, but as a measure against bacteria and mold that probably is overkill. As a home gardener, you need only to dismantle the doubled-up containers, then to allow them to dry out in open air, and to store them dry before refilling them with soil. Only drying them out between cycles, I have reused the same containers dozens of times, yet never have seen any hint of contamination.
5) PROTECT YOUR ASSETS
During storage or transport, protect the fragile microgreens in a hard container, not a bag, though a bag will suffice if handled gently. Refrigerate what you do not plan to eat immediately. (But do not refrigerate basil or amaranth, which under cool temperatures turn to mush.) The closer to freezing point you keep the thermostat on your fridge, the longer you can keep fresh your harvest.
Alternatively, you need not snip your crop, but can refrigerate the entire container, soil and all. Your pint container can fit right in with other pint containers that still contain their berry forebears. Just place it into a plastic bag, the bottom of the container in the bottom of the bag. To safeguard against crushing the outstretched leaves, pull up the sides of the bag, trim them if much taller than the greens, and tie together the edges at the top of the bag. A day before harvest, remove the container from the fridge, strip away the bag from the container, and freshen up the greens by returning them back into room temperature and into the light.
6) CELEBRATE YOUR HARVEST
Eat your microgreens immediately upon harvest, and appreciate their flavors just as they are, unadorned by sauces and unadulterated by seasonings. Any condiment you might add to them makes a mockery of microgreens. Nor should you use your microgreens as the condiment. Some upscale restaurants adorn microgreens atop a hunk of steak or pork, in essence serving an ounce of prevention atop a pound of carcinogen. Chefs garnish with microgreens more to embellish the printed menu than to stimulate the palate, as the microgreens’ culinary flavors are overwhelmed and curative powers are negated by the chunk of carcass. Mixed into a salad amid their elders, microgreens’ flavors are not added but are lost. And let’s be honest. Not all microgreens taste luscious, so that could be the very reason for dispersing them amid lettuce and tomatoes.
No recipes are needed, at least not initially. Simply remember what Mama told you. “Eat your greens.” Mama Nature tells you the same. Cooking microgreens is almost sacrilegious, as it renders them into mush. And if you do tire of eating microgreens, you sooner will tire of growing them.
Despite potential obstacles, your labors surely will reap the reward of sustenance in abundance. You do not need a green thumb to achieve fruition. Even a pink pinky will suffice. But you do need patience and persistence. Tending to your microgreens will be a joy, not a chore. Grow them knowing that you are being good to them, and thank them knowing that they will be good for you.
The above text appears in a much shorter format as a new chapter in the 2011 seventh printing of my book SPROUT GARDEN.
The above full text and much more will be paper-published as a book.
The forthcoming book is titled MICROGREEN GARDEN.
If you have any suggestions or corrections, please share them with me, as here I have shared my suggestions with you.
please email me at: herman[dot]melville[at]yahoo[dot]com
– Mark Mathew Braunstein
April 11, 2012