One of my many hats besides coordinating breeding efforts is helping to run the Eastern Campus Botanical Center in Riverhead, NY. Part of Suffolk County Community College, the Center is a resource for horticultural and natural science information and training on the East End of Long Island and we teach ecological land care, identification of native plants and in association with the Culinary Center which is also part of the Eastern Campus, some courses related to that discipline. Because of the off-season demand for micro-greens among the upscale restaurants we did an extensive trial and evaluation run to see what the potential might be.
By definition micro-greens are seedlings harvested when the first true leaves appear (just after the cotyledon or seed leaf stage). They are appearing in upscale markets and restaurants and locally command a luxury item price of up to $3 to $5/ounce (that is "per ounce"). Those who sing the praises of micro-greens point to their nutritional benefits. Like sprouts, some types of young seedlings have remarkably high levels of vitamins, minerals and other health-giving phytochemicals. Chefs look at their sometimes intense flavor or the color and texture that they offer asdish confetti, brightening up main dishes or salads. I don't know, I think of them mostly as a kind of fad but we'll see. They probably said that about parsley.
Some "greens" are well suited for sale and consumption at the cotyledon or micro-green stage, others kinds of greens are best harvested at the "petite stage" or the larger "baby stage" where the plant has developed clustered leaves. Harvesting at these extremely young stages consumes the entire plant just as the growth is about to become exponential. For many farmers and growers of "greens" it seems counter-intuitive that one would harvest plants just as they were reaching their potential. Most growers of microgreens are indeed not farmers but "sprouters" who don't work in the field; but instead, grow in hoop houses or warehouses using hydroponic techniques. Farmers generally wait to the "young stage" to harvest immature leaves are blended together to make up a mesclun. In shearing the young leaves, they leave the plant's crown that can provide additional "flushes" of leaves to harvest.
As an experiment; students, faculty and visitors evaluated over 50 kinds of microgreens which were grown at he Botanical Center to learn about their potential, care and requirements. These were sown on Jan 18 and Jan 29. Earlier sowings were grown at lower night temperatures (45-50°F), later sowings at slightly higher night temperatures (60-65°F). They were grown in a polyhouse environment until the last two weeks, then moved into a glass house (70°F) for evaluation and display purposes. All seeds were thickly sown in half flats with either a peat/perlite mix or compost mix fortified with a dry organic fertilizer. Once transferred to the glasshouse they received a weak water soluble fertilizer solution. While available literature describes micro-greens as a 14 day crop, winter sun angle at 40°N latitude and further decrease in light due to growth under plastic as well as lower growing temperatures extended this time dramatically. Photos were taken on March 12.
Although the common Genovese basil took a long time to grow to microgreen size and required warmer temperatures to germinate well, it was appealing from both the flavor and attractiveness as a garnish. Genovese basil can be sown quite thick, is available and economical in large seed quantities. 40 days from January sowing. Rated very highly as a micro-green.
Curled Cress is available in large seed quantities for low cost and develops into an attractive microgreen. It can be grown slower at lower temperatures. Ours fared well at moderate temperatures. Crinkled Cress from Frank Morton's breeding program and available from FEDCO seeds had a better texture. The greens are pungent, hot with a strong mustard like flavor, (maybe a bit like horseradish) that is pleasing and could complement a number of foods. Favored as a "petite" green, harvested with several small leaves when it is most attractive. 40 day harvest.
At the young 50 day stage, chard and red beet (right) develop into nearly identical microgreens. We didn't notice much coloration with the rainbow chards except for the red stems of some. Some kinds of beet such as Bull's Blood produced darker, attractive micro-greens (no photo). Both beet and chard produces crisp and juicy microgreens with a pleasant light spinach flavor. Micro-greens can grow quite thick since each fruit (corky seed ball) can produce two or more plants. We favored the "petite" stage seen here.
Celery seed is small and a slow finicky germinator which requires some care at it's early stages. Seed is available at low cost. Even at 50 days, it would probably be better to figure 10 additional days for harvest in line with the other micro-greens here. Celery tolerates lower night temperatures well but was probably delayed by those temperatures. On the other hand, it has a refreshing strong celery flavor and is complementary to many kinds of dishes. I was rated highly as a micro-green.
Chervil produces an attractive "petite" green, developing a pleasant mild anise flavor with some complexity at latter stages. The carrot-like leaves are more delicate in flavor and of a finer quality than parsley. Possible garnish for fish, young steamed vegetables. Well liked by most evaluators. 40 day maturity.
Purple and green orach produce large leaves on tall seedlings; tender baby greens of substance. Mild spinach flavor. Frank Morton of Wild Garden Seed has collected, maintained and developed new strains of Orach in an exciting color range. Orach is probably best in this stage.
Clayona also known as miner's lettuce was pleasant and mild, some say buttery texture, the many basal leaves of the "baby" stage plants are very novel and attractive in their tiny bunches. Most people preferred over "baby" lettuce. Definitely worth growing as a salad, highly rated. 50 days.
Cilantro is mild and has a pleasant coriander flavor (the seed is coriander spice), described as parsley-like with citrus overtones. It's a very attractive and very usable "petite" green. Delfino Coriander was more pleasing in flavor; Santo Coriander was somewhat astringent even though grown under similar conditions. Delfino would be preferred over parsley as a garnish by many tasters.
Garland Chrysanthemum cv: Tiger Ear, from Evergreen Seeds produces quite a bit of biomass from a few seeds and in a short time. We found the microgreens crisp and juicy, mild and pleasant; toward later "baby" stages there is an interesting hint of mum leaf or aromatic field daisy which adds considerably to interest. There are many kinds of edible chrysanthemum that are popular in Eastern Asia, this is a fine one. We prefer this stage for the succulent tasty leaves over harvesting from more mature plants.
Fennel had a cooling delicate anise like flavor, attractive cut leaves. A good complement to fruit salads, yogurt sauces, poached fish, cheeses; very nice garnish and flavor as a "baby" green. We used the Italian or Florence Fennel for producing "greens" but there are other kinds available including a bronze foliage type. You either love it or hate it as demonstrated by taste tests. I find that a little really brightens a salad.
Parsley is always considered a fine garnish and flavoring ingredient. As a microgreen, the parsley flavor is more mild. Gigante and plain leaved varieties were trialed- Gigante had excellent, quick germination which does not always happen with parsley; curled kinds would probably produce attractive microgreens. Favored in trial perhaps due to familiarity.
Dark Opal Basil
The color is the main attribute to Dark Opal Basil, slow growing, requires warmth. A fine micro-green addition but not all that tasty. Most evaluators would opt out.
Onion, chives, garlic chives and leek are all similar in requirements and provide nice microgreens which are rich in flavor and quite different from one another. We evaluated a number of edible, common alliums, all have potential use at young stages. They need time to develop and can be sown quite heavily. 50 days.
As a "baby" green, Chicory is tender with a pleasant flavor some describe as flowery but with a slightly bitter aftertaste that is always appreciated in salads with a vinaigrette dressing. Leaf chicory or endives are similar in flavor and growth as microgreens.
Lemon Basil like all basils require warmth for good germination. Very fine lemon flavor, ideal garnish for many items as well as salad. Evaluators find it outstanding at the "petite: stage and enjoyed the refreshing flavor.
Tatsoi had attractive, glossy round leaves of substance. The flavor was mustard like but very mild. A nice quick growing crop.
Vitamin Greens / Mustards
Vitamin greens were mild and pleasant. This is a mizuna-type mustard. Johnny's Seeds is a good source for seeds for Vitamin Greens as well as other micro-greens and "baby" greens since they have done extensive work to commercialize this salad niche.
Ruby Streak is another mustard introduction from Evergreen Seeds. Attractive, quick growing "greens", can tolerate lower temperatures. Hot with a slight bitterness. Visually, a nice garnish.
Orient Golden Frill is an introduction from Evergreen Seeds into the "petite" green arena. Very pretty, hot mustard flavor. Just like the condiment at a Nathan's stand. Evoked some discussion of potential uses on the plate.
Rapid growth, this open pollinated tall white stem pak choi (a low cost seed) was an easy bolter under short days and the cold, crowded growth conditions which may actually add to it's desirability. It had a very mild flavor, no mustard heat and had a pleasant crispness especially as the bolting stem develops as a "baby" green.
Large leaves, light purple stems and leaf petioles, common purple kohlrabi had a mild raw broccoli flavor, so does broccoli (just use the lower cost non hybrids).
Red Russian Kale was a particularly nice "green" with frilled leaves and purple overtones. White Russian is a green counterpart.
Other "greens" that were grown as part of this investigation but not photographed were: carrot greens (received high marks for flavor at "petite" stage), amaranth, corn salad, various lettuces, turnip greens, broccoli raab, broccoli, red cabbage, purple mustard, flaxseed, arugula, and radish.
This was a preliminary grow out of many kinds of seeds. More work is required to develop techniques of economical production and marketing of these greens under traditional and organic systems. It does seem to be possible for home gardeners to grow these in simple soil flats or even ground culture under protective cloche or cold frame to experience these gourmet greens early in the season. I would like to thank Paul Anderson, Eva Skolak and students in my Botany Class and continuing education "Sprouts and Microgreens Course" for assistance with the evaluation.