ABSTRACT

Often people are somewhat confused as to what are the differences among sprouts, microgreens, and baby greens or mesclun mixes� These classes of products are really differentiated by their size at harvest� In terms of age and size, their categories are as follows: sprouts-youngest, grown in dark, smallest, with the presence of many seed coats; microgreens-somewhat larger in size and older (usually 2″ tall) and grown in full light; baby greens or mesclun mixes-are the oldest and largest (usually 3-4″ tall)� Baby greens or mesclun mixes are also cut several times before replanting, whereas, sprouts and microgreens are a one-time harvest� Sprouts are germinated seeds and eaten in entirety (root, seed, and shoot)� The edible portions of microgreens are the stems and leaves�

Chapter 26 presented information on sources of seeds and the types of microgreens� Use different seed catalogs and look for a section on microgreens or search websites that have information such as those listed in the Appendix�

Microgreens are easily grown for home use� I have found that the simplest system to grow them is in plastic trays� The following text lists the supplies needed to get started�

These are standard flat trays of 10½″ × 21″ used for propagation� The difference, however, is to obtain these trays without holes� They are available from garden centers and online from greenhouse suppliers such as CropKing (see Appendix)� The tray acts as a reservoir to retain moisture for the growing substrate� They may be re-used between crops by sterilizing with a 10% bleach solution�

In my experience with growing microgreens, the best medium is the “Sure To Grow” (STG) mats� These are special capillary mats made for microgreen production� Refer to the Appendix for their website� The only problem with them is that you have to purchase a case of 300 pads for about $200� An alternative is to use several layers of thick paper towels� They are not quite as good as the capillary mats but they will serve the purpose�

As discussed in Chapter 26, these are available from some seed houses such as Johnny’s Select Seeds (see Appendix)� However, you may use almost any crop that you feel would suit your needs� But one note of caution: purchase only untreated or organic seeds that have no fungicide coating� The use of fungicide on many seeds is to prevent damping off disease of seedlings�

You will note their presence by the seed coat color of yellow, orange, red, green, or other unnatural color of the seed� Some seeds may only be hot-water treated, so they would be okay�

Household bleach or Clorox is adequate� As explained in Chapter 26, dilute it to 10% with water� More details of this are presented later�

Purchase a basic vegetable formulation from a hydroponic supplier online or at a shop (see Appendix)� Dilute the nutrient solution recommended rate to half strength�

Make a stand of polyvinyl chloride (PVC) pipe to support two 30-watt compact fluorescent bulbs about 1 ft above the microgreen tray� You could use an aluminum pie plate or other reflective surface just above each light to reflect the light toward the growing tray�

Use an inexpensive time-clock such as ones used in homes� It should be a 24-hour clock with 1-hour intervals�

Measuring cup or graduated cylinder� A small colander (strainer) to catch seeds as you rinse them during the steril-

ization procedure� Disposable gloves to handle the seeds after sterilization� A teaspoon (tsp) to measure, stir, and spread the seeds on the substrate in the tray�

The most popular seeds used were discussed in Chapter 26� Remember to select seed combinations within any tray that have similar growth rates� That is, avoid mixing slow-growing seeds with fast-growing ones so that your crop develops evenly and at the same pace�

Successful growing depends upon the prevention of diseases from entering the growing tray� For that reason, I do not recommend growing microgreens outside as they will quickly become contaminated with fungi and bacteria that blow in the air with windblown dirt� The best location is on a kitchen counter or in a spare room or basement of your home�

Since you are using raw, untreated seed, the seed surface may contain bacterial or fungal spores that would quickly germinate when the seeds are placed in a moist environment in the growing tray� Surface sterilize with a 10% bleach solution (dilution of one part of bleach to nine parts of water)� Make this up in a measuring cup or graduated cylinder (Figure 27�1)� Pour the solution into a glass with the seeds and stir with a spoon for 4-5 min� You will have to determine the amount of seeds needed per tray to get the correct density� Be careful not to sow the seed too thick as that will cause crowding of the germinating shoots resulting in weak, elongated stems that are very susceptible to fungal infection� From my experience use 3 level tsps per tray of Amaranth, or lettuce, 2 tsps of Mizuna or Komatsuna, and 7-8 tsps of radish per tray� You will have to experiment with this density to find the best for any specific crop�

After the sanitation process, rinse the seeds with clean, raw water� Place the seeds in a strainer and rinse� Moisten the paper towels or capillary mat with raw water before scooping the seeds from the strainer with a spoon and spreading them evenly on the

substrate in the tray� Add only sufficient water to fill the grooves in the bottom of the tray until it touches the bottom of the medium� If you fill it too much, the excess water will cause the seeds to float into clumps� You may continue to spread the seeds evenly with your finger as long as you do not touch other things� Add raw water daily for about 3 days until the seeds form small roots (radicals) and shoots (Figure 27�2)� Carefully add water at one end of the tray and let it flow by capillary action through the substrate to the other end to avoid floating the seeds� Once the seeds have germinated, their initial roots (radicals) will penetrate the paper towels or mat and secure themselves� Subsequent watering and addition of nutrient solution on a daily basis may be done from above using a watering can with a sprinkler breaker spout, but still take caution in not adding too much water that may cover the seeds� The water level should always be maintained in the tray grooves to the base of the medium�

Within about 3 days when the shoots have grown about ¼–½″ in height, start using a half-strength nutrient solution� Purchase a vegetable formulation concentrate from a hydroponic shop or online and make it up to half the recommended rate per gallon� Store some solution in a dark container of several gallons� The seedlings at this time will have attached to the medium, so they will not drift as you water them� Adding too much solution at a time will inundate them causing lack of oxygen� If you add too much you can tilt the tray to let some drain off� In fact, draining the tray between watering will help to add oxygen to the root mass underneath the medium� Do not use any substrate such as a peatlite or other mix as that will cause excessive moisture levels in the tray and can also introduce substrate getting onto the microgreens during harvesting�

Microgreens are ready for harvest when they are about 1½–2″ tall at their cotyledon stage (radish) (Figure 27�3) or the initial stage of the first true-leaf formation� Do not allow the first true leaves to expand beyond ¼″ with most varieties� Lettuce true leaves may expand a little more approaching ½″ in length� This stage may vary from 5 days with radish up to 12-14 days with slower-growing varieties such as amaranth� If you want to harvest over a few days begin a little earlier in the cropping cycle� With a scissors cut a section of the substrate with the seedlings and remove them from the tray for immediate use� Cut the seedlings just above the surface of the substrate cutting only the shoots and not the seed coats (Figure 27�4)� Collect them in a bowl for use in your favorite salads or other dishes to get a nice added touch to taste and appearance!