Microgreens are small immature vegetable greens, they are different from sprouts in that they are harvested after the sprout stage but long before the plant reaches maturity. They are also differentiated by some culinary aficionados from 'baby greens' as baby greens can be considered veggies that have just started to reach maturity but are still basically adolescents.
They are in demand and becoming increasingly popular. Their popularity extends far beyond their "Fad-Appeal", they are tasty and succulent as well as healthy, extremely healthy, microgreens contain four to six times the vitamins and phyto-nutrients found in mature leaves of the same plants.
Multiple herbs and leafy vegetables can be used as micro-greens. They are used in salads, as garnishes, and melded into soups and sandwiches. Microgreens are nutritiously endowed as well as tasty, a winning combination. They are considered a 'specialty produce' and can be hard to find and costly at times, which makes them a lucrative crop to produce via hydroponics.
Some of the more common varieties of microgreens are Argula, Basil, Beet Greens, Brocolli, Buck wheat, celery, chia, cilantro / coriander, clover, cress, dill, kale, mustard greens, pea shoots, kohlrabi, radish greens, spinach, soret, sunflower, tatsoi, turnip greens.
Dozens of plant species can be used as micro-greens and all have their own distinct qualities and characteristics. Radish microgreens for instance produce intensely colored tiny leaves that contain elevated levels of antioxidants proven to have anti-carcinogenic properties, wheat grass is another micro-green, while the taste is not as appealing as many other plants it has tremendous benefits as a health food.
In addition to their taste appeal and health advantages they can be rapidly grown using conventional gardening methods and even more so in a hydroponic scenario. Humidity, nutrition, temperature, light, and of course variety are all factors that effect the growth rate. In an artificial hydroponic environment these can all be manipulated to expedite a quick harvest.
Micro Green Startups
At current market prices, if you plan on growing them commercially they can be a very lucrative cash crop.
Growing microgreens is not nearly as expensive as conventional farming, you shant need costly equipment in the initial phases, startup costs can be quite affordable,. Investment in hydroponic equipment, which can be added onto as you go should be the biggest investment.
In my experience the simpler the system, the better so far as microgreens are conerned. A simple inexpensive flat tray that is manually watered will suffice for beginners. Placed on a declining angle to allow the nutrient solution to flow through unimpeded and drain on the lower end.
No granular growing medium is needed. The most efficient and least labor intensive way to produce micro-greens rapidly is with a seed capillary mat that holds the seeds in place while retaining ample moisture. Most capillary mats have a wicking action - they draw water up and retain it. Capillary mats can be used in conjunction with Rockwool or similar media, burlap or similar cloth. You can devise your own or find suitable manufactured products which are sold as hydroponic microgreen pads.
Seeds and Seeding
Seeds used to grow microgreens should be untreated seeds, organic is best if at all possible. The same seeds used to produce stanfard full size plants are the same used for micro greens. The primary difference is that seeds planted for micro greens are sown much closer together, so it will takes more seed to grow microgreens than standard crops. Purchasing seeds wholesale once you get past your initial experimental stages is advisable.
Optimal seeding density varies slightly among variant species, but no formula is written in stone. Basically figure out the spacing of what the mature plant would need and reduce that expotentially. If you sew them too dense - no biggie you can thin them as need be, if you sew them too sparse - you'll have a slightly smaller harvest and know better next time [next week ?]
Any seeds can be used, however there are advantages to using seeds that have been pre-packaged specificially for the purpose of producing micro greens or sprouts. They are supposed to be processed in such as fashion as to exclude foreign matter and have not been chemically treated with fertilizers and fungicides.
Some seeds pre packed as microgreen suitable seeds excrete a mucus or mucilage once they have been dampened. This mucilage is spongelike and retains moistue , it also acts as a protective barrier once wet.
Hydroponic MicroGreen Requirements
Microgreens require minimal space and can be harvested in less than a week from seeding for many varieties. They are harvested once the plants have developed their first set ot true leaves as opposed to embryonic leaves.
Microgreens can be sown at a much higher density than seeds sown with the intent of producing full grown mature plants. They can be compacted into a relatively small area. This is an advantage, but if you use the wrong media it could work against you, so you'll need to avoid using small substrate, vermiculite and so forth.
As soon as they break out of their seed shell, germination, your infant plants begin crying for light and nutrients.
In a hydroponic scenario you will more than likely be using grow lights. Artificial light shouldn't be too intense, propagation lamps are ideal. If you don't have, or are unwilling to spend the money for propagation lights a simple, preferably low heat, fluorescent will also work, although not as effectively.
When applying a nutrient solution to micro greens you most certainly want to do so modestly, not only the dilution ratio, but you must avoid flooding out the sprouts of micro greens or over saturating them. Not only can they be easily washed out but they are also highly prone to fungal issues.
Nutrients aren't needed until the cotyledons emerge at which point chlorophyll has formed and photosynthesis is commencing, the seedling has also pretty much exhausted its embryonic nutrient reserve at this point.
A simple nutrient formula is sufficient. There are formulas concocted specifically for sprout and microgreen production, but there are so very many variables relevant to the myriad of crops used as micro greens that they need to explored seperately. Grasses for instance such as wheat grass, alfalfa grass and even corn have a very different EC requirement than most herbs or vegetables.
To simplify the equation, a slightly diluted version of what would be used for the adult plant can be used on the micro green or sprout. Also keep in mind that pre formulated solutions generally have recommendations for dosages on the high end of what the plants actually need - the companies that make these formulas ARE in business to sell their product ....
Problems - Troubleshooting Hydroponic Microgreens
Rot and Fungus are the evil twins that most commonly infest mciro green and sprout production. Both problems are derived from excess moisture and humidity ,improper drainage and poor ventilation. Proper ventilation removes lingering humidity - air borne moisture. Something as simple as a small portable fan can contribute tremendously to fighting back rot and fungus as well as bacterial issues.
A proper flow of nutrients through what ever system you choose is also vital, avoid flooding and over saturation. There is a thin line between hydration and saturation - with micro greens when in doubt a tad less water is always the best option , just enough not much more.Micro greens that have passed their peak of maturity will frequently flop over. This not only makes the harvest more difficult it also contibites to a soggy salad when the top of the plant droops into the solution - not to metion a written invitation to the rot and fungal twins, as well as their nefarious cousin bacteria to make an appearance.
Micro greens have a very narrow window of opportunity so far as harvest is concerned. At the peak of perfection they should be straight and robust but short and stout. If they are over mature all is not lost, you can still go for baby greens or even allow them to strive towards their full potential as adult plants.
When harvesting they are best cut with sharp scissors or shears. They should be cut above the substrate / media high enough so as to avoid contamination and or contact with the media that they are grown in. A small stub of the plant should be all thst is left behind.
This becomes even more urgent if you used a granular media as it can be easily picked up and intermingled with the greens in the harvest process.Micro greens are best harvested when the foliage is coolest earlier in the day. This will not only help create a tastier healthier product but prolongs its shelf life as well.
Summary Hydroponic Micro Greens
1. Place the Capillary mat in your tray and permeate with pH balanced water The ph should be 5.5-6.5 for germination. If you are using soil instead of hydroponics 6.5 to 6.8 is best. See - pH in Hydroponics
2. Broadcast the seeds uniformly over the mat and spray again with a mister.
3. Until they germinate light is the enemy, cover the tray with a dark lid to prevent too much light from reaching the seeds.
4. Until germination occurs you'll want them in the dark, but the lid needs to be removed for short duration's to allow for air circulation and to mist them periodically. Air circulation once every 12 hours - misting every 18 - 24.
5. Once the seeds begin to germinate, the seed shells have been breached, remove the lid and place your lighting above the tray.
6. Stop misting at this point watering is best done by dribbling small amounts of nutrient enriched water into the tray itself. A weak nutrient solution at about 1/4 strength or less produces the best results. Some growers do not even use nutrient solution, simply pH balanced water and do just fine so long as they are growing rapidly maturing cultivars.