Microgreens are the quickest and most intensive crop that we grow. Parsnips take 120 days from seeding to harvest, heads of lettuce can be grown in about 60 days, while radishes and arugula, our quickest crops in the field, can be harvested as soon as 3 weeks after planting during the height of the summer. Microgreens can be sown and then harvested within a week to a week and a half, making them a fantastic crop to get us through the short days of winter when everything grows super-slowly. And while you might think that they are only useful as a fancy little garnish, they pack a real wallop in terms of both flavor and the phytonutrients that are the reason your mom told you to eat your greens! One study found that microgreen seedlings of red cabbage, cilantro, and radish had up to 40 times concentration of the vitamin E, C, K, lutein, and beta-carotene of their mature counterparts!
So how do we grow these tasty little treats in the winter? I often like to think of our protected structures in terms of a pyramid from the least protected structures, which are cheaper and so we can cover more ground with them (right now the caterpillars where we are harvesting kale are the bottom floor of the pyramid) up to the most protected zones. Microgreens come from the very top of the pyramid, the heated bench in our main greenhouse. We have a wood pellet boiler that produces hot water used to power a radiator that keeps that main greenhouse just above freezing all winter long. The main body of the greenhouse is a great place for the salad mix, lettuce mix, chard, arugula, and pea shoots that grow during the balmy but short days and then hang out for the long but not-quite freezing winter nights. That hot water is also circulated through tubes in two 5′ X 30′ benches that we use to start seedlings for transplanting out into other greenhouses, and eventually into the field. We also use that heat to start microgreens. The seeds for the microgreens are thickly sown in flats, and then lightly covered with vermiculite. With some nice heat from underneath, they pop up and are ready for harvest lickety-split! You can just barely see the germinating seedlings in the picture below, a day and a half after planting:
Thank you! I requested a story about how you grow microgreens just a week ago, and here it is already!! One question not answered — how do you wash them to get the vermiculite out? (And can you reuse the vermiculite over and over?)
We LOVE your spicy microgreens! I forget if you ever said exactly what they are …?
What is Vermiculite and do you really need it to grow the microgreens? I was watching a video of a farm that grows them in the house in a room on mats made of pressed coconut shells. There was no soil at all to decrease the chance of contamination. The first thing they did was spray them with hydrogen peroxide of a certain percent to keep the germs down, ( they only did this when they spread them out on the medium) and they used water that was filtered to spray them down frequently. It was very interesting to SEE how they did it. Everything was grown in containers that were food-safe plastic of the safer kind of plastic. While the seeds first germinated they did not need any light at all, and they were covered with a piece of styrofoam that fit right into the tray but was held up from being directly on top of them by toothpicks in the styrofoam. They had some patented lights about three inches above each tray after a few days, and the trays were stacked eight high on chrome plated metal shelves. One room grew a lot of microgreens. Part of their business was teaching and setting other people up in business growing microgreens. They will set you up to do it as a business for a thousand dollars and two full days of classes there are included. They said they make a hundred thousand dollars a year on that room. They sell the sprouts as plants right now because there are fewer regulations on selling plants. People buy the whole tray or a plastic box with a smaller square of them and cut the microgreens off themselves. That way you do not have to worry about shelf life or food poisoning which can be a problem with cut sprouts in a package. Restaurants buy them from them, and individuals buy them from them. They sprouted a lot of microgreens, I think that there were fourteen kinds. Everything looked so healthy.