How to grow (and harvest) your own microgreens at home, all year long

JUST BECAUSE IT’S the depths of winter and your house gets only about 20 minutes of light each day, doesn’t mean you need to stop growing vegetables. If you’re looking for a way to keep growing your own fresh food, look no further than the wonderful world of microgreens.

Microgreens are just what they sound like: ridiculously small salad greens. If you set up a microgreen station at home, you can produce food year-round with a minimum of space and time. If you’ve ever started seeds in your windowsill for transplants, you’ve already mastered the key skills of microgreen production. Microgreens are vegetable transplants that are grown very closely together and harvested just a few weeks after they sprout. It’s about as close as you’ll ever get to instant gratification in vegetable gardening.

You can grow flats of arugula, broccoli, mesclun mix, mustards and just about any other crop with edible greens.

Microgreens can be grown in any tray or shallow container with drainage holes. I find that you get a good-size harvest growing them in a standard nursery flat. These hold a little bit of water, which helps keep the soil moist. However, when growing microgreens, there is a real risk of oversaturating and drowning the greens, so you don’t want your container to hold too much moisture.

Unlike nursery transplants, microgreens are pretty forgiving about the growing medium you use. Because they’re harvested so young, they don’t really need to draw too many nutrients from the soil; it’s mostly there just so the roots have something to grab on to. You can use potting soil, germination mix or even straight garden soil as a medium. If you’re using a shallow container like a nursery flat, fill it with 1 to 2 inches of soil, about halfway to the top.

Microgreens can be grown with natural light or under a grow light. Supplemental light helps the plants grow more quickly and evenly, but microgreens easily can be grown on a windowsill. If you have a grow light, put on a timer to run the light four to eight hours a day. This will help the greens grow faster and straighter. 

The quantity of seed needed for each flat of microgreens depends on the size of the seed itself. Generally, larger volumes of seed are needed for larger seeds, although the total number of seeds might be less. For example, a flat of cilantro, which has a pretty large seed, might use between 1 and 2 tablespoons. A smaller seeded crop like broccoli might use only 1 teaspoon per flat. You can order seeds for microgreens online, or you might be able to find them in the bulk section of your grocery store, where they’ll likely be labeled as seeds for sprouting (also a good winter growing project).

Microgreens don’t really need a lot of attention. They won’t need any fertilizer, although a soil mix with compost can help ensure the plants have access to nutrients if they need them. Microgreens do best if you use overhead watering until they germinate and then switch to bottom watering. Bottom watering prevents the thin, tender sprouts from being knocked over by a gush of water and getting dirty. The plants are often so leggy, they can’t easily right themselves if knocked down.

Depending on crop, temperature and light levels, your greens should be ready to harvest in about one to three weeks. Generally, they’re cut when they just begin to show their first true leaves, but you can cut them at any size you like. 

Like any gardening endeavor, it’s best to ease your way in. Try starting one or two flats of microgreens a week. Because they go fast and don’t store long, you’ll need to start new flats each week to keep a steady supply. Because of the quick turnaround time, it’s easy to ramp up or down based on your actual use. If you get going now, you can have some greens ready for day one of your salad-every-day New Year’s resolution.