Winter is slowly coming to an end around here and it is nearly time to start lettuce outdoors. Until then I’ve been growing and harvesting small batches of micro-sized greens on my windowsill as a way to keep some salad fixings coming through the darkest and longest days of winter.
Microgreens are tender and tangy lettuce and mustard greens that are chopped off young, usually when they are only an inch or so high at the most and barely a few weeks old. They’re smaller and younger than baby greens, which tend to be harvested later when the plants have grown a good three inches tall or more.
It is this short growth span that makes microgreens possible to produce on even the darkest windowsills through the dingiest months of the year. Even the most beginner seed starter can take this growing project on since the plants only need to be kept alive for a few weeks tops. Unlike growing full-sized plants, it’s not the end of the world if they grow a little leggy (thin and stretchy) in the process.
Lettuce Greens to Try
Give yourself a break on the first time out by growing readymade storebought mixes that come in mild or spicy combinations. Some companies sell mixes that include the word microgreen on the package but any salad or mesclun mix can be grown this way. I like Urban Harvest’s Oriental Salad Mix (has a slight kick) and the Mild Mix prepared by Botanical Interests. Once you’ve got a taste for what you like try making your own mixes. It’s more cost effective and you can tailor make mixes that leave out any greens that don’t suit your taste buds.
Spicy: Peppergrass cress, ‘Giant Red’ mustard, radish, arugula, daikon radish, and ‘Wrinkled Crinkled’ cress.
Mild and Tangy: Tatsoi, mizuna, kale, lettuce, miner’s lettuce, and minutina.
How to Grow
They’re not particularly attractive, but I grow mine in recycled plastic takeaway containers and clamshell packaging. They’re always on hand and tend to be the right size for the windowsill. To prepare, simply punch 5 or 7 drainage holes (I always go for odd numbers) into the bottom of a 9″ x 7″ package using an awl, sharp pair of scissors, or knife. Fill ‘er up with well-moistened container mix, potting soil, or seed-starting mix to within an inch or so from the top. Evenly distribute a thin layer of seeds, sprinkling them over the soil surface with about 1/8″ to 1/4″ of space between them. Cover the seeds with a thin layer of soil, about 1/8″ deep. Set it in the sunniest window you’ve got with the lid of the clamshell placed underneath as a drip tray. Water in well to get them germinating.
Sprouts at about the one week mark.
Keep the soil moist like a wrung-out sponge but not soaking wet. To avoid over-watering, dunk out any water that is still in the drip tray within an hour of watering. Microgreens can be harvested with a pair of scissors in 1 1/2-2 weeks depending on how large you want to grow them. I generally let mine grow until the moment their first set of “true leaves” begin to peek out. The first leaves you see are called “seed leaves” since they are actually a part of the seed. “True leaves” are the second set to appear and often look very different than the seed leaves.
Starting Again
Unfortunately, unlike when growing baby-sized and mature greens, you can not grow a second crop from the same stems. This is because the plants you are harvesting are essentially sprouts. Second crops grow from the upper part of the stem above the leaves, and these are harvested on the lower part of the stem below the leaves. The bad news is that you will have to start over with fresh seeds to produce another crop. The good news is that you can reuse the pot and soil if there were no problems with disease or pests on the first go-around.
To prepare for another crop, simply yank the remaining roots and stems out of the soil, toss them in the compost bin, and till the remaining soil with a fork. Sprinkle on a fresh layer of seeds, top it with a thin layer of soil and the process is begun anew.
Start a second crop of microgreens a few days to one week after the first set and you’ll have continuous crops ready for harvest through the winter.
