How to Grow Microgreens Efficiently Indoors

Reader Contribution by Kevin Espiritu
Published on November 12, 2018
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If you haven’t heard of microgreens…you’re in for a surprise! These plants are nutritional powerhouses and can be grown anywhere, even if you’re living in the smallest of apartments!

But first…what are microgreens? It’s actually pretty simple: Microgreens are normal plants that are harvested at the 8-21 day range, depending on the variety. They’re even smaller than baby greens, typically only grow to their first set of true leaves.

I love growing microgreens for their nutrient density. They make an excellent addition to a morning green smoothie or a quick and easy salad. Better yet, even brown-thumbed gardeners can grow them with ease!

Photo by Mary Jane Duford

Here’s what you’ll need:

  • Microgreen seeds
  • Potting soil
  • 1020 propagation trays
  • Spray bottle

You can use normal seed packets if you want, but microgreens are seeded much denser than a normal crop. I typically buy my seeds in bulk from a few different online suppliers. When starting out, I recommend growing simple leafy greens like arugula, radish, lettuce mixes, or kale. These are all harvested in under ten days and produce a large yield of microgreens.

Fill a 1020 propagation tray with 2 cups of water. Then, add your potting soil, about 1/2-inch below the brim. Leaving this space makes it easier to harvest your crop without pulling up a lot of dirt. We add the water first to make it easier to fully soak your soil, instead of top watering and potentially creating a soggy mess.

Make sure your soil is level in the tray, then measure out about 1-2 ounces of microgreen seeds. As a rule of thumb, the larger the seed, the more you’ll need to plant by weight. For example, arugula can be seeded at 1 ounce per tray, whereas larger radish seeds require around 3 ounces per tray.

Surface sow your seeds, then give them a light misting with your spray bottle. Next, take your other 1020 propagation tray and flip it upside down on top of the first tray. This tray acts as a “blackout dome” that will simulate burying your seeds below the surface of the soil.


Photo by Kevin Espiritu

At this point, the hard work is done. It’s time to let your seeds germinate. Most varieties take 2-4 days to germinate. Every day during the “blackout” phase, take the top tray off and check on your seeds. You’ll want to look for a few things:

  • Is there enough moisture? If not, give the tray a spray with your spray bottle
  • Is there any mold or fungus on the surface? If so, remove the blackout dome early to try and lower humidity
  • Are your seeds beginning to germinate?

After five days, your seeds will have germinated and begun reaching for the light…only there is no light! It’s time to remove the blackout dome and expose them to the sun. They’ll be yellow and a bit spindly looking, which is completely normal. They haven’t been able to photosynthesize yet. In a day or two of sun exposure they’ll green up and start growing.

At this point, it’s up to you when you want to harvest. The cotyledons, or seed leaves, are the first set of leaves that appear. After that, the first set of “true” leaves appear. This is a fantastic time to harvest, as the microgreens are still young and nutrient-dense. Any longer and you’re crossing over into the baby green territory.

When harvesting, use a sharp, sterile pair of scissors and cut about 1/2-inch above the surface of the soil. Take care not to pull up any dirt or seed hulls — this makes cleaning your microgreens a pain. Washing microgreens can be done, but it’s unnecessary if you’ve harvested in a clean fashion. Washing typically reduces the shelf life of refrigerated microgreens by about 25 percent, so avoid it if you can.

Microgreens are one of the simplest and easiest plants you can grow, and as we go into winter there’s no better edible to experiment with. You can grow them on a tiny little shelf in your bedroom, on the back patio, or in a kitchen windowsill. Experiment with a few different varieties and methods until you settle upon your favorite microgreens for salads, soups, smoothies, and more!

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