How I Grow Microgreens Indoors

How I Grow Microgreens Indoors

Fresh leafy vegetables can be a big part of a healthy diet, but can also be costly. Not only costly, but after being shipped long distances, they may not even be that fresh.

Square foot gardening is a really popular answer to that problem. And it can make gardening simpler, but even then, not everyone has the time and space.  I’m going to be talking about a square foot garden of sorts in this article. A one square foot garden.

Microgreens can be grown from the seed of many of the same vegetables you buy at the farmer's market.  They are simply harvested in the beginning stages of plant growth. The seed contains all the nutrients it needs to go through the initial stages of growth, so microgreens are very nutritious and easy to grow.

They can never completely replace vegetables, because they simply don't have the fiber your body needs.  But they can be a great way to put some extra vitamins, minerals, and antioxidants in your diet.  

I've been growing microgreens in my home for two years now. I'm going to take you through my process, and maybe you'll pick up some new tips to help you grow more efficiently.  I've tried to break the steps down into simple tasks that are hopefully easy to follow.

Materials You'll Need

Jiffy seed starting mix, jiffy greenhouse kit, seeds, watering can, bottle sprayer, cutting shears
  • Seed.  Lots of choices here. One of my favorite part of microgreens are all the new things you can grow that you may not have been able to previously. Here are some of seed companies that sell microgreen seeds in bulk but stick to their microgreens sections for choices that are easy to grow and safe to eat.

    The small packets at your local gardening store aren't going to get you very far.  They will work, but I would encourage you to buy seed in bulk because you use a lot in microgreens. 1 ounce packets are a good start for small seeds like kale, spinach, and broccoli. 1/4 pound for bigger seeds like sunflower and pea shoots.

  • Container. You don't need anything large here, some people plant microgreens in cupcake wrappers. You're looking for something that is ideally shallow since microgreens don't need a lot of soil. I like Jiffy Greenhouse Kits because they are a good value and easy to find.

    Something with drainage holes is optimal. If your container does have drainage holes, look for a tray large enough to put it in. I have other ideas in my containers section.

  • Soil.  You need a light, sterile soil. Don't know what any of that means? Choose a seed-starting mix in a more trusted brand like Jiffy, Espoma, or Burpee. Should be around $6 for 12 quarts of soil. For most microgreens, you do not need fertilizer.

  • Light. A sunny windowsill or a  will work fine.

  • Scissors.  Scissors or a sharp knife will work here, so if you don't have one of these, pick some up.  I like scissors for the safety aspect, but a knife can get the job done faster. (ex.Hydro Crunch 6.5 in. Gardening Hand Pruning Shears)

  • Spray bottle.  This will help keep your seeds hydrated. Make sure it sprays a fine mist.   

Start Planting

microgreens in a 5x5 container under an LED light
  1. Make sure your container is clean. The humidity needed to germinate and grow seedlings also help mold and disease grow too. Reusing containers can turn a small unnoticeable problem on the last harvest into a big one.    

  2. Fill your container with your seed-starting mix and lightly press it to create an even surface. As you sprinkle your seeds on the soil, you want them to spread evenly.

  3. Add a tray. If your container has drainage holes, put it in a tray (without drainage holes) to catch excess water or to use to bottom-up water your seedlings (explained below).

  4. Lightly water the soil. Note how your soil looks before and after watering so you'll be able to more easily tell if it needs water later. Your soil should soak up the water.

  5. Spread your seeds on top of the soil. You'll want cover the surface of the soil with seeds. You should barely be able to see the soil under it. As long as you have a cover to hold in humidity, you should not have to cover the seeds with soil.    

  6. Mist the seeds evenly with your bottle sprayer.  

  7. Put your cover on.  This holds your moisture in and help germination.  If you bought a greenhouse kit, you have this step “covered”. Plastic wrap or another container placed upside-down could also work.

  8. Choose your placement wisely. Light and temperature will be important factors.  Windowsill light will work, a grow light will produce better results for some crops. Soil is a source of contamination, so placement near food preparation or eating areas is not recommended.

  9. After your seeds germinate, take the cover off.  This should take between 1-3 days on average. I usually take the cover off a couple of days after the seeds germinate.  

Daily Maintenance

Watering

Check your soil to test how much water is available to your microgreens. If you touch the soil, does it stick to your hand? If not, then some water might be necessary. 

Microgreens are fragile, and will sometimes fall over if you drench them from above with your watering can (top-down watering). The bottom-up watering method can help control getting the microgreens the water they need as needed. If your container has drainage holes and is in a tray, your already prepared. Bottom-up watering can be more convenient, keep your microgreen leaves dry and an overall better way to water.  

The bottom-up watering method

To bottom-up water, make sure your planting container has drainage holes.  Then, put your planting container into a larger container or tray without any drainage holes.  Put water into your tray (not the planting container) and allow the soil in the planting container to soak up this water. I leave it for about an hour and pour the rest of the water out of the tray. The container shouldn't sit in water for an extended period of time. 

Air circulation   

Humidity can be your friend when germinating your seeds, but afterwards not so much. Soil and air that is too wet breeds disease, soil gnats, and other things you don't want. If your microgreens are in an area that doesn't get much air circulation through your A/C unit or otherwise, you may want to consider putting a small fan in the area just to give them a gentle breeze for part of the day.

Temperature

Most seeds need a higher temperature to germinate than they need to actually grow.  A good basic temperature for seed germination is 70F to get good germination rates. If your room is regularly kept at 70F, the soil temperature could be much lower. Your light source should help with heat. But if you are having problems getting your seeds to germinate, temperature could be the problem. You can get a heating mat to help.

Harvesting

sauteed pea shoots
  1. Your seed store should have guidelines on when to harvest.  In general, when they are at least 2-4 inches tall, which can occur in as little as 7-14 days after germination.

  2. The leaves and stems should be dry before storage to increase longevity. This means I don't do any top-down watering the day before harvest.

  3. Make sure everything touching the microgreens is clean (hands, surfaces, utensils)

  4. I cut an inch or so above the soil line using my scissors/shears.

  5. Remove any seed hulls, dead leaves, or soil in my harvested microgreens. I don't wash before storage to keep the microgreens dry. But other microgreens growers do suggest cleaning them immediately. If I washed them before, I would eat them sooner. 

  6. If they are wet, I try to dry them off.  Then, wrap in a paper towel.

  7. Put in a food container or plastic bag and put them in the refrigerator.

  8. Compost the soil and leftovers.  

  9. Wash before eating.

I eat them within a week of harvesting. Microgreens don't last long in storage. Alternatively, because you are growing at home, you have the option of cutting, washing, and eating immediately.

Of course, you should use common sense when harvesting.  Look for problem signs such as off-smells or the microgreens feeling slimy. Discard if something doesn't look or feel right.

I would encourage you to read more tips on preparation at FoodSafety.gov and the FDA section on produce safety.

Beyond

So, believe or not, that was the short version. There are much shorter “how to grow microgreens” articles out there, but I’ve included more specifics and things that I have learned.  

But make no mistake, this isn’t everything. Read those other articles, they may suggest things that work better for you. Part of growing microgreens is discovering what works for you. Your environment, your work schedule, your habits, and the size of your wallet can all be factors in the final “How To Grow Microgreens” customized for you. In fact, I am still improving my process even now.  

The good news is microgreens are one of the most straightforward things you can grow, so they may work when others haven’t. To go deeper into microgreens growing, I’ve broken the process into six topics you see in the right sidebar of the blog.

I also have pinned several articles that I found helpful while learning to grow microgreens on my Microgreens 101 Pinterest profile. Check it out and follow for more tips and advice on growing microgreens. 

Here are those bulk seed companies again to help get you started growing microgreens indoors.  

How To Grow Microgreens Indoors | Microgreens 101

What is a grow light?

A grow light is simply a light designed to mimic the sun.  Indoor lights like soft white bulbs put out light on the red end of the spectrum, closer to the look of candlelight. But grow lights give off full-spectrum light that is red, blue, and green. There are two main types, fluorescent and LED.