You can use potting soil to grow microgreens. Growing with potting soil is a proven method for growing abundant, healthy microgreens because they have the correct aeration and nutrient ratio, are decontaminated, and renewable. Use a microgreen specific potting soil that consists of a sandy loam soil that is OMRI certified, ready to use, properly aerated, great at retaining water for chore efficiency, and free of animal products or by-products.
The following article answers some of the most common questions about the soil necessary for growing microgreens, along with a few tricks of the trade.
What should I look for when picking out a potting soil for microgreens?
According to True Leaf Market, leaders in microgreen seed production, when buying potting soil to grow microgreens you should look for a brand that is OMRI certified, ready to use, properly aerated, great at retaining water for chore efficiency, and free of animal products or by-products.
What is the best soil to use for growing microgreens?
You can use any potting soil, but it is best to stick with those meant for seed starting because some potting soil nutrient ratios may be too hot, causing damage to the microgreen seedlings. There is also a potting soil that is specifically designed for growing microgreens.
What is so special about microgreen specific potting soil?
Microgreen specific potting soil is a sandy loam soil with a balanced pH that has finely ground soil particles to help grow the petite plants. It lacks the ingredients that potentially cause contamination, such as bone mean and coop poop. And, it has the perfect perlite, compost, worm casting, and coco coir ratio that is designed for the optimal growth of microgreens.
What are the key ingredients in microgreen potting soil?
Each company is going to have their own blend of ingredients within their potting soil, but the main ingredients stay consistent across the brands.
The key ingredients in microgreen potting soil include:
- Peat moss – For water retention
- Coconut Coir – For water retention
- Perlite – Facilitates aeration through water drainage
- Organic Fertilizers – To provide nutrients
- Limestone – To balance the pH
Do you need to use fertilizer to grow microgreens?
You do not need to use liquid fertilizer if you are using the appropriate potting soil. This is good because liquid fertilizers often contain chemicals and added ingredients that are not organic and not necessary to add to your edible products.
What can I use instead of liquid fertilizers?
Instead of feeding your microgreens liquid fertilizers, you can use solid fertilizers, such as soil amendments, that you add to the soil before planting. Amending your soil is easy and cost effective, but it should only be necessary when the soil nutrients have been depleted by previous crops. Otherwise, a seed starting type of potting soil should be ready to use and have everything that you need to grow microgreens right out of the bag without amending it.
Can I reuse my potting soil for microgreens?
You can reuse your soil a few times before amending the soil is required. Microgreens are getting most of their nutrients from the soil, so as you reuse the soil it depletes those vitamins and minerals. Amending the soil is easy to do and costs less than consistently buying new soil.
Some of the soil amendments can include:
- Kelp meal
- Neem meal
- Alfalfa meal
- Rock Phosphate
- Green sand
- Humic acid
- Worm castings
How long do microgreens take to grow?
Depending on the type of microgreen you are growing, it can take anywhere from 8 days to several weeks. Anything grown beyond that time frame would typically not be considered a microgreen because it has grown beyond the cotyledon stage. Radish microgreens are some of the fastest growing, with a harvest being ready to eat in only 8 to 12 days; while cilantro microgreens can take between 21-28 days to be ready to harvest.
Can I use compost manure to grow microgreens?
It is not recommended to use compost manure as a growing medium with edible leafy greens because it can carry bacteria that can cause digestive issues. That is also why washing your microgreens before eating is highly recommended. You can add a high-grade sterilized compost to your soil mix as a fertilizer, but in most cases, it is already included within a potting soil mix.
Can I use the topsoil in my yard to grow microgreens?
You can use the topsoil from your yard to try to grow microgreens, and you may have luck growing a small batch; but natural topsoil lacks aeration and can contain microorganisms, bacteria, or weeds that you wouldn’t want to add to your microgreen salad.
Why is potting soil better to use than topsoil?
Potting soils come with aerations techniques such as the use of perlite, vermiculite, and peat moss. Potting soils are also typically pasteurized or sterilized to reduce the risk of contamination to your plants.
Some of the things that can be contained within natural topsoil include:
- Nematode worms
- Insect larvae
- Rot fungi
- Weed seeds
Can I grow microgreens without soil?
Some of the non-soil type microgreen growing mediums include:
- Cloths made of natural fibers like coconut coir
- Burlap made from jute
- Bamboo or straw pads
- Synthetic foam pads of woven plastic
- Rock wool
- Volcanic cinder
- Crushed granite
- Inland sand
Is it better to grow microgreens with the soil or soilless method?
Using the soilless method decreased the mess and time during planting, which can increase chore efficiency. But research has shown that hydroponic methods may not be more productive, due to the need to use added fertilizers and increased risk of mold growth. Growing microgreens with soil is a proven way to get a healthy and abundant product without using liquid fertilizers, mold inhibitors, and massive amounts of water.
Hi, I’m John Stephens, chief editor and writer for Totalgardener.com. I’ve been gardening and raising animals for over 15 years starting with a small backyard plot in Northern Virginia where I grew corn, potatoes, squash, and using a high mulch technique called the Ruth Stout Method. I also raised ducks and small mammals for meat and eggs in a movable pen similar to the ones used by Joel Salatin. I later moved to Colorado where I experimented with growing greens using aquaponics inside. I eventually added a microgreens setup and home sprouting operation. I’m excited to share everything I’ve learned plus more from the other local gardening and animal raising experts I know.