QUESTION: What is the best growing medium for microgreens? I was looking at all the options and I’m a little overwhelmed. – Jules E
GARDENING CHANNEL REPLIES: It all depends upon your goals when growing microgreens as to which growing medium may work best.
Many gardeners say that vermiculite or perlite mixed with coco coir or peat moss are your best options. The reason being is these ingredients are known for creating an environment with good drainage and aeration.
However, some gardeners feel that properly amended soil is the better option as it’s the easiest for setting up a growing location quickly and produces a greater harvest.
To help you make an informed decision, here are a few things you should consider when picking the growing medium which you feel works best:
1. Consistency of the Growing Medium
When you’re selecting a growing medium for microgreens, it’s vital that these small, fragile plants are growing in a location which allows them to easily press down into the soil to develop a strong root system.
This scares many people away from traditional soil as some soil types are heavy and compacted. Therefore, if you choose soil, ensure you amend it to encourage a loose, light growing medium that’s aerated and drains well.
If you take the time to amend your soil it should make it easier for the plants to dig into and also deter the soil from becoming compacted.
Again, this will boil down to personal choice as there are soil-less options (stated above) that can create a light, loose growing environment that allows the microgreens to dig in and form strong roots.
Much of this decision may boil down to resources available in your area and your budget for growing microgreens.
2. Consider Disease
You want to choose a growing medium that will deter issues with disease, when possible. This is another reason why some gardeners choose to go with soil-less growing mediums as fungal diseases have a difficult time forming where there’s no soil.
Also, these growing mediums are known for their adequate drainage which makes it hard for fungal issues to form since these diseases grow in areas which are consistently cold and damp.
However, should you choose to grow in amended soil, you may avoid disease by sterilizing the soil first. You may do this by placing your soil on a cookie sheet and placing it in your oven. The heat should kill off any spores which are hiding in your soil waiting for their chance to develop into something more.
You can also set your soil outside in the sun under a black tarp for a few weeks, during the warmer portions of the year, to sterilize it.
When picking the right growing medium for your microgreens, take steps to consider how you can protect the plants from disease before the seeds are ever planted.
3. Don’t Forget Growing Mats
The last thing to consider is growing microgreens in a growing mat. You do this by picking your mat material, cutting it to the size of your growing tray, and placing it in the bottom of the tray.
Dampen the growing mat, sprinkle your seeds over it, and ensure the mat never fully dries out. Mats are a great option for growing microgreens since most people grow their greens indoors.
However, should you use a growing mat outdoors, check the mat more frequently. Outdoor conditions tend to dry growing mats out faster.
Do keep in mind, it’s difficult to reuse growing mats as the roots of the microgreens become ingrained in the mat. Frequently, the microgreens must be cut away from the mat which destroys the growing medium in the harvesting process. However, you may still compost the mats for later use depending upon the material they’re made from. Many mats are made from hemp or coir which is a compostable material.
As you can tell you have a few options for growing microgreens. Depending upon your overall gardening goals (i.e., sticking to a budget, being environmentally friendly, producing a large yield, etc.) will determine which growing medium is best for your situation.
The good news is you have quite a selection between soil-less growing mediums, amended soil, and even growing mats. Consider your goals when growing microgreens, take these tips into account, and make the selection which best supports your goals.