Best Soil For Microgreens: 5 Great Potting Mixes

Microgreens rely on a healthy soil environment to grow quickly and produce healthy nutritious leaves. Make sure to choose a potting mix that provides nutrients, drainage, and moisture retention to avoid any of the common microgreen growing issues. These five soils are great choices and all contain the necessary nutrients that your indoor plants will need:

*If you’re in a hurry, I’d recommend the FoxFarm Happy Frog Potting Soil as the best one. This soil is beloved by experienced and novice microgreen growers alike, and is full of nutrients that will produce several yields of healthy greens with no additional fertilizer needed.

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Best Soil For Microgreens

Soil & Microgreens 101

Black Gold All Organic Potting Soil

This potting soil is all natural and organic, making it perfect for those who want the healthiest microgreens possible. It is made in the western region of the United States and consists of peat moss, aged bark, compost, earthworm castings, perlite, pumice, and organic fertilizer. 

This soil is extremely fertile and you won’t require any additional nutrients when using it for your microgreens. Customers report that it is a smooth even blend that doesn’t contain large chunks of plant material. This makes it ideal for small scale and container gardening. 

Some have reported pest and mold problems with this soil, particularly fungus gnats. This may be caused by the added organic fertilizer. Spraying your soil with a hydrogen peroxide and water mixture will minimize this problem if you have an issue. Baking your soil (30 minutes at 160 degrees) should also correct any pest problems. 

Pros
  • Fluffy rich soil
  • All organic
  • Added compost & fertilizer
  • No large chunks in soil
Cons
  • Pest and gnat issues

FoxFarm Happy Frog Potting Soil

Happy Frog Potting Soil is an excellent beginner’s blend that provides the perfect nutrient balance to grow almost any plant. This soil is designed specifically for the container garden which means it’s perfect for your microgreens. 

FoxFarm focuses on creating a “living” soil that is full of microbes (mycorrhizal fungi) that both support and defend your growing environment. They also make sure their soil is in the proper pH range, which is important for healthy microgreen growth. 

Pros
  • Very popular brand
  • Living organisms for natural soil health
  • Balanced pH
  • Holds moisture well
Cons
  • Cons: Can be pricey

Miracle-Gro Expand ‘n Gro Concentrated Planting Mix 

Miracle Gro is a well known brand and this potting mix makes it easy for all levels of indoor growers to create healthy microgreens effortlessly. This soil comes with enough nutrients to feed your plants for up to 6 months, which means you can reuse it to create several new batches without having to buy more potting mix. 

This soil also expands up to 3 times its size when water is added to it, so it is best to moisten the soil in a separate bucket before spreading it into your microgreen trays. This compressed soil will be easier to store in an apartment or small gardening space.

This material is very fine and light with high moisture retention and a good loose structure that allows for maximum airflow. This will make sure that the root systems in your plants stay healthy.

Pros
  • Good value
  • 6 months of fertilizer
  • Compact until moistened for easy storage
Cons
  • Occasional mold issues

Espoma Organic Potting Mix

This potting mix consists of completely organic peat moss, peat humus, perlite, and dolomitic limestone. It is pH balanced and can provide an ideal environment for your microgreens. This makes it a great choice for beginner gardeners, or those working with a variety of plants who want consistent results. 

Customers have noticed germination takes up to half as much time with this fertile soil, making t a great choice for someone who wants to harvest their microgreens quickly or create large yields. Those who have transferred previously potted plants into this soil have reported a quick improvement in the health of their plants as well. 

Like most soils that are organic and aren’t sterile, there is a chance that microorganisms or pests may be attracted to the soil. You can use hydrogen peroxide or sterilize your soil through baking to minimize these issues. 

Pros
  • Organic
  • Highly fertile
  • Balanced pH
  • Good value
Cons
  • Not sterile soil (you can sterilize it on your own)

Minute Soil Compressed Coco Coir Fiber Grow Medium

This soil alternative uses compressed coconut coir fibers as a growing medium for plants.This organic material is made out of coconut shell husks and fibers. It holds water and oxygen well, is organic, and is a renewable material, making it environmentally friendly.

This potting mix is the best option for those who want to cleanly store their gardening supplies in a small space. Each soil pellet expands up to 15 times when moistened! This company has focused on creating a manageable soil option for urban gardeners, container gardeners, and microgreen growers.

Pros
  • Clean, easy & compact
  • Excellent soil alternative
  • Made out of renewable materials
Cons
  • Can be expensive

The Anatomy of Microgreens Soil

soil with small plants

There are some key factors to consider when choosing or making a soil for your microgreens. By preparing your soil to be nutrient-rich, airy, and moist, you will increase the lushness of your yields and will be able to harvest much more quickly.  

Nutrients are necessary for healthy and thriving microgreens. If your soil lacks nutrients (such as nitrogen, potassium, or phosphorus), your microgreens may “thin out” and grow slowly. In addition to getting a nutrient-dense soil, you can consider adding a fertilizer or a beneficial soil organism to your potting mix. 

Fluffy and airy soil is also helpful for growing microgreens. This helps to protect the roots and prevent root rot by making sure your plants don’t sit in stagnant water. If your potting mix is too dense, you can add some coconut coir, perlite, or peat moss to lighten it up. Make sure your containers have drainage holes as well. 

Even though we want fluffy soil that promotes water drainage, it is also important to have water retention in potting mix as well. A well-drained soil that can stay moist will create the ideal conditions for your microgreen’s root systems. Perlite and vermiculite are great additives if you need more moisture retention in your potting mix. 

How To Use Your Soil

hand holding a small plant

Select And Prepare Your Soil

Choose a soil to use for your microgreens. If you are worried about microorganisms, mold, or pests, you can bake your soil in the oven before use to make sure it is sterile. I would only recommend doing this if you’re worried that your soil is contaminated, because the heating process can reduce the benefits and nutrients present in the potting mix. You will want to heat your oven to 160 degrees and bake the soil for 30 minutes. This will eliminate fungi, bacteria, worms, and viruses. 

Saturate Your Soil

Saturating your soil before placing it in the microgreens tray will prevent a big wet mess. It also allows you to comb through your soil for any unwanted large pieces of plant material or earth. 

Pour your soil into a bucket and slowly add and mix in water. Make sure that you don’t oversaturate the soil, create pools or water, or reach a mud like consistency. As you slowly work the water into your potting mix, pick out any rocks or small twigs that you may find. 

Add Any Fertilizer Or Nutritional Boosts

It’s usually not necessary to provide fertilizer for your microgreens. Your potting mix will likely remain fertile for several batches of plants before needing a nutrient boost. However, if you choose to add it, you may experience denser and healthier yields that grow faster. Make sure to add them into the bucket and stir well for an even distribution. 

Fill Your Container With The Moistened Soil

Lift or scoop the moistened soil out of the bucket and into your microgreens container. Don’t push the soil down or condense it. Leave about a quarter-inch of space from the top of the container.

Add Your Seeds and Loosely Cover With Soil

You can soak your seeds overnight to help ensure they will sprout. When your soil is ready and in your tray, go ahead and spread your seeds evenly over all of the potting mix. Sprinkle a light layer of soil on top of the seeds. 

Soil Alternatives for Microgreens

Many people prefer using soil alternatives for their microgreens. These materials are called growing mediums, and can provide a clean, easy and effective solutions for indoor gardeners. 

Growing medium, also known as media, is essential for healthy seed starting. You can use seed starting soil as a medium, as well as several other organic materials, such as growing mats. 

There are many options when it comes to choosing a growing medium for your plants. Here is a short list of some of the most popular materials you can try.

Here are some of the most popular alternatives to soil:

Soil: Soil is the most common choice for microgreen growing as well as seed-starting in general. It is nutrient-rich and good at holding moisture for your plants. 

Coir: This organic material is made out of coconut shell husks and fibers. This material holds water and oxygen well, is organic, and is a renewable material, making it environmentally friendly. Unfortunately, it does not have great drainage, so is often best mixed with another media.

Burlap: is the most affordable choice when it comes to a microgreen medium. However, it is one of the trickiest materials to work with and may not produce ideal yields as a result of it’s difficulty. 

Rockwool: Rockwool is a sterile and porous non-degradable material that is made out of limestone and granite. It holds water very well, has great oxygen retention, and comes in a variety of sizes and shapes. Like any material, it has drawbacks as well. It is not pH neutral, creates dust particles, and can be nearly impossible to dispose of in an environmentally friendly way.

Vermiculate: This substance has great moisture and nutrient retention capacity. However, it is possible that it may hold too much water, and is an expensive choice.

Check out this article for my top picks for microgreen mediums. 

DIY Microgreens Soil Blend

DIY Microgreens Soil Blend

picture of two types of microgreens in soil

To make your own microgreens blend, you will need:

  • 1 part vermiculite
  • 1 part perlite
  • 1 part compost
  • 4 parts peat moss

This blend will provide the appropriate amount of drainage, water retention, and fertilizer for your microgreens. 

Another common method for making a customized microgreens soil is to mix 1 part of potting soil with 1 part of seed starting mix. This blend will provide ample nutrition for your plants. 

Summary

Many people choose to grow microgreens because they are simple, easy, fast, and fun. Choosing the best soil for your microgreens will provide a strong foundation for healthy and abundant yields. 

The best way to find out which potting mix, soil, or soil-free medium is best for your plants is by experimenting and finding which method works best for you. It will be worth it when you’re eating fresh healthy produce grown right in your own home! 

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