Score: 4/5


Espoma is a company that has been producing solely organic gardening soils and fertilizers for some 90 years, so they have a long-standing experience in organic soils that you can trust. Their Espoma Organic Seed Starter mix is no exception: it is an excellent organic seed-starting soil, great for your seedlings and cuttings.

When you grow seedlings from seeds, you need a light, well-drained soil that retains water and supports the growth of roots and protects the seedlings from disease. Regular potting soil may be too coarse and heavy, as well as unnecessarily rich in nutrients (seedlings get everything they need from the seed itself).  Seed-starting soils are finer and lighter, drain more, and often come sterilized to protect the delicate seedlings from disease and fungi.

The Espoma Organic Seed Starter tics all the above boxes. Its main base, at more than 80%, is peat moss. The mix is enhanced with perlite, lime, and yucca extract for drainage and water retention. Most importantly, it is full of Myco-tone, a blend of mycorrhizae that helps seedlings grow solid roots.

The blend is pre-mixed and ready to use straight out of the bag. The 8-liter bag is priced at a little more than $15, which is expensive compared to other seed starting soil mixes. However, many growers find it a particularly efficient mix at germination. So, if you can afford it, it is worth it.


Base and Composts

The Espoma Organic Seed Starter contains a nice blend of natural ingredients that make it light, soft, and rich in organic matter. 80-90% of its base consists of finely ground sphagnum peat moss, which can retain up to 20 times its weight in water, thus keeping the seedlings hydrated and preventing the soil from drying too fast.

The mix does not contain compost or fertilizers, but this is normal for seed starting soils: the seeds themselves contain all the nutrients the seedlings need, so compost and fertilizers are of no use at this point and can even harm the fragile roots of the seedlings. Drainage and aeration are more important at this stage of the plant growth, as is supporting the growth of vigorous roots first, then sprouting and germination.

Aeration and Drainage

The Espoma Organic Seed Starter has a fine, light texture that allows for good aeration and drainage. This is due to the addition of perlite in the blend.

Perlite is a volcanic mineral, thus a natural ingredient, that adds aeration to your seedling mix by making the soil looser. The growing, fragile roots of your seedlings need light soil to push through, therefore perlite is an essential addition to the seed starting soil. Also, by creating space between the particles of the soil, perlite allows more air around the roots of the seedlings, while it retains water and improves drainage at the same time.

However, the mix used to include peat humus as well. This has now changed and the mix now only includes perlite.

Mineral Additions

The Epsoma Organic Seed Starter includes dolomite limestone. Dolomite limestone contributes to plant development and general health by bringing calcium and magnesium to the mix. It is also used to counterbalance the acidity due to peat moss and to adjust the blend’s pH.

Soil Amendments

Probably the most important ingredient of the Epsoma Organic Seed Starter is Myco-tone. This is Espoma’s proprietary blend of endo and ecto mycorrhizae, fungi that have been proven to promote root growth, increase water uptake, and reduce drought stress and transplant shock.

The blend contains 5 species of ectomycorrhizal fungi (Pisiolithus tinctorius, Rhizopogon luteolus, Rhizopogon roseolus, Scleroderma citrinum, and Scleroderma verrucosum) and 4 species of endomycorrhizal fungi (Rhizophagus irregularis, Septoglomus deserticola, Claroideoglomus etunicatum, and Funneliformis mosseae). These nutritional fungi grow symbiotically with the roots of the seedlings and act as an extension of the plant’s root system, increasing its capacity to reach water and nutrients.

The mix used to contain worm castings. However, it now contains another soil amendment instead: yucca extract. Yucca extra protects in multiple ways the delicate seedlings. It contains saponins, which are natural foaming agents that have anti-microbial, anti-fungal, anti-oxidant, and anti-bacterial properties.

Furthermore, saponins are a natural wetting agent. They break the surface tension of liquids and allow them to be better distributed in the soil and absorbed by the plant. In simple terms, the yucca extract increases the capacity of the roots to absorb water and nutrients from the soil, while protecting them against bacterial and fungus pathogens, drought, heat, and salinity.

Quick Summary—Pros and Cons


  • Made by a reputable company known for its high-quality products.
  • Contains myco-tone and yucca extracts, which help the roots grow quickly and vigorously.
  • Is perfect for organic farming and only uses natural ingredients.
  • Is ready to use straight out of the bag.


  • More expensive than some other seed starter soils on the market.
  • Can contain little pieces of wood, which some growers prefer to pick out of the soil.
  • While the mix is excellent for generic use, the addition of dolomite limestone may make it more balanced than some cannabis growers might prefer (depending on their soil’s and water’s pH).

 More organic soil reviews