The Best Soils For Germinating Cannabis Seeds

Germinating cannabis seeds can be a scary process, one mistake can lead to non-germination, and when that occurs we, as growers, immediately lose money on what was supposed to be an investment into our grow.

We’ve handled thousands of customer queries over the years and the medium used for germination is a common cause of issues. Soils that are too compact can easily drown our plants and stifle root development, while those with excessive bark may be prone to burning and killing young seedlings.

This guide aims to reduce these issues and in turn, give you better germination rates. But before we dive into which soils we recommend, I’ll run through some essential soil knowledge for every grower, advising which common mistakes to avoid.

Avoid Potting Soils With A Lot Of Bark

If you’re buying soil from garden stores, be careful not to buy traditional potting soil that includes a lot of bark, as these soils often have three main problems.

• Acidic (low) pH that locks out nutrient uptake.
• High EC (“hot soils”) can burn plants.
• Lack of nitrogen uptake due to uncomposted bark.

The symptoms of these potting mixes are quite uniform and we’ve noticed a number of customers buying Cultera potting soil and encountering these issues. Having organic matter in soil is great, but it needs to be properly broken down or balanced with the rest of the mix. It also needs to have a pH range that facilitates the uptake of nutrients.

Avoid these potting soils at all costs.

What To Look For In A Quality Seed Starting Soil

If you’d like to explore other brands outside of this list, it will be helpful to understand the qualities that make seed-starting soil good. Here’s what you should look for:

• Aeration and moisture balance (typically achieved through a balanced blend of Perlite and Vermiculite).
• Low pathogens and low amount of pests and vectors.
• Good drainage.
• Fluffy/Not too dense.
• Balanced pH between 5.7 and 6.5.
• Optimal nutrient levels (hot soils can burn seedlings).

So, What Are The Right Soils To Use For Germination?

The good news is that there are several quality cannabis soils available around South Africa, and some are now even stored at traditional nurseries. However, hydro stores tend to offer better prices and also usually have fewer pest problems, as these bags are often stored around other plants in garden shops while hydro stores tend to be cleaner. Here are some of my favorite soils for popping beans.

Freedom Farms Seedling Mix

Specifically designed for cannabis seed germination, the Freedom Farms Seedling Mix features a coco-coir dominant base with perlite and vermiculite to balance moisture levels, with additional amendments, including pathogen and pest control. The additional organic amendments help give the young seedlings steady access to essential nutrients during the early stages of life, meaning you don’t need to feed the plants immediately and can use water only for the first week or two of growth.

Freedom Farms Classic

Freedom Farms classic is a little hotter than the seedling mix, but can still easily be germinated in. This soil has been a staple in the South African cannabis community for more than half a decade. Freedom Farms classic is a great choice for ‘synthganics’ where salt-based nutrients are fed to plants in soil, instead of in a pure coco/perlite mix. It also does well with pure organic growing and remains one of the most popular soils in the country.

It is built around a coco-coir base, with a lot of additional amendments that help to keep plants happy and reduce the amount of direct feeding that’s required. The fluffy, aerated nature of Freedom Farms classic makes germination forgiving, creating a small buffer around overwatering.

Organics Matters

Organics Matters is a premium craft soil blend that has always been centered around a fully organic approach to gardening. While Organics Matters is packed full of nutrients, this rich soil tends not to give many problems for seed starting, and in my time using this soil, I had good germination rates, even without cutting the soil with perlite to reduce its concentration of amendments.

Organics Matters differs from most other brands in that they don’t use typical coco coir fibers and instead make use of coco peat coir, a finer type of coco that has more water retention than others. It also includes Sphagnum Peat Moss, which also aids in water retention. If you’re prone to underwatering your cannabis plants, this can help improve your germination rates. However, because it holds onto water more, it can be slightly more prone to overwatering issues.

If you’re using large pots or beds and plan to do a fully organic run, then Organics Matters may be exactly what you’re after.

Orgasoilux + Coco/Perlite Mix

By itself, Orgasoilux is a hearty and strong mix for cannabis plants, but some find that it’s a little too much for some sensitive seedlings so they cut the soil with some additional coco coir and perlite for germination. I’ve used this soil extensively and have had a fairly good germination rate with it, even without the mix. However, there are more large organic elements in the mix and it performs best as an organic soil, especially in the outdoors. Similar to Organics Matter, Orgasoilux uses Sphagnum peat moss alongside coco peat.

For seed germination, to get the most forgiving experience possible, I’d recommend mixing 10L of soil with 5L of coco coir and 1L of perlite or using an 80/20 coco/perlite mix at a ratio of 1:2.

At this ratio, there is still some nutrient availability for the first week or two of the seedling phase, but then I recommend potting it up into the normal Orgasoilux blend. Given that it’s somewhat heavy soil, one should be careful not to overwater if you decide to germinate directly into the Orgasoilux mix.

Conclusion

With dozens of different soil blends on the market, it can be challenging to know how to start your cannabis seed journey. Many new growers, excited by their new seeds, rush to buy soils from garden stores only to end up disappointed by the results and in some cases are left puzzled by what happened.

Different plants enjoy different soils, and what works for roses may not work for cannabis. As such, there are a few tried, tested, and popular brands that are specifically formulated with cannabis in mind. These are the types of soils you should look at buying.