Potting soil for auto-flowering plants: a guide to choosing the appropriate one

Choosing soil for auto-flowering hemp plants

Modified on: 20/09/2022

Practical tips for choosing (or creating) the perfect substrate for auto-flowering hemp plants

In hemp cultivation, auto-flowering hemp plants are usually referred to as the easiest and quickest to grow.

These plants indeed require less maintenance than photoperiodic hemp varieties, but this does not mean that you can leave everything to chance when growing them.

For example, a great deal of attention must be paid to the choice of substrate, the source of nutrients that determine all plants’ successful and optimal development.

Would you like to know the secrets of the best soil for auto-flowering plants?

Curious as to why it is essential to pay attention to specific characteristics?

In this article on our SensorySeeds blog, we will talk about the importance of deciding the appropriate soil when planting cannabis seeds and how to create the ideal mix for a successful harvest!

Potting soil for auto-flowering plants and tools

Substrate for auto-flowering plants: Why choose ‘light’ soil and create it?

Experienced cannabis growers know that hemp plants grown from auto-flowering seeds have different needs than periodically growing plants, even when it comes to soil.

To grow at their best, it is significant to grow auto-flowering plants in light, well-ventilated soil and pay attention to the number of nutrients it contains.

Soil that is too ‘heavy’ tends to block the expansion of the roots, which cannot access the appropriate amount of air and thus prevent the plant from developing correctly.

To control both aeration and nutrient content, hemp growers say that the best way is to use self-made soil.

A suitable ‘recipe’ might look like this:

  • 1 part vermiculite (preferably previously wet);
  • 2 parts perlite (also previously wetted);
  • 3 parts compost;
  • 2 parts peat.

Other canapiculturists, however, prefer a mix like this:

  • 1 part vermiculite;
  • 1 part coconut fibre;
  • 1 cup vermicompost or humus;
  • 2 parts compost.

These are just two examples of ideal mixes, and they are not the only ones; the important thing is to get a substrate that is soft enough, drains well and is nutritious enough to allow the auto-flowering plants to develop at their best from root to top.

Read also: Can you be allergic to cannabis? Here is the answer

Fertilisers in soil: Here’s why it’s best not to overdo it

If, at this point, you are wondering why compared to photoperiodic plants with auto-flowering and dwarf auto-flowering, it is particularly significant not to exaggerate the number of fertilisers. The answer lies in their small size and rapid development.

Hemp plants of this variety go from one development phase to the next quickly, so giving them the amount of fertiliser you would provide to classic photoperiodic plants would not give them time to absorb it. As a result, they would end up burning (nutrient burn).

In particular, care must be taken not to overdo the nitrogen doses; during the flowering stage, it may be sufficient to add just miniature bat guano to the substrate.

Autoflowering cannabis bud in the perfect substrate

Substrate pH for auto-flowering plants—what’s important to know

As well as paying attention to the composition of the substrate and avoiding over-fertilisation, pH levels need to be constantly monitored to grow the best auto-flowering cannabis plants.

Auto-flowering varieties prefer slightly acidic soils, so cannabis growers usually keep pH levels between 6.2 and 6.5.

If you find that the pH is too low or too high when using the soil, you don’t have to replace it, fortunately, but several products on the market can correct it.

Read also: Hemp and sun exposure: is direct sun recommended?

In conclusion

In this article, we briefly talked about how important a well-balanced, quality soil is for the optimal development of auto-flowering plants.

It is essential to use a light substrate, as too hard a one will prevent the roots from developing correctly and getting enough oxygen, which will weaken the whole plant. At the same time, attention must also be paid to nutrient levels and pH.

We would like to remind you that the cultivation of cannabis is not permitted 

(unless you have authorisation) and that this article is for information purposes only.

Before saying goodbye, if you love the cannabis sector and particularly like collecting seeds from the best genetics, we invite you to visit our online store Sensoryseeds.

Choose from our wide range of quality weed seeds to complete your collection: feminized seeds, auto flower seeds, fast growing weed seeds, there is something for every taste! 

We look forward to seeing you on Sensoryseeds.com!