Worm castings and their properties

  • Worm castings are a great ally for growers who choose to feed their plants with organic fertilisers.
  • They are an organic form of fertiliser that is becoming increasingly popular due to the numerous benefits that it can bring to cannabis plants.
  • In addition, it is a great way of recycling food waste and returning it to the soil in a natural and environmentally-friendly manner.
  • In this post we explain everything you need to know about this biological fertiliser and its properties.

What are worm castings?

Worm castings are an organic and eco-friendly type of fertiliser based on waste from Californian earthworms. It is one of the most powerful biofertilisers on the market, as these red worms contain a peculiar mix of enzymes and beneficial bacteria in their digestive system which greatly contributes to the development of cannabis plants.

In the same way that humans take probiotics such as Kombucha tea or kefir to help them balance their intestinal flora, plants can also benefit from a soil rich in these elements. This 'worm poo' promotes vigorous growth and resistance to diseases and pests, as well as soil oxygenation.

The technique used to make worm castings is called vermiculture or vermicomposting. The most commonly used worms in this process are a type of Californian red worms called Eisenia foetida. However, other species can also be used, including Eisenia andrei, Dendrobaena veneta, Eudrilus eugeniae, Perionyx excavatus, and Pheretima hawanya in the tropics.

As mentioned above, this process is simple: the worms feed on the nutrients found in food scraps and other compostable matter. In fact, the reason why these worm species are chosen for the job is because of their great appetite, which helps accelerate the composting process.

What nutrients are found in worm compost?

Worm castings are one of the most recommended fertilisers for cannabis growing. If your plants could talk, they would surely beg for worm castings. Many of the nutrients required for cannabis to grow to its full potential are found in huge concentrations in this type of substrate. Worm castings are rich in:

  • Magnesium
  • Calcium
  • Potassium
  • Phosphorus
  • Copper
  • Zinc
  • Iron
  • Cobalt
  • Boron
  • Manganese
  • Nitrogen
  • Carbon

Although there are other substrates that also contain these nutrients, the great advantage of worm compost is that it does not burn the roots, so you will not need to worry about having added it to your soil in excess.

Another advantage of worm castings is the fact that they dissolve in water more easily, which means that plants can absorb them more quickly. Therefore, it is very unlikely that your cannabis plants will be lacking in nutrients, which is something that would otherwise be a real nightmare for growers.

What are the benefits of using worm castings in cannabis growing?

If you are still not convinced that worm castings are 'the bee's knees' for growers, here are even more reasons to start practising the science of vermiculture:

  • It enhances plant productivity.
  • It can contain a great range of nutrients and it can be applied to any cannabis strain as well as to different types of soil.
  • It promotes plant development as it helps with the absorption of some elements such as magnesium and potassium.
  • It shows high levels of beneficial macrobiotic elements.
  • It facilitates rooting.
  • It strengthens plant immunity; this is why it is advised to apply it when the plants are under stress, for instance during transplantation.
  • It prevents plant dehydration as it increases the ability of the soil to retain moisture.
  • It protects marijuana plants against fungi and diseases.
  • It is made from 100% organic ingredients.
  • It enriches the soil, making it more fertile.
  • It enhances soil oxygenation.
  • Unlike other fertilisers, it does not contain any heavy metals like lead or cadmium, as worms have the ability to absorb them.
  • They do not burn the plants' roots.

How to apply worm castings?

Worm castings are a truly versatile fertiliser and, depending on your needs, there are different ways of using them. These are my personal suggestions:

  • Mixed with soil: this is one of the best application methods. If you are going to start your grow from scratch and want to prepare a nutrient-rich soil, add one part of worm castings for every three parts of soil.
  • As a top dressing: if your plants are already in the soil and you want to give them a nutrient boost, you can scatter worm castings over the soil, which will seep into the ground when the plants are being watered.
  • Worm compost tea: another way of adding this biofertiliser to your crop is by making an infusion with water, molasses, and worm castings. You can spray this tea over the soil, the plants, or both. If this is applied every so often it will protect your plants from pests and fungi.

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