How to Use Worm Castings

  • By: Sam Richards
  • Date: August 10, 2022
  • Time to read: 5 min.

Also called vermicast, worm castings are organic solutions when it comes to fertilizing your garden. It comes from the waste left behind by worms after they eat waste materials, like veggie scraps from your kitchen and decaying garden wastes.

One advantage of worm castings is that they are rich in beneficial bacteria and microbes. They also have high humic acid content, which improves the ability of plants to take in more nutrients and enhance the health of the soil. The fact that worm castings are highly organic also makes it even more beneficial.

Top Reasons to Use Worm Castings

If you are into organic gardening, then you will surely find worm castings helpful. Here are some viable reasons why the use of this organic fertilizer is good for your garden:

  • Supplies sufficient organic nutrients – As a matter of fact, even just a single tablespoon of worm castings is already enough to feed a potted plant around 6 inches with sufficient organic nutrients for more than a couple of months.
  • Removes toxins from the soil – It extracts toxins found in your soil then turns them into something organic.
  • Protects your plants from diseases – Worm castings have humus, which is capable of fighting fungi and bacteria that may be harmful to your plants and cause diseases.
  • Improves the ability of the soil to retain oil – Note that upon application to soil, you can expect the worm castings to develop aggregates. These refer to combined mineral clusters designed to deal with water erosion and soil compaction. This results in the improved ability of soil to retain water.

Ways to Take Advantage of Worm Castings

So how can you use worm castings? Here are just five ways for you to take advantage of this organic fertilizer:

  1. Top Dressing – It is probably the easiest and simplest method of utilizing worm castings. Here, you will just have to integrate the fertilizer on the topmost part of the soil, which surrounds the plant. After that, you can make use of it by applying it to garden and potted plants. This method is perfect for you if you only have an insufficient supply of worm castings. You can use this top dressing for your garden and potted plants by simply spreading around half to one inch of the castings around every plant’s stem. Castings that are one-inch wide are often enough but to achieve more benefits, increase the band to around two or three inches. You should then water the plants after as a means of soaking the spread castings deeply.
  2. Liquid Fertilizer – You can also expect the worm castings you have created to work effectively as a liquid fertilizer. You can form this fertilizer by mixing one gallon of water with one cup of the castings. Let it rest there for at least one week. Once the 1-week period is up, you can start using the water produced by this procedure as fertilizer. It is also useful in the effective control of insects.
  3. Soil Conditioner – Another way to use worm castings is as a means to condition the soil. This means that even barren soil can be turned into a garden with the worm castings around. Just put one layer of the worm castings over barren soil. A thicker layer is a big advantage as it can make the plants grow. Spread then water the worm castings. Once done, you can begin planting on the soil.
  4. Seed Starter – Worm castings also work great when used in growing seeds. You can expect it to work effectively in protecting seedlings that are still thriving. Aside from that, the components of the worm castings can further increase the chance of the seedlings to survive. To use it that way, mix one portion of it with your starter mix. The perfect ratio is usually 1/3 worm castings, 1/3 vermiculite, and 1/3 coir. It is sufficient in powering up the seeds’ growth. Add the mixture to the provided containers then plant your preferred seeds immediately into them.
  5. Plant’s Base – This specific use of the worm castings works well if there is an existing sandy soil mixture. It makes it possible for this mixture to harbor sufficient amounts of nutrients that the plants can easily absorb. It is also a big help when the fruiting or flowering season arrives. You can use it that way by digging the soil slowly, allowing it to get into the plant’s base, forming around a narrow groove. Just ensure that you do so without causing damage to the soil. After that, put the castings within the furrow then cover it a bit with the soil. Once done, you can begin watering the plants.
  6. Effective Soil Preparation – You will also have an easier time preparing the soil with the aid of worm castings. You can use this effective fertilizer to turn your soil into a healthy one that supports the growth of plants. Preparing the soil using worm castings, however, require you to use a lot of them. You need to spread worm castings abundantly and widely. Make sure that that the spread is even, too. In most cases, you can use a high-quality dry spreader to perform this function, though this will depend on how big the area is. The perfect quantity is often 2-3 inches of worm castings that you have to collect similar to when you are plowing a land.

Apart from the mentioned users, worm castings also seem to work well when utilized as a tonic every time you water your plants. Moreover, it also serves as an effective foliar spray. Just put a handful of the castings inside a 1-gallon bucket then pour one to two cups of fish or seaweed fertilizer. Once done, you can start taking advantage of this solution as a foliar spray.


Worm castings are surely great additions to any garden. They serve as genuinely great fertilizers designed to improve the health and growth of your plants. One tip to remember when using the worm castings is to have them incorporated into your soil, instead of just spreading on top.

The reason is that the beneficial microbes present in the castings will have a higher chance of surviving and producing more benefits if you put them beneath the topmost part of the soil. That way, you can prevent them from getting excessively exposed to the sun that may cause them to dry out.

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