Are Worm Castings Good Fertilizer?

Are worm castings good fertilizer? Worm castings are some of the best organic fertilizer available to man! This type of fertilizer provide beneficial bacteria and enzymes to the soil which gives plants a very healthy start. In short, worm castings help the plants take the much-needed nutrients from the soil much easier than without.

What Are Worm Castings?

Well, worm castings is actually worm poop, the little worms eat waste products such as leafy greens banana peals and much more. Worm castings is actually very tiny football shaped turds and is also referred to as vermicompost or worm poop. The closest thing I can think to relate worm casting to plants is probiotics to humans. It aids in digestion of nutrients. Most plants that introduced to worm casting have a healthy start and produce much more during their life cycle.

Difference Between Worm Castings and Vermicompost

While worm castings are pure worm poop, vermicompost may have bits and pieces of bedding material and even some left over food particles. Making sure your worms are getting the correct food is very necessary as you do not want harmful bacteria being placed in your garden or plants. Worm castings can hold 2 – 3 times their own weight in water whereas if coconut coir used in bedding mix can hold up to 10 times the weight in water. Bedding material is very important part of the worm castings or vermicompost procedures.

NPK Values in Worm Castings

If you was to check the NPK rating in worm castings you may get a surprise you wouldn’t expect. A bag of worm castings is normally rated at 1-0-0 unlike most store bought fertilizers. The nutrients you get from the worm castings is directly related to what they had to eat. They love organic waste, but do eat bedding materials or any other organic material they might happen to find. The mucus has a high rate of microbial organisms that are very good for the soil and plants.

Commercial Worm Farms

Some farms main purpose is to produce worms for fisherman or for animal feed. In this case the worm castings or vermicompost is a secondary product or better called a byproduct. More and more you will see commercial worm farms choosing vermicompost as the primary product and selling worms to start up farmers, bait, and feed purposes. Both style farms help in the reduction of organic waste which is a great plus for planet Earth. Worm farms can use long windrows or beds. In warmer climates the windrows are used as they can farm them year round. In colder climates the bed system seems to work best as often they are in greenhouses or other heated building so the worms can thrive year round. Usually the vermicompost or worm castings are sifted to remove worms or other debris to get a clean product. In most cases if the worm cocoons cannot get sifted they leave the castings or vermicompost set in a bed a number of days to allow the cocoons to hatch. they are sifted again for baby worms and bagged and sent out as finished product.

Benefits Of Using Worm Castings Or Vermicompost

Worm Castings Do Not Over Fertilize Plants

Unlike most other organic fertilizers or chemically induced fertilizer will not burn up your plants. The digestion process of the worms makes the compost the perfect amount for plants.


Worm Castings and Vermicompost is Rich in Micronutrients

Even that we have told you the NPK values are really low, there are also many more minerals left to aid they plants. Last I saw there is over 60 different minerals in worm castings. Some of the more dominate ones are manganese, iron, calcium, and copper.

Adds Pest Resistance

Most of your garden variety pest such as whiteflies, spider mites and aphids is among the most known to avoid worm castings. I have seen worm tea sprayed as a foliage or worm castings themselves used as mulching on top of the beds. This way when the garden or plants get watered the nutrients from the worm castings go down to the root structure so the plant continues receiving the benefits.


Higher Yield is The Best Benefit

The enzymes (good microbial populations) in the worm castings allow the plants to absorb nutrients in the soil easier and faster which in turn allows the plant to produce larger and even more yield than they can without this organic soil. Are Worm castings good fertilizer? Oh yea, the best!

Can Better Handle Dry Spells

As mentioned earlier in this article, depending on the mixture of the vermicompost, the water retention can be up to 10 times its own weight in water. This of course keeps the soil moister which also aids in the plants being able to absorb the good nutrients. Less problematic for the dryer times we all know as growers comes along.

Helps Keep Diseases at bay

Worm castings naturally provide disease protection as most fungal-based diseases do not thrive in worm castings. The good bacteria and microbial life can kill off dangerous diseases. Vermicompost also aids in killing off and preventing bacterial diseases as well.

Soil is Improved

Because of all the organic material in the vermicompost the soil increases every year, When chemical based fertilizers are used the makeup of the soil gets stripped every year and must always have more added on a yearly bases. Organic fertilizer actually builds the soil to be better and better each year.



Some vermicompost or worm castings will contain worm cocoons which means good things for the plants or gardens. Worms will hatch and help the plants by providing more and more castings and they also remove heavy metals that may be in the soil and breakdown and organic matter they may find. They also make little tunnels in the soil which allows oxygen and water to get to the plant roots. That alone will yield better results.

You will still need other fertilizer

As we brought to your attention earlier, the NPK values are really low in worm castings to adding other nutrients is a must. Starting with a good soil base may supply the plants with plenty, but some additional nutrients to aid in root growth and other areas may need to be added.


As good as worm castings are, the cost of using on a large scale may be cost prohibited. Vermicompost or worm castings can be very expensive compared to other sources of nutrients. At the end of the day if you’re growing organic, your customers will value the goodness you produce without the aid of chemicals and the market has proven a 40% increase in retail products, although not wide scale, are accepted.

I hope this answered your question are worm castings a good fertilizer. I invite you below to leave a comment or questions concerning worm castings or vermicompost and I will answer them as quick as possible.

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