Benefits of Worm Castings

If you’re looking for a high-quality natural fertilizer, there’s not a better option out there than the castings of worms. They are byproducts of vermicomposting, which is the composting method that uses worms to decompose food waste. 

They are easy to harvest, too. All you need is to start vermicomposting is a worm compost with a worm bin, soil, organic matter, worms, and time. You can collect castings from your compost regularly and apply them to your soil. 

Worm poop, also known as castings, is collected from worm farming. They are super high in nutrients like nitrogen, potassium, magnesium, and phosphorous. Their high nutrient content makes them perfect for natural fertilization. The benefits of worm casting are significant to both the soil itself and your plants that grow in it. 

Benefits of Worm Castings for the Soil

The health of the soil and organic matter itself often gets overlooked, but it’s just as important as the health of your plants. The wonderful thing about castings is that they aren’t only great for your plants; they also benefit the overall composition of your soil when you apply them. 

Adding castings to your organic material, garden, or potting soil increases the water retention capabilities of the soil. Better water retention means that the soil stays aerated for longer periods, which helps plants absorb the nutrients they need that would normally get washed away from excess watering. 

Earthworm castings have a very high nutrient and mineral concentration. The nutrient levels found in vermicomposting are higher than those of compost tea, worm tea, and regular bulk compost. 

The castings contain the elements iron, sulfur, magnesium, potassium, calcium, nitrogen, phosphorous, and more. All of these nutrients combined make for a high-quality soil composition that will ensure your plants grow healthy and strong. 

Castings act as a slow-release fertilizer, meaning that even the nutrients seep into the soil over time rather than immediately. This is significant because it not only benefits your soil upon immediate application, but it continues to benefit your soil year after year. 

Studies have found that the castings of earthworms contain rich microbial organisms that can even help fight off soil-borne pathogens and repel pests like rodents and insects. 

Benefits to Plants 

Castings are a plant superfood that provides nutrients and minerals that benefit plant growth and quality. Castings stay in the topsoil and provide continuous nourishment to plants, unlike chemical fertilizers that wash out after a single use. 

Earthworm castings are rich in several nutrients that plants need to thrive. Studies have shown that castings cause a direct improvement in a plant’s bloom size, color, quality, and quantity. 

A study performed by Cornell University showed that castings protected plants from common pests and diseases as well. Castings reduce a plant’s likelihood of developing root rot or wilt. They also reduced plant’s likelihood of being overrun by pests like aphids and mites. 

Castings contain a chemical called humic acid, which has various benefits for plant growth. Humic acid increases the plant’s ability to absorb nutrients and makes the plant more tolerant to drought conditions. 

Castings also help with seed production and germination. Once a seed is in the ground, the nutrients present in the organic matter of castings encourage the seed to develop healthy roots and grow strong. 

Benefits to Garden

Castings work the best when they have been incorporated into your garden’s soil before planting. Applying castings is as simple as applying mulch or fertilizer to your garden. 

Castings contain highly concentrated nutrients, so you don’t need a ton to fertilize your garden. Applying ¼ cup or ½ cup per 100 square feet will work just fine. After incorporating the castings into the soil, your garden will be ready to reap the benefits. 

The castings of worms provide a slow-release, water-soluble fertilizer with an NPK ratio of 5-5-3. The castings provide your garden with the best soil possible to help your plants grow. 

Frequently Asked Questions

Now that we’ve covered the basics of castings and their benefits, you may have some questions. Don’t worry because we have answers. Below are some of the most frequently asked questions about using castings and what their benefits are. 

Are Worm Castings Good for All Plants? 

Castings are safe and easy to use on all plants. Castings simply act as a nutrient-rich fertilizer for your plants. 

These castings have no negative effects or reactions in the soil. Castings are chemical-free and provide slow-releasing fertilization for plants both present-day and for years to come. 

Can You Use Too Much Worm Castings? 

While you only need as little as ¼ cup per 100 square feet, it’s very difficult to add too many castings to your soil. 

Unlike most chemical fertilizers, putting too many castings or too much worm tea onto your plants will have little to no negative effects. 

Applying an excessive amount of castings can overload your soil’s nutrient content, but this is very hard to do. Over time, you can use fewer castings since the effects of the fertilizer linger in the soil. 

How Often Should I Use Worm Castings? 

It’s best to re-apply castings every few months to get the best results. You only need to mix the castings into the soil at the beginning of each planting season or before repotting your plants. 

You can apply small amounts of castings once a month around the base of your plants to refresh the nutrient content. 

Are Worm Castings Better than Compost? 

Castings have a higher level of microorganisms and more concentrated nutrients than compost does. Compost, however, contains higher levels of major nutrients than castings. You can use both castings and compost in your garden to help it grow as well as possible.

Are Worm Castings Considered Fertilizer? 

Castings are a slow-release fertilizer. They provide high levels of nutrients that help with seed germination as well as plant growth. 

Can You Put Worm Castings on Top of Soil? 

It’s best to incorporate castings into your soil at the beginning of each planting period or before repotting. After you’ve planted your plants, you can add castings to the top of the soil surrounding the plants as a refresher to help boost the nutrient level of the soil. 

Happy Gardening

Castings are a great addition to any soil in any garden. They provide essential nutrients and microorganisms to help your plants grow to be as strong and fruitful as possible. 

But don’t just take our word for it. Start your worm farm and collect your worm manure, or purchase pre-packaged castings, and find out the benefits for yourself.


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