If you’re looking into what soil supplement to use for your plants, you might be considering both compost and worm castings. Which one is better? Which one should you use in your garden or planters?
The short answer is...worm castings are a superior product. However, it’s not always that simple. Depending on the application and situation, compost definitely has its place to. Here are a few things to consider.
Benefit to Plants
When comparing the two, worm castings have much superior benefits to helping your plants. The microbes in the castings are perfect for boosting plant growth and creating healthier plants. They also help protect plants from disease and pests. By the way, if you aren't sure where else you can use castings, find out here.
Additionally, castings provide aeration because of the way that they can’t be packed down like regular soil. This means they help oxygen flow to the roots of the plant, boosting growth even further.
Worm castings are also the ideal moisture regulator for plants. They’ll absorb water, hang onto it, and then release it as the plant needs some. By comparison, compost doesn’t really do any of these things.
There can be some nutrients and in some cases, small amounts of helpful microbes. However, those are usually not at the highest levels and are inconsistent.
Growing Medium vs. Soil Supplement
Although you’re comparing worm castings and compost, they typically aren’t used in the same exact applications. Compost is typically purchased as the base of a growing medium. Worm castings are often used as a soil supplement and not necessarily the base.
For example, in a planter, you might use 60-90% compost. If you were also mixing worm castings in, you might use 10-40%. Compost usually has better nutritional value than standard soil. So using it as a base and then supplementing it with things like worm castings, perlite, and azomite can help create the ideal growing environment.
With that being said, some people do grow with worm castings as a base. It’s not typical because the cost of worm castings per pound is higher than something like compost. As far as planting in castings, it can be done and the chances are your plants will do great.
However, for economic reasons, most people start out with soil or compost and then supplement that with castings. Using somewhere around 20-30% castings is a great ratio.
Pesticides and Inconsistent Contents
When comparing the two, you have to consider how each material is produced. Compost is made by taking organic materials and leaving them in a pile to compost for an extended period of time.
Things like leaves, yard waste, table scraps, manure, sticks and leaves are thrown together. The mixture breaks down and you’re left with a combination of organic material. That can provide for some nutrient rich growing medium to work with. However, it can also lead to some issues.
What happens when you put grass clippings with pesticide on them into the mixture. Do you think the pesticide disappears? No it doesn’t. It’s now in the compost. Any other chemicals that are on the individual materials in the compost will now also be in the compost.
Another factor to think about is that each batch of compost is different. You never put the exact same materials in the exact same proportions into the compost pile. It’s random and difficult to predict exactly how it will turn out.
One batch might be high in nitrogen and low in potassium. The other might be high in potassium and have virtually no nitrogen. This makes it difficult to count on exclusively when you’re planting.
By comparison, pure earthworm castings are very easy to count on. You know the N-P-K ratio and all of the trace minerals in the product. You know you’re getting high levels of beneficial microbes. If you buy a high-quality earthworm casting like Simple Grow, you know that it’s approved for organic use and free from pesticides and other chemicals.
Deciding What to Use
If you’re debating what to use on your garden or planters, worm castings definitely should be in the mix. In many cases, using a combination of compost and worm castings is a good solution.
For example, you could use 60-70% compost and the rest worm castings. This will allow you to get the benefits of worm castings for your plants, while also keeping the cost down overall. Compost is generally inexpensive and readily available. So using it for the majority of your base typically works out well.
Supplementing With Tea
When using compost and worm castings, you may also want to consider supplementing the mixture with worm castings tea. This is a liquid mixture of worm castings that you can spray onto the soil and plants. This will help get the microbes of the worm castings spread even further into the soil mixture.
Regardless of which solution you choose, be sure to use high quality worm castings from Simple Grow. You’ll get consistent results and your plants will love it.