Buying Worm Castings – What to Look For


If you’re in the market for worm castings, that is fantastic news! You’ve discovered the greatest plant food/soil supplement that the world has to offer. It’s great for any type of plant, it can be used in organic growing methods, and it is extremely potent.

Although we’re really glad that you’ve narrowed your search down to worm castings, there are a few things that you’ll want to take into consideration before you make a purchase. Here are some things to look for when buying worm castings.

What Type of Worms Were Used?

A lot of products out there are labelled as “worm castings” and in most cases that is factually correct. However, there are several different types of worms that can make castings, and they’re not all the same.

For example, one of the most common types of worm castings on the market is made by “red wiggler” worms. These are little red worms that are primarily used in composting. If you get one of those worm composting bins and throw table scraps, etc in it, there’s a good chance you’re using red wigglers to do that composting. They are perfect for that.

However, the castings they make using that method are on the small side and have a lower microbial count. The nutrients and minerals in the castings are also on the low end and generally differ from one batch to the next. The nutrients they put out directly correlate to the food source that is being given to them.

By comparison, some worm casting products are made with earthworms. These are large, muscular, brownish colored worms that have the capability to burrow deep into the soil in the wild. These types of worms generally make a larger casting that is high in nutrients, minerals and microbial life. They aren’t generally composting, but they’re eating soil and turning it into “super soil”.

For example, Simple Grow uses African Nightcrawlers. These are a large, aggressive worm that can eat up to 1.5 times its own body weight in dirt every day.

What and How Were the Worms Fed?

The other big factor in the quality of the castings is the food source that the worms are given and how they are fed. When purchasing castings, you should make sure that the castings come from a controlled food source.

Many times, with composting worms, they are given whatever the producer can get their hands on: table scraps, yard waste, leaves, and animal manure. This makes it very difficult to create a consistent product with the same nutrient levels in it. With a controlled diet of rich, black dirt and grain, worms are able to produce a casting that is absolutely perfect for plants.

At Simple Grow, we use African nightcrawlers and keep them in a controlled environment with a consistent diet. This creates amazing worm castings in every batch. That means you can rest assured when you order from Simple Grow, you’re getting the highest quality, pure earthworm castings that you can find anywhere.