How Many Composting Worms Do You Need?

by Sam Richards | Last Updated: August 24, 2020

Worm composting has long been a popular method for providing soil the with the nutrients necessary for the health of plants. Through their castings, worms excrete organic matter that will fortify the ground and provide the valuable amendments that will help plants to thrive.

While many things will be influential in the success of vermicomposting, one of the most important would be the worms you will use. With this, many of you are most probably curious – how many worms do I need? There’s no easy way to answer this question as this will depend on several variables. Read on and learn from some of the insights we’ll be sharing in this short guide.

How Many Composting Worms Do I Need?

It depends – that is perhaps the best way to answer the question regarding the composting worms that you will need. Generally, two main factors will affect our answer to this question:

Once you know the two things mentioned above, it will now be easier for you to determine the amount of the composting worms that will be necessary for your bin. Below, we’ll take a closer look at these things.

Based on the Size of Your Bin

One of the best things to do is to start with the size of your bin. It is one of the easiest indicators of how many worms will be needed for composting. One good rule of thumb to follow is to use one pound of worms for every square foot in your composting bin. For instance, if you have two square feet bin, then you will need two pounds of worms.

However, two main things should be noted with the assumption above:

Based on the Food Waste You Produce

Aside from the size of the bin, another important consideration would be the food waste that you are producing at home. The more food scraps you have, the more worms there should be in your composting bin.

It is difficult to estimate the food scraps that you are making in one week. The best thing that you can do is to collect all the scraps and put them in a plastic bag. Weigh the food scraps. In a one to two-person home, you will have an average of four pounds in a week. For larger households, the food scraps can be eight to ten pounds in a week.

Once you know the amount of food waste that you are generating in the household, you can identify how many worms you will need to have in your composting bin. Here are some of the most important things to note.

How Many Worms are in One Pound?

In the case of most sellers, you will see that they are selling worms by the pound. You won’t have the chance to count how many worms are in a pound. Even if you have the opportunity, you will most likely not go through the hassle of doing so. Below are some of the most important things to keep in mind:

Can You Have Too Many Worms?

This is another question that raises the curiosity of many beginners in worm composting. It can be bad for your plants and worms themselves.

What Size of Bin is Needed?

Aside from the number of worms, the right size of the composting bin is also a crucial consideration. Here are some of the things to keep in mind:

How Many Composting Worms Should You Start With?

If you are a beginner, it is best to start with 250 to 500 worms in a small bin. Start small and grow your worms before going full-blown. When you are starting, you still have a lot of things to learn, and hence, you should be more cautious.

You should not buy thousands of worms, especially when you are on a budget. To save money, consider growing your worms. Start with a bag that contains 500 worms. Feed them based o their nutritional requirements, and eventually, they will reproduce. This way, you will have more worms out of the original number you have. The best thing is that you won’t need to buy more worms!

Picking the Right Bin

Much has been said about how many worms are needed in a compost. However, one more thing that you should know is the type of bin to use. Below are some pointers when it comes to bin selection:

Avoid Overfeeding Your Worms

Now that we have talked about how many worms you need in your compost, let’s talk about how you can feed them. They will eat fruits and vegetables, as well as paper, eggshells, and coffee grounds. Do not give them anything spicy. You should also avoid meat and processed food. The most important is that you do not overfeed the worms. Otherwise, here are some things that can happen.


At this point, we hope that we have already answered your question about how many worms are needed in a compost. In short, this will depend on two things – the size of the bin and the amount of food waste that you are making at home.

On average, you will need about one pound of worms for every square foot of space in your bin. More so, based on your food scraps, take note that worms can eat half of their body weight. So, if you have two square feet of bin, you will need two pounds of worms. More so, if you have two pounds of waste, then you will need four pounds of worms.