For the past few months, I’ve been exploring creative worm farm ideas, both above ground, and inground. There are some great manufactured worm bins available and a number of DIY projects as well. But one concern I’ve had was the potential of attracting rats. I dug into this and learned quite a bit. Here’s the bottom line:
Do worm farms attract rats? Worm farms generally only attract rats when 1) too much food is placed in the bin at one time, or 2) the wrong types of waste are added. If food scraps are added faster than the worms can break it down, the bin can attract rodents and vermin. Adding meat and dairy items will also attract them.
Controlling the amount of kitchen waste added and using the right food source is the single most effective strategy for preventing rats from being attracted to your worm farm.
Do Rats Eat Worms?
Rats are omnivores and opportunistic feeders. They will eat just about anything that is available and that does include worms. They won’t necessarily come looking for your worms as a food source. It’s usually the odor of rotting food that attracts them, especially rotting meats and soured dairy, but there are few items that aren’t on a rodent’s menu when it’s available.
Rats are notorious for getting into trash bins that are kept outside which makes the idea of an outdoor worm farm seem somewhat counterproductive. In fact, best practice is to keep any food-containing items that are outside covered (source).
But it is unlikely that rats are going to seek out your worm bin specifically for the worms. The smells of decomposing food are what will draw them in so let’s focus on that.
Keeping Rats Out Of A Worm Bin
The first key to keeping rats out of your worm farm is to control the amount of food placed in the bin at a time. A common thought process is that you simply continue piling your kitchen waste into the bin and eventually the worm population will grow to meet the food supply. There’s truth in this logic to a point but if you are piling excessive amounts of scraps in your bin it will give the excess food more time to rot and smell.
Start off slow and monitor the bin as you add small amounts of food. Let the demand dictate the supply in the beginning. Once your worm farm is firmly established and thriving, you can begin increasing the food supply gradually.
The second key is to only use only non-animal organic material. These are generally frowned upon as compost ingredients anyway but when it comes to preventing rodents, it’s critical. They are attracted by odors and meat and dairy waste give off a pungent odor as they decompose.
Bonus Tip: It’s good practice to blanket the kitchen waste with a nice layer of dried, brown material like dead leaves. This will help to reduce odors (source).
Covering Worm Farms To Prevent Rats
Addressing odors is your frontline defense but you can further reduce rodents and vermin by covering your worm bin. Depending on your setup, you have a lot of options.
Galvanized hardware cloth (link to Amazon) is a great choice if you have a large area to cover. It’s not cheap but it’s made to withstand the weather and to keep critters out. You will want one with a small 1/4″ mesh (smaller holes). They make these with larger spacing but those are more appropriate when just trying to keep larger critters out.
Solid covers can be used as well so long as they allow for air. A lot of people build worm farms in heavy-duty storage containers that have locking lids like this one on Amazon. These can work great, just make sure that you drill plenty of small holes through the lid.
You can also go with the cheaper storage containers that have “snap-on” type lids. Just put a large rock or something on it to keep the critters out.
It’s also important to remember that you would need to drill holes in the bottom of whatever storage bin you use to allow the liquid to seep out. If your bin is outside, the liquid can simply seep into the ground. The cheaper snap-on lid style storage bins are better used when creating an indoor worm farm because you can easily stack them to allow the liquid from the top container to seep into the bottom one.
The point is, you can further reduce the risk of rats getting into your worm farm by creating a physical barrier. Just be sure that you allow for plenty of air to get into the bin.
Worm farms should not attract rats so long as you are not overfeeding or using animal products in your bin. The strategies outlined in this article are simple and practical approaches that you can take to both reduce the attraction and deter the entry of rats into your worm farm.
Vermicomposting is an excellent method of reducing waste and making use of kitchen scraps and other organic material. Just make sure that you follow these guidelines to prevent unwanted guests from feasting in your worm farm.