How to Keep Rats out of Your Compost

With cold days approaching, the need for warmth and plenty of food, where would you choose to shelter? Well, if you were a rat, it could well be in a compost heap – somewhere with plenty of fresh kitchen scraps to feast on and a nice bit of heat from the decomposing material.

This is certainly what one rat thought of my heap a few years ago. I raised the lid on a nearly full bin and came eyeball to eyeball with a feasting rodent. Was there ever a larger rat with longer teeth? Probably, but shock magnified the scene and I only had a glimpse as my shriek rent the air and, with lightning speed, it whipped down a hole to the nether regions of the bin.

It was most definitely time to get involved in some rat-proofing. If you find the idea of coming face to face with a rodent as repellent as I did, I’m glad to say that a few simple measures ensured that I haven’t ever had the same experience again.

Five Ways to Rat-Proof Your Compost Bin

1. Use a solid-sided bin. If you have a wooden, open-slatted bin then it’s best to use it only for garden waste. Vegetable peelings and other kitchen waste (rats are, apparently, particularly partial to potato peelings) should go in a closed bin, with solid sides and a lid. Some of the commercial plastic varieties come with a rat-proof base, but if yours doesn’t then place it on wire mesh. Rats can squeeze through gaps of 15 mm (just over half an inch), so the holes in the mesh need to be smaller than this. It also needs to be heavy-duty. Chicken wire isn’t thick enough as rodent teeth are sharp! I use a galvanised, 13mm x 13 mm (0.5 x 0.5 inches) light welded mesh.
2. Ensure the bin is set squarely so that there is no gap between the sides and the lid. This makes it harder for a rat to gain an easy purchase. Rats love nothing more than finding an edge to nibble on. I made the mistake of not setting the bin squarely, and teeth marks made it very clear what had made the hole I found.
3. Rats are secretive souls. They prefer to keep to the edges of things and haunt passages like those made between a fence and a closely positioned shed. Situate your compost heap as much in the open as possible, away from likely rat-runs along over-grown fence-lines and the sides of buildings, so that they are discouraged by a lack of cover.
4. Rats don’t like disturbance. Putting the bin somewhere you pass by often and giving it a good rat-a-tat on the side with a stick every time will discourage them from taking up residence.
5. Don’t add cooked food, especially meat and fish, or anything strong-smelling like cheese and fats to the bin. I also found that egg shells were a particular favourite, to the extent that they started calling at it for a take-away.

Take Stock of Your Garden

Once your bin is sorted, have an objective look round your garden from a rat’s point of view. The current enthusiasm for wildlife gardening isn’t selective when it comes to the wildlife it attracts, so rodents can be the penalty we pay for long grass and wildflower meadows. It would be a shame to get rid of these if you like them, but it’s better not to have the compost heap in the middle.

Bird feeders also need looking at. Birds are nothing if not messy eaters and lots of grain tends to fall to the ground beneath which is a major attraction for rats. Consider setting a large paving slab below the feeder so that it’s easier to brush up fallen seed.

Once you’ve carried out a few simple measures, you should find that rats move on to find easier lodgings. If you do find the rats in your area are particularly persistent, then it could be the moment to consider a well-built compost tumbler.

By Helen Gazeley