Greenhouses can sometimes attract rats, mice and other rodents, but fortunately there are a whole host of ways you can keep vermin at bay.
Why Do Greenhouses Attract Rodents?
Like us, rats and mice like a warm cosy and safe environment to live in. They also like a ready supply of food. In many ways a greenhouse is the perfect opportunity for rats and mice to find these conditions.
Greenhouses by their very nature tend to be warmer than the outside temperature, making them appealing homes in the winter months. They can also house all manner of tasty morsels for rodents to eat – not just fruits and vegetables, but even fresh green shoots and seedlings can offer appeal.
Of course, how likely it is that rats and mice will be attracted to your greenhouse can be affected by a range of factors, which we’ll discuss below.
One of the most important is simply how many rodents there are in your local area; those living in cities or near to farming areas are likely to find there are far more rodents about to begin with, as opposed to those of us living in suburbia.
When Do Greenhouses Attract Rats and Mice?
Greenhouses are most likely to attract rats and mice in winter and spring. In winter they’re warm, dry and cosy – a perfect place to build a nest or dig a little burrow.
In spring they’re not only warmer than the outside temperature, but are often also bursting with fresh food for them to eat.
Speaking from my own personal experience, juicy fresh pea shoots and sweet corn seedlings seem to be particularly appetizing meals for acrobatic rodents on the hunt for a meal.
Rodent problems seem to be less common in the summer months, where a typical glass or plastic greenhouse can get far too warm for rats and mice. The fact that you’re in and out all the time, causing disturbance, can also make them less appealing homes.
What Plants Attract Rats & Mice?
Rats and mice tend to be drawn to two things; overgrown plants where they can hide away from predators and feel safe, and fresh food that they can eat.
There is no exhaustive list of plants that will attract rodents, but the following broad list should give you some idea of what to watch:
Dense foliage – Can give rats and mice a cosy place to build a nest. Rodents tend to dislike open spaces, where they feel unsafe, so consider trimming unruly plants before winter sets in.
Food plants – Anything from fresh green shoots, to seeds can easily be dug up, to ripening fruit, will all be of interest to rodents. Try to keep these out of harm’s way wherever possible, for example placing seed trays up off the ground on greenhouse racking where they are harder to reach.
How to Deter Rats & Mice from Your Greenhouse
While rats and mice can become a problem in your greenhouse, luckily there are a whole host of ways to deter them. If you’re being plagued by rodents then here are some crucial factors to consider:
Fill Any Gaps in Your Greenhouse
For rats and mice to cause problems in your greenhouse they first need to get inside. Spend some time carefully examining your greenhouse to see if there are any areas where rodents may be able to gain access. Examples might be loose or missing glass panels, doors that don’t fit snugly, or tiny gaps in the corners where the greenhouse walls meet.
Remember that mice, in particular, need only the tiniest of gaps to access your greenhouse, so aim to block any possible entry routes that you find. If necessary, silicon glue can be used to seal tiny gaps.
Lay Down Solid Flooring
Another route of entry for rats and mice is from underground. Most rodents are more than capable of burrowing under the walls of your greenhouse, and popping up inside. A solid floor can help to prevent this.
Rather than a plain-earth floor as many people use, instead consider adding a good layer of hardcore to the floor of your greenhouse. Tamp it down firmly to make an impermeable barrier. Even better, consider laying paving slabs on top of this.
A paved greenhouse floor doesn’t just help to keep out burrowing rodents. It can also help to hold the sun’s heat in winter, keeping your greenhouse warmer, and can help to keep shoes and boots dry and mud-free after heavy rain.
Give Your Greenhouse a Clean
Like garden sheds, greenhouses can offer cosy places to build a nest. Stacks of plant pots, old compost bags and the like can all provide cover for rodents.
It is therefore a good idea to routinely pull everything out of your greenhouse, give it a thorough clean with some greenhouse detergent, and put everything back once it’s dry. A clean and tidy greenhouse will be far less appealing to rats and mice.
Also, be aware that rats and mice can naturally be attracted to the smell of other rodents. A thorough and regular cleaning regime can help to eliminate any such scents, further keeping unwanted pests at bay.
Prune Back Unruly Plants
Just like clutter can provide hiding places for rats and mice, so too can overgrown plants. I’ve watched rats clambering along an ivy-clad wall, for example, safe in the knowledge that they can quickly disappear from view at a moment’s notice.
So before winter sets in, carefully consider if any of your greenhouse plants could benefit from a prune. Once pruned, dispose of the cuttings safely in a compost or garden waste bin.
Raise Seedlings Off the Ground
One area where I have really struggled over the years is with mice nibbling my spring seedlings.
There is little more frustrating than investing time, money and love into getting your seeds going in spring, only to enter the greenhouse one morning and find them all destroyed.
One of the most effective solutions I have found is to place seed trays off the ground, on tables or greenhouse staging, where rats and mice will find them much harder to reach.
An alternative, of course, is to plant seeds in your house. Place them on a sunny windowsill where they can benefit from the warmth and sunlight. Only once they become established – and therefore less appealing to mice – can they be grown on in your greenhouse.
Spend Time in Your Greenhouse
Rodents like peace and quiet. This is another reason why rats and mice are more likely to stay at “Hotel Greenhouse” in the winter months, when they’re far less likely to be disturbed.
Spending time in your greenhouse can cause disturbance, and make it a less-appealing home for some vermin. So don’t just ignore your greenhouse all winter long. Instead, invest a little time each weekend, even in the worst winter, to care for your greenhouse.
Doing so also represents a perfect opportunity to check for any signs of rodents, such as nibbled plants, freshly-dug burrows or the unmistakable scent of mouse urine. In this way, even if you are unlucky enough to have rats or mice taking up residence in your greenhouse, you should spot – and therefore be able to fix – the problem as soon as possible.
Consider Humane Traps
As a final resort, when all your other efforts to deter rats and mice from your greenhouse have failed, it may be time to consider humane traps. They’re available cheaply from most gardening centers and online at places like Amazon.
I recommend buying a number of traps if you can afford them. Add the bait (I find peanut butter works well) then place them against the inner walls of your greenhouse. Rats and mice tend to “skirt” round the walls to feel safe, so placing the traps here maximises your chances of success.
It goes without saying that if you decide to opt for humane traps then be sure to check the traps daily. Any rodents caught can then be released some distance from your greenhouse.