Pests in greenhouses come in various forms. In addition to insects, diseases, and weeds, a common type of pest that causes damage to seeds, seedlings, and overwintering stock plants is rodents, particularly mice, which is the focus of this article. Mice eating seeds in greenhouse is an age-long development but this article guides you on controlling them.
If you come across exposed, chewed, or missing seeds in your greenhouse trays, it’s likely a sign of mouse activity. Mice survive in greenhouses due to their favorable habitat. In a typical greenhouse, mice easily access abundant food, water, warmth, shelter, and protection from predators. Unfortunately, this also means that their populations can quickly multiply, making it tougher to control their presence.
Mice eating seeds in greenhouse
A white-footed mouse and the deer mouse are the prevailing rodent species you’d find in greenhouses. Both species belong to the Peromyscus genus and are sometimes mistaken for the house mouse, scientifically known as Mus musculus.
White-footed and deer mice have distinct physical characteristics, including the following:
- white feet
- white underside, and
- brown upper surface
- relatively large eyes and ears
- long tails
Deer mice and white-footed mice are predominantly active during the night—they are nocturnal creatures. Naturally adapted to outdoor environments, their diet mainly comprises seeds, berries, and nuts. Research has shown that they play a valuable role in consuming weed seeds in crop fields. However, in greenhouses, these critters tend to unearth and eat seeds as well as very small seedlings in pots and trays. That can sometimes be expensive damage.
How to stop mice eating seeds in greenhouse
There are many humane and also inhumane ways to control mice presence in your greenhouse. However, humane methods are often recommended to prevent exterminating non-target animals. That said, consider the following methods to stop mice eating seeds in greenhouse:
1. Create a greenhouse moat
Although mice can swim, they can also be deterred by a cold bath. Therefore, use this to your advantage to control mice in your greenhouse by positioning your pots of seedlings inside trays filled with water. This method also protects your seedlings against other potential pests like slugs and snails.
2. Cover your seedlings
Get seed trays that come with a tightly fitting clear plastic lid to prevent mice from potentially eating seeds in the greenhouse. The lids can create a mini greenhouse effect, ensuring the seeds remain slightly warmer and protected from drying out. Secondly, these plastic covers act as a physical barrier against mice. Fasten the lids to keep mice from coming into the seed trays from beneath.
When initiating the seed-starting process in your greenhouse, these covers will safeguard your trays. Place the covers over your trays to maintain ideal conditions for your seedlings, at least until they outgrow the covers and require removal. This practice also preserves the optimal environment for your seedlings’ growth and development.
3. Raise the seedlings above the ground level
You want to give mice a tougher challenge by raising the seedlings to form a barrier that discourages mice from reaching the plants. You can repurpose old shelving units as a solution. The shelves, typically constructed with pine slats, present an added challenge for mice. Not only would a mouse need to climb the height of the shelves to access your seedlings, but they would also have to navigate along the narrow wooden surfaces, which requires a precarious effort.
Experts have observed a significant difference in the exposure of seedlings to mouse nibbling based on the shelve placement. Those seedlings you position on higher shelves are often less targeted by a mouse compared to those situated on lower shelves.
4. Invest in ultrasonic deterrent devices
If you find yourself feeling frustrated about mice eating seeds in greenhouse, consider the ultrasonic rodent deterrents. These devices emit ultrasonic frequencies specifically designed to repel rodents and can serve as an additional measure to deter mice from your greenhouse. However, FTC challenged the claims that ultrasonic deterrent devices eliminate rodent infestations.¹
The sound emitted by these devices is high-pitched and beyond the audible range for humans, yet extremely uncomfortable for mice. The advantage is that it is an affordable and chemical-free alternative, even though there is no concrete evidence that it works. You might be interested in other ways to repel mice with noise.
5. Caulk up the holes
Mice don’t merely walk into your greenhouse to unearth seeds and devour seedlings; they gain entry from the outside. You can keep them from attacking your plants, by performing a comprehensive inspection to identify potential entry points. Inspect the walls and panels for any holes, and seal them to keep mice at bay. You should also make it a habit to keep the greenhouse door closed at all times.
Make sure to check the perimeter of your greenhouse, particularly the lower portion, for any holes or openings. On multiple occasions, mice have successfully burrowed under the walls and emerged inside the greenhouse, so fill up and seal these holes, as soon as possible.
6. Declutter and maintain a clean environment
Regular maintenance and good sanitation habits can greatly prevent mice eating seeds in greenhouse. That said, never store pet food or place garbage bins inside the greenhouse. Also, make it a habit to visit your greenhouse daily and put things in place to potentially deter mice.
You also want to remove debris such as dried leaves and fallen fruits. Maintain low grass and trim shrubs to prevent mice from seeking shelter beneath them. Outside the area, take down overgrown vegetation, which can serve as hiding spots for mice.
Even piles of firewood and stacks of abandoned furniture can provide opportunities for mice to dwell. Compost bins and trash cans should be built with sturdy materials with tightly sealed lids to prevent mice from breaking in. A clean greenhouse surrounding won’t necessarily keep mice away but they do not consider a clean and decluttered environment a safe zone.
7. Hire a pet guard
Pets such as dogs and cats can scare mice away from the greenhouse. Although not commonly considered a solution, it can be an effective method alongside other preventive techniques. A dog or a cat in your garden is a risky business for mice lingering in the area.
However, while it may seem like a reliable solution, you shouldn’t allow free-roaming animals inside the greenhouse due to the potential mess that may occur while chasing rodents. Moreover, your pet risks contracting diseases from caught mice.
Experts recommend not allowing your dog to roam freely in the garden due to the presence of outdoor succulents and cacti. Instead, place your Rottweiler in a cage a short distance from the greenhouse. Mice have a keen sense of smell² and can detect the presence of dogs nearby. This approach may not be as effective as allowing them to roam freely but mice will be deterred by the barking Rottweiler.
8. Get humane mouse traps
Consider mouse humane traps placed throughout your greenhouse to capture mice. Humane traps, such as mice bucket trap, captures and allows you to release mice unharmed, however, traditional mouse traps typically offer a quicker elimination and arguably a more humane option compared to poison. But never use glue traps unless you mean to be mean.
If you mouse traps, make sure to check them regularly. Humane traps should be checked daily while traditional traps will require regular emptying to prevent an unpleasant odor from permeating your greenhouse.
9. Consider poisoning as the last option
Not everyone may share the same opinion, but if you have exhausted all other alternatives and your sweetcorn and squash continue to suffer severe damage, it might be worth considering poison. But you risk exposing non-target animals including your pet to its harmful effects.
If you are determined to use poison, place them along the walls inside your greenhouse because mice prefer running along the sides of walls to crossing open ground. Also, understand that introducing such chemicals into a greenhouse where food crops are being cultivated may not be the most prudent decision.
Rodent poison does not provide instant results, and it may take several weeks before you notice a significant reduction in your rodent presence.
Why you have mice in your greenhouse
Greenhouses offer mice an ideal refuge and nesting spot due to the warmth they provide and the abundant array of food sources available.
1. Abundant food sources
The enticing scent of food sources like fruit-bearing plants, vegetables, and compost bins in the greenhouse attracts mice. Additionally, bird seeds from feeders can also be highly effective in attracting rats. “Humans have approximately 350 different odorant receptors, whereas mice have approximately 1,000,” according to McGraw Hill Medical.³
The moment they catch a whiff of any enticing scent—food or foul-smelling garbage— it lures them in. When compost bins are left uncovered, they create a hospitable environment for mice, providing them with an opportunity to stay and scavenge for food.
2. Unfixed water sources
Mice are drawn to sources of stagnant water such as leaky pipes, water buckets, and puddles. They are also known to target ponds and swamps in the vicinity as reliable water sources. Freshwater sources are highly appealing to rats, as they have a daily requirement for water.
3. Stockpiles of debris and wood
Areas with piles of wood, debris, cardboard boxes, and dense shrubs are a hotspot for mice. Trash serve as a hiding place, shielding them from potential predators. For warmth and protection from harsh weather conditions, particularly during winter, mice hide in these inconspicuous locations and even prefer to establish habitats beneath stationary objects for an ideal refuge.
Mice damage in the greenhouse
Once mice infest your greenhouse, their impact can be highly destructive. In addition to the potential transmission of diseases like Leptospirosis, they can cause significant damage within the greenhouse. This includes biting seedlings and fruits, gnawing on electric wires, pipelines, and wooden fixtures, as well as displacing plants by knocking them to the ground during their movements.
Apart from the plants, mice can also damage pipelines and electric wires. You’d notice scratches on the fence and shed doors, that’s because mice gnaw on these non-food objects and on hard materials to maintain the length and sharpness of their front teeth.
These mischievous critters can also cause significant harm by transmitting diseases such as leptospirosis. Inhaling dust contaminated with mice droppings and urine can lead to various serious health issues, including Hantavirus and Hemorrhagic fever.
What mice eat the most in the greenhouse
Mice exhibit omnivorous behavior, which means they will consume any food that appeals to them, whether it is of animal or plant origin. Mice have a particular fondness for the following foods:
Mice eat the greenhouse seeds as well. Apart from mice eating seeds in greenhouse, they also go after bulbs, ripe fruits, compost material, and even pet food.
Mice also nibble on certain plants, including amaryllis. Interestingly, the presence of amaryllis can also act as a deterrent.
Mice have diverse dietary preferences, including animal fat, carbohydrates, and protein. Therefore, compost bins containing food scraps such as seeds, meat, eggs, and grains can be enticing to mice.
They also consider pet foods to be a prime source of nutrition. Feeding dogs, cats, chickens, birds, or rabbits inside the greenhouse inadvertently provide mice with a food source. Make sure you clean up feeding areas and get rid of animal waste, including pigeon feces because mice are coprophagic rodents and will feed on them too.
Read also: how to keep mice off the table