CCGA Guide to Rats in Community Gardens

Download a PDF of the guide.

There is a concern among some people in Chicago that growing a garden, especially a food garden, will attract rats. Before you jump to that conclusion, please consider the following:

Every living Creature requires three things to survive: Food, Water and Shelter. Removing or altering anyone of these three things will negatively impact a creature’s ability to survive and they will leave to find them somewhere else.

About Chicago’s Rats

The common brown rat (Rattus norvegicus, also called the Norway rat or sewer rat) is a prolific wildlife species globally, especially in urban settings. They are found in cities because they thrive in the same places that humans live. 

Where Rats Live

“City rats” thrive in environments where uncontained garbage (food) and clutter (shelter) are located. They are as equally at home in dry, dusty environments as they are in dank, wet surroundings. They are drawn to structures with entry holes and broken walls such as abandoned and derelict buildings. When a neighborhood experiences increased demolition and construction, rats become displaced and will seek a new environment. They can build their nests in crevices along the outside walls of homes and buildings, burrow into soil, and under dense clumps of vegetation and debris. They may also construct nests beneath the edges of sidewalks or patios. They live in almost complete darkness, rarely emerging in daylight. 

The presence of rats can be detected by droppings or evidence of fresh gnawing, though there are many other wild animals in the city that leave droppings, tracks and evidence of gnawing. Tracks can be seen in mud and on dusty surfaces. Runways and burrows may be found next to buildings, along fences, in soil, under raised beds in community gardens and under low vegetation and debris.

What Rats Eat

Rats live off of whatever they can find that is edible. A typical city rat can feast on garbage that is easily accessible when the garbage cans in our alleys are often left open and overflowing. They are the original “junk food junkies” – they really enjoy food scraps thrown on the ground by people and pets. They are also extremely fond of what your dog leaves behind, both before and after dinner when you take him for a walk (yes, excrement). “Rats will eat nearly any type of food, but they prefer high-quality foods such as meat and fresh grain.” They will seek out fresh vegetables or fruit from a garden only if they can’t find any of their preferred food.  

How to Control Rats

Rats will come into gardens and houses for a number of reasons. First and foremost,rats are always on the look out for food (foraging), and if they find food, they will seek shelter and “move in,” setting up residence under decking, sheds, or nice, warm, unmanaged compost heaps – and then breed. Rats will NOT come into your garden if you do the following:  

• Practice Good Sanitation
• Provide NO Shelter
• Deprive them of Preferred Food

Follow these tips to reduce the chances of having rats establish themselves in your garden:

1. Eliminate standing water. Ensure that drains are in good condition and working properly.  
2. When feeding birds in your garden, use a bird feeder and make sure that any food that falls to the ground is cleared away daily. You may even choose to stop feeding the birds in your garden for a period of time, especially in the summer. This will encourage the birds to munch on the insects and the naturally occurring seeds and berries from your garden’s trees and perennials.
3. Don’t leave food lying around on the ground in your garden for wildlife, including outdoor cats. 
4. Ensure that dog, cat, or other pet foods are not left unattended and remove the bowls for cleaning as soon as they are empty.
5. Clean away spillages of food as well as excrement from rabbit, guinea pigs, bird and pet cages and where possible ensure that they are raised off the ground by at least 8″ and positioned on a hard surface, this will enable you to clean under them thoroughly and frequently.
6. The compost heap offers warmth and shelter but is not a food source for rats unless high protein, cooked foods – meats, oils, and fats, as well as grains, eggs, cheese and dairy products­ – are added to the compost. NEVER add these things to your open compost bin. Limit food waste to raw vegetable and fruit scraps, and coffee/tea grounds. Mix in ample amounts of plant material and leaves. Where possible use an enclosed composting unit. If the compost pile is not enclosed, be sure to turn it frequently to maximize heat and speed decomposition. Please read the Chicago Compost Ordinance to familiarize yourself with the rules and regulations governing the construction of bins and the management of organic garden wastes. 
7. Sheds and other structures should be constructed so that rats cannot gain access. Particular attention should be paid to any gaps around the door and ground. Rats and mice can enter through very small spaces – eliminate all gaps!
8. Ensure that gardens do not become overgrown. Don’t allow clutter and rubbish to build up in the garden. Lumber, bricks, rocks, palettes, and piles of seemingly harmless garden supplies can provide shelter for rats to live in and under.
9. Inspect garbage containers near your community garden and make sure they are not over-flowing. The tops should be closed and not accessible by rats or other animals roaming around.  It is the waste in a garbage can that rats like best, so close the can and keep the rats away! For damaged bins where rats have gnawed holes, contact your ward alderperson to request replacement bins. 
10. Clean up the refuse and garbage lying around in your alley and in any empty sheds or buildings in your neighborhood. Get rid of old mattresses and furniture promptly. Good sanitary practices will not eliminate rats under all conditions but will make the environment less suitable for them to thrive. 

What Should I Do If I See A Rat (or what I think is evidence of a rat) in My Garden?

First, don’t jump to the conclusion that gnawed or missing vegetables are the result of the presence of rats. Squirrels are more than likely responsible for stealing your vegetables and then leaving the evidence behind just to irritate you. Other city wildlife, like opossum, groundhogs, raccoons and rabbits are also responsible for eating your precious vegetables. And yes, there are a lot of these wild animals in Chicago!

First, don’t jump to the conclusion that gnawed or missing vegetables are the result of the presence of rats. Squirrels are likely responsible for stealing your vegetables and then leaving the evidence behind just to irritate you! Other city wildlife, like opossum, groundhogs, raccoons, and rabbits are also responsible for eating your precious vegetables. And yes, Chicago community gardeners experience wildlife contact with a variety of creatures!

By following the above suggestions, you should be able to eliminate the things that will attract rats, which is the cause of the problem. However, if you’ve addressed all of the suggestions above and still have a rat presence, you may want to consider additional tactics:

• Deconstruct existing nests and burrows by collapsing tunnels. Consider adding deterrents to holes such as steel wool, mothballs, or dog hair.
• Plants with a strong fragrance such as marigold, mum, citronella, daffodil, garlic, and mint could help deter rats.
• The presence of feral cats can be an effective way to deter rats. There are programs in Chicago that help place spayed/neutered feral cats in gardens and other sites with rat infestations. Caring for feral cats is a serious responsibility. It’s a multi-year commitment, much like a house pet. It’s also important to note that feral cats can be major predators of small birds.
• Use abatement methods such as traps and bait very cautiously and never place them near areas where food is grown or where people and pets are present.

As your garden members discuss the tactics above, keep in mind that the goal is to maintain the health of the ecosystem and preserve life. Traps and bait do not discern between rats and other wildlife. Prevention is the key! Deterrents are preferred over abatement. Abatement may work to reduce numbers temporarily, but it is not a sustainable solution.

Conclusion: Remember that rats need three things: Food, Water and Shelter.

If you eliminate the standing water and the food that rats prefer and don’t provide places where they can find shelter…you won’t have a serious problem with rats. And at the same time you will minimize the problems with other unwanted wildlife including insects.

More Rat Resources

• Please read the Chicago Compost Ordinance to familiarize yourself with the rules and regulations governing the construction and management of organic garden wastes.
• All composting operations, especially those including food scraps should be done in an enclosed composting system. Review the Chicago Home Composting Guide for details.
• Gardeners at Brickyard Garden in Woodlawn manage a feral cat colony as their primary rat defense. Gardeners provide the cats with modest shelter and food. In turn, the presence of cats keeps the rats at bay.
• The Brooklyn Botanic Garden offers several helpful tips on rat reduction, too.

Sources of information for this summary include:
(1) Entomologists at the Illinois Department of Public Health, University of Illinois, Illinois Natural History Survey, and Purdue University. For additional copies of their original document, contact your unit office of the University of Illinois Cooperative Extension Service. Urbana, Illinois 1995. Issued in furtherance of the Cooperative Extension Work Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Dennis R. Campion, Interim Director, Cooperative Extension Service, University of Illinois at Urbana-Champaign. – Entomology Fact Sheet, NHE-PH-1, Revised 4/96
(2) British Councils guide to rats in gardens
(3) Experiences of many Chicago gardeners over many years

Emerald Ash Borers

• Many parkway trees are ash (fraxinus). They offer beautiful fall color to many City streets. Unfortunately, the Emerald Ash Borer (EAB) has created a serious threat to the future viability of the Ash tree. Learn how to identify an EAB infestation Emerald Ash Borer FAQs.
• The Bureau of Forestry offers a City hotline for reporting potential EAB infestations. Contact 312-74BEETL or 312-742-3385 or visit the City of Chicago’s Emerald Ash Borer guide