Ask a handful of gardeners if it’s okay to compost tomatoes and you’re sure to get conflicting answers.
A matter of great controversy, everyone seems to have a different opinion on whether this is an acceptable practice or not.
The truth is that the answer could go either way depending on a number of factors.
Composting tomatoes is indeed risky, but it can be done as long as a few basic criteria are met.
This article looks at the common issues and shares the steps you can take to mitigate potential issues.
What are the risks?
It is true that composting tomato plants can be problematic. If not done correctly, it can lead to all sorts of headaches the following season, which is why many prefer to discard their plants and avoid the practice altogether.
There are several risks associated with composting these plants in particular: possible spread of disease, the growth of unwanted volunteer plants and insufficient breakdown of plant material. Let’s take a look at them all, followed by tips for effectively managing your compost pile.
Spreading disease is the main concern associated with composting these plants.
If plant matter contains pathogens that don’t die during the composting process, those diseases can come back and wreak havoc on next season’s crop.
Many bacterial and fungal organisms can survive on plant tissue in the middle of a mismanaged compost pile. For example, late blight and early blight can overwinter on vines that have not completely broken down.
To safely compost potentially diseased plants, it is crucial that the pile is hot. This means consistent temperatures between 131 and 170°F.
Good composting techniques are important to ensure that plant material is properly broken down and pathogens are destroyed.
Even when done correctly, some diseases such as fusarium wilt, verticillium wilt and bacterial canker can survive the composting process. In general, if you suspect your plants have diseases, it will probably save you some effort to keep those plants out of the pile altogether.
Personally, I hate the idea of throwing plants away.
Instead, I’ve created a second heap far away from my garden where I toss suspect tomato plants, along with weeds, grass, and other vine plant material that doesn’t break down properly, or material that could be filled with unwanted seeds. .
If you have the space, I highly recommend making a second stack with this designation. Just be sure to keep it out of the way and avoid using the finished compost in your vegetable beds.
Volunteers in the garden
If fruit is composted along with the vines, some of the seeds may survive the winter, resulting in seedlings popping up in random spots in the garden next spring.
I always take the fruit off the vines and throw them in the trash instead of my compost pile. To kill the seeds, the compost pile must maintain a temperature above 140°F for two weeks or more.
Depending on your perspective, this can be a good thing… extra tomatoes that you didn’t have to work for!
But don’t get too excited.
While it’s possible to get a healthy yield from volunteer tomatoes, it’s also possible that they won’t produce any fruit at all if you’ve grown hybrid varieties. They can also contain pathogens that can spread to the rest of your crop.
While it is generally recommended to remove stuffed tomatoes, sometimes my curiosity gets the better of me and I grow a few.
While one or two may not be a problem, I would recommend removing volunteers in any areas where tomatoes grew last season, and wherever you plan to grow them this season.
When you see them appearing on your compost pile, simply turn it over and dig it in.
Learn more about growing tomatoes from seed in this guide.
Insufficient decomposition via large, messy vines
Tomato vines are large and may not break down properly if they are knowingly tossed into the compost. Vine compost can not only harbor disease, but is just plain annoying.
To avoid a big tangle of vines, always break the plant material into smaller pieces before throwing it in.
With so many concerns to consider regarding problems down the road, is it ever worth composting tomatoes?
The answer is yes, as long as you have a well-managed hot compost pile that maintains an internal temperature between 131 and 170°F.
Oxygen, moisture and a balanced mix of materials are key.
Good air circulation is crucial, as oxygen is needed to support the beneficial microorganisms that are breaking down the material.
The National Organic Program recommends turning the stack at least five times every 15 days to maintain adequate airflow.
Those microorganisms also need water to survive. Keep the pile damp, but not soaking wet.
It’s also important to keep an eye on what materials you’re adding, and try to maintain a balance between “green” nitrogen-rich material and “brown” carbon-heavy material.
In general, you want to keep a ratio of three to four parts “brown” to one part “green”.
If you add food scraps, green plant material, or grass clippings to the pile, make sure you also add some dead plant material, leaves, or straw, and vice versa.
Depending on your methods and management practices, it can take anywhere from three months to a year to completely break down the material into usable compost.
For more information on the basics of composting, check out this guide.
Don’t be afraid
You can decide for yourself whether it is worth composting those tomato plants. If you choose to go for it, remember to abide by the following rules:
Waste or separate material showing signs of bacterial or fungal disease. Break up large pieces before throwing them in. Keep your pile warm and active by maintaining good airflow, moisture, and a balance of green and brown materials.
Tomatoes, like other plants, can certainly be broken down into nutrient-rich compost. It just takes a little extra attention and care to get it right
Do you compost or dispose of your tomato plants? Share your challenges and successes in the comments below!
If you’re in the mood for more composting ideas, be sure to check out our guides.