Tomato plants are mostly annuals as they don’t hold up well to frost. Even a light frost can be enough to kill tomato plants. Some can be overwintered, however, it’s generally best practice to winterize vegetable gardens by pulling old plants out and adding mulch over the soil.
By the end of the season, it’s not a good idea to leave them in their spot to wither away, drop their leaves, to be left to decompose right on top of your mulch. That’s likely not going to end well given the numerous diseases tomato plants are prone to.
Common practice is to tear the plant up – roots and all – and toss it in the garbage.
What a waste!
There’s life in the old plants yet.
5 Things to Do with Old Tomato Plants (and how to get one last great harvest)
1. Composting old tomato plants
Composting old tomato plants isn’t the best idea because of the numerous diseases they’re prone to. If you’re confident that the entire plant is disease-free, there’s no harm in tossing it in the compost pile.
The thickness of the stems can mean it takes a long time to break down. Speed up the process by shredding the plant first, or chopping it into as small of pieces as you can.
To get rid of soil-borne pathogens, hot composting is the only method that will work. The temperature needs to reach 150 to 160 degrees Fahrenheit for more than a few days.
If you aren’t using a hot composting method, the next best thing with any diseased tomato plants is to throw them in the garden incinerator. Rather than getting compost to use elsewhere in the garden, you’ll have ashes that can be added to boost the nutrients in the soil.
2. Cut it down and leave it be
Lazy gardeners and those interested in sustainable gardening methods love this approach. At the end of the season, cut the plant down to just above the soil level and leave the roots in place.
Cold winter weather usually kills the roots anyway. But, over the winter, there’s a whole ecosystem in the soil consisting of worms, caterpillars, larvae and more.
Decomposing plant matter provides them food throughout the winter months.
3. Dig a trench and bury it
A similar approach to composting is to dig a trench and let the composting happen directly in the garden bed. For this to work, you need lots of green matter mixed with small twigs.
Dig the trenches where you’re going to be planting, then fill it with all your old plants at the end of the season, rather than trashing them.
Think of it as early prep for next year’s garden bed. Even if you aren’t planning to use the same spot next season, have a look around your yard and may see spots that could be doing with extra nourishment. Those are the spots to bury old plants then leave nature to take care of the rest.
You can do this with diseased leaves too. You just won’t be able to plant vegetables in it for a few years. For patches in your yard where you don’t plan to grow edibles, give your old tomato plants a burial.
3. Don’t let a cold snap ruin your harvest
Don’t let a surprise early freeze ruin your last harvest. If the forecast warns of an incoming snowstorm, and you don’t have enough fleece blankets for all your plants, any green tomatoes can be picked and made to ripen off the vine.
There are several ways to ripen green tomatoes. So long as they receive the light and temperature they need, they’ll ripen. If you don’t mind mess, rip the whole plant out and hang it upside down from its roots in the shed.
There’s no need though. Leave them on the windowsill and natural sunlight will will suffice. The temperatures by the end of the season are unlikely to be strong enough to burn the skins of tomatoes.
4. Save some seeds
Some tomato varieties are extremely resilient. You can find that if you’re late to cutting down your old tomato plants, it’ll still put out one last fruit. When tomato plants are dying, it focuses energy on fruition. When you see that happening, honor it’s efforts and save the seeds to bring it back next season.
To save tomato seeds, cut it open and empty the juice and seeds into a sieve. Leave it there for a few days and you’ll see a mold form. You want this to happen to tomato seeds because they have a gelatinous coating on them.
Once that forms, rinse it thoroughly, set the seeds aside on a piece of paper towel to dry, and then store them in a paper envelope somewhere dark. Sow them next spring.
5. Make a Winter Wildlife Habitat
For the winter, wildlife are on the hunt for shelter. Old thick-stemmed tomato plants and similar old plants that would be destined for the compost pile could be just the shelter they need.
Use a patch of land that could be doing with extra nutrition from the decomposition of waste organic material, lay the layers of leaves first, then pile up the stems. Smaller animals can take up shelter and hide away from predatory animals that would eat them for breakfast.
Topping off tomato plants near the end of the season
Remember earlier it was mentioned that when tomato plants are beginning to die off, that they throw their energy into fruition? Use that fact to your advantage by controlling when the plant dies off. You’ll get bigger, juicier tomatoes straight from the vine one last time. Less of those pesky miniature green tomatoes.
Getting that to happen is a trick taken straight from the pruning playbook and it’s called topping off.
All you do is pinch the top of the stem and that’ll stunt its growth. When it can’t grow vertically, it’s going to put leaves out. Thin the leaves out too and there’s only one last area for it to focus and that’s on fruition.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.