Is Vermicomposting Tomato Plants a Good Idea?

article image
Photo by Fotolia/bufka
You shouldn’t compost diseased tomatoes that that show signs of blight or Septoria leaf spot.

I was told not to compost tomato plants for some reason — I can’t remember why. Are they OK for vermicompost?

The only reason we don’t compost tomato plants is if they’re diseased, especially if they’re infected with late blight, which is fatal. The problem is easy to identify because every part of the plant is affected, fruit included. The stems often show signs of blight first — they turn black at the top — and then the fruit and foliage follow. Luckily, late blight isn’t as prevalent as early fungal issues, such as Septoria leaf spot and early blight, which slow down plants but rarely kill them. Both of these diseases are soilborne, and they turn the leaves yellow and spotted, starting at the bottom of the plant and then working their way upwards.

A plant with late blight should not be composted. The disease can overwinter in a compost pile or in a vermicomposting (worm composting) system. I wouldn’t want to compost diseased plants for fear of perpetuating the problem.

If plants are healthy at the end of the season, they can be safely composted or used for vermicomposting.

For more advice from Doug Oster, see:

Attracting Beneficial Insects with Pollinator Plants
Expert Gardening Advice for Growing Root Vegetables

Feeling stumped? Write to us!

All of this issue’s questions were submitted via Facebook. For a chance to see your gardening question answered in print, email it to, post it on our Facebook page, or share it on Instagram with the hashtag#HeirloomGardener.

Doug Oster is the home and garden editor at the Pittsburgh Tribune-Review and is co-host of The Organic Gardeners on KDKA radio. Doug’s book Tomatoes Garlic Basilcontains even more useful information.

Mother Earth Gardener
Mother Earth Gardener
Expert advice on all aspects of growing.