Ways to Prevent Tomato Disease in Your Garden

cherry tomatoes in a bowl

Tomatoes might be the one vegetable (or fruit!) that most of us gardeners grow each season. Juice from a ripe tomato dripping down our chins is a celebration of summer!

This love for tomatoes can make it especially frustrating when they’re struck by disease. Unfortunately, in many locations there’s a long list of diseases that attack, and often kill, our beloved plants.

Most of the diseases are fungal in nature and are often hard for the untrained eye to tell apart. The good news is there are some things you can do in your garden to decrease the negative impact these diseases have on your summer harvests.

I like to call them “best practices” because this list should become part of your regular gardening routine every year. If you love your tomatoes, incorporate as many of these as possible to protect and support your plants in fighting off disease.

garden tomatoes in a bowl

Best Practices for Preventing Tomato Diseases

Plant disease resistant varieties.

If you have a particular disease that affects your garden, look for and plant resistant varieties. When you’re shopping for seeds in winter, check the variety listing in the catalog. Each description should list what, if any, diseases it’s resistant to.

Johnny’s Selected Seeds has a key at the beginning of the tomato section of their catalog that lists abbreviations for 18 different tomato diseases. These abbreviations can be found next to the variety name if they’re resistant to it.

I also have an article about the best tomato varieties.

Rotate your plants. 

Tomatoes are in the Solanaceae family, which also includes other garden favorites like peppers, eggplant, potatoes, and tomatillos. Do not plant anything in the Solanaceae family in the same place in your garden year after year.

For example, if you planted a garden bed full of tomatoes one year, the next season you shouldn’t plant any of the members of this family in that bed. Rotation is about plant families, not just each individual vegetable. Put as many years as possible, three to five or more, between family plantings.

Pull out volunteer tomato plants.

Tomato plants volunteer very easily from last year’s fallen fruit. If you struggle with disease in your garden, know that these volunteer plants may be carriers of the diseases you’re trying to avoid. It might be best to yank them out instead of taking the risk of spreading last year’s disease.

hands holding colorful garden tomatoes

Mulch your tomatoes.

Many of the tomato diseases spread by water splashing up onto the plant from rain or watering. Vegetable garden mulch around the base of your plants with hay, straw, leaves, or grass clippings to minimize splashing.

Water at the base of the plant.

Fungal diseases favor wet and warm conditions. Try to keep your tomato plant as dry as possible. Water your plants at the base with drip irrigation, a hose with a wand, or a watering can. Don’t use overhead watering like sprinklers on tomatoes.

More tips for watering your vegetable garden the right way.

man watering garden

Don’t work with your plants when they’re wet.

The best time to harvest tomatoes is not after a big rain storm. Your wet hands could spread disease from plant to plant. Wait for your plants to dry out before harvesting, staking, trellising, or pruning.

Keep plants off of the ground.

All of your tomatoes should be staked and/or caged to keep them up off the soil (where many diseases start) and improve air circulation. I prefer to make my own DIY tomato cages. And get tips on how to use tomato cages.

Prune your plants.

Pruning indeterminate tomatoes is an effective technique to open them up and help them dry out more quickly after rainstorms.

Check out this popular video I filmed in my front yard garden while pruning my tomato plants!

Remove diseased leaves. 

Many of the tomato diseases start at the bottom leaves and slowly work their way up the plant. If you notice diseased leaves you can remove them to try to slow the spread.

Do a thorough fall cleanup.

And finally, if your plants suffer from disease throughout the season, make sure you clean up your garden in fall and dispose of all plant debris. I put my tomato plants out for my city’s yard waste collection because I don’t want to put them in my compost area at home.

Depending on where you garden, there might be a lot of diseases working against you and your tomatoes. But, the fact that you choose to plant them each year anyway shows how much you love them. Me, too! It’s definitely worth the risk of potential heartache!

Now, I’d like to hear from you. What “best practices” are on your garden to do list? How do you prevent disease in your garden?


More posts about tomatoes:

How to Prune Your Tomato Plants

The Best Tomato Trellis

How Many Different Varieties Should You Plant?




  • Great tips. I took your advice from one of our interviews and used a lot of mulch (I saw that was one of your tips above). Currently I am using organic liquorice root as my mulch. It’s cheap around here and readily available.

    • Hey Mike! Great to hear from you. I hope the mulch is helping you weed less this summer. Let me know if you notice a difference.

  • Fascinating read!

    This is useful information as I start work on my tomatoes.

  • Hi, thanks alot for this guiding information on how we can prevent tomato diseases, what do i have to first as a new young farmer on a small piece of land? Thanks. Gond day. #cephaswamala

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