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Healthy tomatoes in your garden

After a slow start and curly leaves, my tomatoes have finally hit their stride! Tall and bushy, and loaded with green fruit, I can't wait to see that red blush and bite into my first Early Girl of the season.

My evening garden walk includes close inspection for any early signs of disease in my tomato patch. The various pathogens out there aiming for my tomatoes are just waiting for the ideal time to strike. Hopefully I will keep ahead of them this year, and harvest an enormous crop of slicers, salad and sauce tomatoes to last me through next season. If you, too, are worried about the various tomato pests out there, here are some timely tips to keep your plants clean and your harvest bountiful.

I've gotten many calls about blossom end rot on tomatoes. Blossom end rot is the most common tomato disorder in Minnesota. Tomatoes have a flattened tan or blackened spot on the blossom end of the fruit. This is caused by a calcium deficiency due to inconsistent watering practices. It is particularly common in containerized tomatoes. The good news: plants with affected fruit can grow healthy fruit if watering practices are modified. Regular watering, mulching and proper application of fertilizer will help alleviate this problem.

Many fungal infections also attack tomatoes. These include septoria leaf spot, early blight (alternaria), anthracnose, fusarium wilt, verticillium wilt and late blight. All of these fungal infections affect the leaves and fruit of your tomato plants, and can lay waste to your tomato patch very quickly. Bacterial infections, like bacterial speck and bacterial spot, and the above fungal infections can be transmitted through seed, infected transplants and can overwinter in the soil.

Control measures for bacterial and fungal infections in your tomatoes include:

•Water at the base of the plants in the morning to minimize the amount of time the leaves are wet.

•Allow adequate air circulation between full grown plants in order to help wet foliage dry rapidly.

•Avoid working with plants when foliage is wet to keep from spreading disease-causing microorganisms.

•Keep your tomato patch weed free to reduce the survival of fungus and bacterium.

•Remove as much plant debris as possible in the fall.

•Rotate crops so that tomatoes are grown in the same ground only every three or four years.

•Buy disease free/disease resistant transplants or seed. All those letters after the variety mean your plants are resistant to those particular diseases.

If you spot the beginnings of a fungal or bacterial infection in your tomato patch, apply a copper based fungicide to prevent its spread throughout your garden.

For more information on growing tomatoes in Minnesota, visit the UMN Extension website at, click on garden. Hope you're eating disease free, home-grown tomatoes soon!

Until next time, happy gardening!

"A world without tomatoes is like a string quartet without violins."

- Laurie Colwin, Home Cooking