Tomato problems? You’re not alone!

Concentric cracking of tomatoes
Concentric cracking of tomatoes

We are at the peak of tomato harvesting and enjoyment time in Maryland. But many gardeners are unhappy, to varying degrees, with the quantity and quality of the fruits of their labor. Those tomatoes we waited so patiently for may have disappointing spots, rots, cracks, and holes.

Before we get into the specific problems, let’s agree that we cannot expect all of our fruits to be perfect, no matter how much time, money, and effort we invest. It’s a garden, not a climate controlled factory. Weather and climate change, soil and sunlight, cultivars and spacing are just some of the many factors affecting plant growth — and they change every year.

This is a good time to think about what we can do next spring to get more out of our tomato plants next year. Picking fruits when they begin to change color from green will increase the number of usable fruits. It allows you to get your fruits off the vine before problems strike. Ripen them indoors on a counter or in a box, basket, or bag. I think you’ll find they taste just as good as their “sun-ripened” sisters.

Common Problems with Tomato Fruits

1. Cracking

Longitudinal cracking on tomato
Longitudinal cracking

Problem: Tomato skins thicken and harden as they enlarge and ripen. They crack easily with rapid and large changes in fruit temperature and water availability. Excess nitrogen is another contributing factor. Significant cracking occurs after thunderstorms. Fruits with poor leaf coverage are especially susceptible.

Cuticle cracking (rain checking) on tomato
Cuticle cracking (rain checking)
Radial cracking on tomato
Radial cracking

Solution: Water around the base of the plant. Cover the soil with an organic mulch. Pick fruits when they start to turn color.

2. Spots From Stinkbug Feeding

Minor stink bug injury on tomato
Minor stink bug injury
Extreme fruit injury of tomato
Extreme fruit injury

Problem: Several different stinkbugs feed on tomatoes. They feed using piercing-sucking mouthparts and leave behind white to yellow corky spots.

Solution: Stinkbugs are widespread and difficult to handpick and control. Minor damage can be cut out with a sharp knife.

3. Sunken Spots With Rings

Anthracnose on tomato

Problem: Anthracnose is a fungal disease that affects ripe and over-ripe fruit. Sunken spots enlarge, concentric rings develop, and tan to black spots emerge followed by salmon-colored spores.

Solution: This disease occurs naturally throughout the state and all tomato fruits are susceptible. Prevent the problem by harvesting fruits when they first turn color.

4. Caterpillar Holes

cutworm on tomato
A climbing cutworm on tomato
Caterpillar feeding on tomato
Caterpillar feeding on tomato

Problem: Caterpillars also like tomatoes! Fruitworms can ruin fruits by feeding all the way to center of your fruits. Luckily, caterpillars are typically not a major problem for tomato gardeners. In many cases they “take a bite” and leave.

Solution: Handpick hornworms and cutworms when you see them. Cut out the damage from minor feeding. Harvest fruits when they start to turn color.

5. Frost is Coming!

Green tomatoes

Solution: Pick all of your green tomatoes before the first hard frost. Those with a white star on the bottom will eventually ripen indoors. There are lots of wonderful green tomato recipes for the rest. My favorites are fried green tomatoes and green tomato pickles.

Visit the Home & Garden Information Center website for more tips and resources for growing great tomatoes.

By Jon Traunfeld, Director, Home and Garden Information Center 

6 thoughts on “Tomato problems? You’re not alone!

  1. Joanna Johnson August 22, 2017 / 4:13 pm

    I agree — this has been the worst tomato year for me in the last decade. We started the season with a rain deficit and then had a very wet August. My tomatoes are all cracked, and not as sweet as last year. I am growing Orange Banana, an heirloom paste variety that makes a divine sauce (not good for fresh eating at all) but I am seriously considering switching to hybrid varieties next year. I lost so many fruits to BER earlier in the season that I’m looking for something more resistant and reliable. But I will miss that taste!

    • Jon Traunfeld September 7, 2017 / 10:05 am

      I have had a fair bit of cracking at the tops of fruits with my paste tomatoes. I think it would have been worse though if I hadn’t picked them when they first start to turn color. I think the flavor and texture are fine when they ripen indoors.
      To prevent BER next year try mixing about 1/3 cup of gypsum with the soil of each tomato planting hole. The calcium in gypsum is readily available.

  2. Kate C. September 6, 2017 / 1:54 pm

    I’m glad it’s not just me this year!

  3. David Arnold September 6, 2017 / 2:30 pm

    For once, I was NOT affected by this much. I’ve scaled back my number of containers (moved to an apartment), and was dutiful about watering this year. The only time I’ve had better luck was when I had my drip irrigation system in place a couple of years ago.

    I think the key is trying to keep the amount of moisture as constant as possible; I didn’t flood them each morning, but rather watered enough to have standing water in the pot (quickly absorbed/drained), and never had a lot of water in the pot’s saucer. Previously I’d flooded the pots each morning, but also would miss days when I was not around (vacation, etc.), so it was “feast or famine”. The key is consistency, and don’t overdo the water.

    I’m loving my yellow tomatoes this year – so sweet! I just wish I could find more varieties that are determinate. Suggestions are welcome!

  4. jontraunfeld September 7, 2017 / 10:18 am

    ‘Celebrity’ is a very reliable determinate cultivar that grows to 3 ft. in height. I have not tried it in containers but expect it would do fine- one plant per 5 gal. container.

    • David Arnold September 7, 2017 / 10:50 am

      I’ve grown it before, but I’m looking for more yellows; they’re sweeter in general. I grew Sweet Tangerine (from Burpee) this year, which were delicious, but it’s pretty much done now. 🙁

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