Tomatoes are home gardeners’ favorite vegetable, by a mile. But from their roots to their fruits, they sure are susceptible to a plethora of problems. It’s the rare summer that ends with healthy, disease-free plants and ripe, unblemished tomatoes, especially in the hot and humid mid-Atlantic.
And nothing is more frustrating than reaching the harvest stage, only to find there’s something wrong with the tomatoes themselves.
When weeks of tender loving care culminate in tomatoes that don’t ripen, or are blotchy, scarred or diseased, it’s tempting to throw in the towel and head to the farmers market.
Some of these problems are caused by disease, some by cultural practices, and some by environmental issues beyond your control. The good news is that a fruit may look less than perfect but still be edible, even delicious. By familiarizing yourself with the most common tomato fruit problems, and what to do about them, you up your chances of harvesting flavorful – if not the most beautiful – tomatoes.
Cut out the bruised areas and enjoy the rest of the tomato. Since bruised and overripe tomatoes tend to be softer in texture, take that into consideration when choosing how to prepare them. But if you spot mold, it’s time to toss the affected tomatoes.
Black or Brown Watery, Sunken Ends
This is blossom end rot, caused by a lack of calcium in the soil combined with fluctuations in the amount of water a plant receives. Roma-type tomatoes are especially susceptible to BER.
To prevent it, get a soil test to be sure your soil has the right amount of calcium. Be consistent with watering; don’t let plants get wilty-dry. Spread mulch over the soil to hold in moisture.
Can I eat it? Yes. Since BER is a cultural problem and not caused by disease or fungi, the unblemished part of the tomato is still edible.
Cracked or Split Skin
Cracking is when the inside of a tomato grows faster than the skin, splitting it open. It happens when a plant gets too much water at one time. The cracks can run vertically or in a circle around the fruit. It’s commonly seen on beefsteak types, but any kind, including cherry tomatoes, can crack.
To prevent it, try to keep to a consistent watering schedule so plants don’t get water stressed. You can’t always prevent cracking – a drenching rainstorm can cause it – so if bad weather is expected, pick almost-ripe fruit and let it finish ripening indoors. Crack-resistant varieties are also available.
Can I eat it? Yes, as long as the crack is clean, isn’t moldy and doesn’t ooze or smell bad. Eat it immediately, however, because cracked tomatoes start to rot in a day or two. Never eat a tomato with mold on it.
When we’re wounded, our bodies create a scar. Same with tomatoes. Brown corky lines or healed splits are indications that the growing tomato was injured at some point. Larger tomato varieties and heirlooms are particularly susceptible to scarring.
A tomato with catfacing will be deformed, with large corky scars on the blossom end. Researchers aren’t sure why it happens but theorize that cold or fluctuating temperatures when a flower is fertilized, or too much nitrogen, may cause it. Like scarring, large and heirloom varieties are more prone to catfacing, and there is no known way to prevent it.
Can I eat it? Yes, as long as mold hasn’t set into the scarred areas. Cut the scars away, as their texture is unappealing.
This is when the top part of the fruit stays hard, doesn’t ripen, and remains yellow or green, even if the rest of the fruit is red. The flesh inside doesn’t ripen either, and stays white and hard. No matter how long they stay on the vine, they never finish ripening. Heirlooms are more likely to suffer from yellow shoulders.
When it happens, it’s usually after a period of hot (90+ degrees) days. Scientists don’t know what causes yellow shoulders but think it may be an interplay between soil health, the type of tomato and viruses. It can’t be prevented or cured. Making sure your soil is rich in organic matter, has the right balance of nutrient, and is at the proper pH can create the conditions to make it less likely.
Can I eat it? The top part won’t be palatable, but the ripe lower half of the tomato should be fine.
Sunscald looks like pale or white patches on the part of the fruit most exposed to the sun. It’s a cultural problem that occurs when fruit gets too much sun during the hottest part of the season. It often happens on plants that have been severely pruned back or have lost leaves due to disease, because there isn’t enough foliage to shade the developing fruit.
You can’t cure sunscald once a tomato has it, but to prevent it, cover plants with shade cloth, move container plants to a shadier area during the hottest part of the day, and, if pruning tomatoes, try not to remove too many leaves.
Can I eat it? Yes, simply cut off the sunscalded area.
Tomato fruits can get anthracnose, bacterial rot, bacterial canker, botrytis, and various blights. These look like black, brown, yellow or white spots on the skin or rot inside the fruit.
To lessen the chance of disease, start by choosing varieties labeled as disease resistant. Practice good sanitation; remove dead or diseased foliage promptly. Mulch to help keep bacteria and fungi in the soil from getting on your plants. Make sure plants have good air circulation. Don’t overhead water. If growing tomatoes in containers, don’t reuse potting soil. It can harbor disease. Use organic fungicides as a last resort.
Can I eat it? If the disease is only on the plant but not on the fruit, then yes. If the tomato itself is diseased, no. The fungus or bacteria causing the lesions may not hurt you, but other pathogens and fungi can enter the diseased area and may be harmful.
After months of anticipating enjoying a perfectly ripe, luscious tomato, you may be tempted to wash off or slice away a moldy or diseased area. Don’t do it. Tomatoes that have mold on or in them are not safe to eat, whether fresh or cooked. Disease can also lower a tomato’s pH, making it less acidic, which is why Penn State Extension advises against canning any tomatoes that show signs of disease.
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BEWARE IF YOU EAT TOMATOES: Watch This Video First
FAQ
When should you not eat a tomato?
How do you know if tomatoes have gone bad?
Is it OK to eat shriveled tomatoes?
Is it OK to use overripe tomatoes?
Should you eat tomatoes?
For most people, there’s little reason to avoid tomatoes. Rather, it’s quite the opposite. Tomatoes can be part of your overall produce intake because of their healthful nutrients and compounds, such as lycopene, beta carotene and vitamin C, all of which act as antioxidants and exert anti-inflammatory effects in the body.
What is a safe amount of tomatoes to eat on a daily basis?
Choosing ripe tomatoes, and adopting some heating/cooking process to consume them, such as roasting or making a sauce. This, in addition to improving the bioavailability of lycopene, decreases that of solanine, which is a toxic alkaloid if consumed in large quantities.
Are ripe tomatoes safe to eat?
If only one tomato in the bunch is moldy, compost or discard it and inspect the others for use as soon as possible. Overripe tomatoes will be on the soft side all over and more difficult to cleanly cut. However, they’re still perfectly safe and delicious to eat! Do tomatoes on the stem last longer?
Can you eat tomatoes if you have disease?
Disease can also lower a tomato’s pH, making it less acidic, which is why Penn State Extension advises against canning any tomatoes that show signs of disease. When tomatoes turn blotchy, scarred or diseased, your first instinct may be to throw them away, but some are still safe to eat.