Tomato gardening is a rewarding activity that can be done on a small scale in containers or a large scale in the garden. Choose the best seed or garden starters, transplant them properly, keep them warm and watered, and control tomato insects and diseases. Your tomato plants will set fruit in abundance. If they don’t, or the tomato fruit looks unappetizing or begins to rot, here are some tips that may keep you out of trouble.
1. Poor Tomato Fruit Set and Blossom Drop
Nothing feels worse than having a gorgeous garden full of tomato plants—and no tomatoes appear. Blossom drop happens during temperature extremes. If the temp drops below 55 degrees or rises higher than 90 during blossom time, the small yellow tomato flowers drop right off without setting fruit.
You can regulate temperature extremes to some degree by covering with clear plastic or miniature greenhouses when it’s cold and shading the tomato plants, mulching properly, and watering underneath when it’s hot. Evaporation cools the soil and the tomatoes.
Tomato blossoms also drop if the soil is dry or contains too much nitrogen. Water regularly if Mother Nature doesn’t bring rain, and don’t over-fertilize. Balanced fertilizer such as 10-10-10 or 5-10-10 is just fine for tomatoes. Compost and well-rotted manure are even better.
Tomato plants should be fed every 10 days when they’re growing up and every two weeks while blooming and setting fruit. Stop fertilizing tomatoes when the plants stop blooming.
2. Blossom End Rot
Brown mushy spots appear on ripening tomatoes at the blossom end, and they may smell rotten. This can be an icky surprise to an unsuspecting gardener picking fruit.
Tomato blossom end rot is caused by calcium deficiency in the soil. Calcium deficiency can be caused by extreme dry weather, high nitrogen levels, or disrupted tomato roots. Amend the soil with bone meal fertilizer, mulch tomatoes properly to maintain moisture levels, and don’t use too much nitrogen.
Catfaced tomatoes appear puckered up—like a cat might if it just drank vinegar. The fruits have deep crevices but should not appear cracked.
Catfacing starts at blossom time, so if you unfortunately have cool weather your tomatoes will be catfaced. Keep tomato plants warmer by covering with a sheet of clear plastic in the late evening and removing in the morning.
Heirloom tomato varieties are much more susceptible to catfacing than hearty hybrid tomatoes. Although catfacing is ugly and makes tomatoes hard to process, it doesn’t affect flavor in any way. Enjoy catfaced tomatoes in salads instead of trying to can them.
4. Cracked Tomatoes
Cracks in tomatoes may be deep or they might just appear as fine brown lines. The cracks may radiate downward from the stem or surround the tomato around the fruit.
Tomatoes crack when dry weather is followed by wet weather, causing the fruits and plants to grow vigorously. It’s almost the same as stretch marks on a human when he or she suddenly gains weight and the skin stretches beyond its usual elasticity.
Most cracks won’t harm the tomatoes; simply cut them out when it’s time to process or eat the tomato. Deep cracks that trap moisture open the tomato fruits up to fungal infection. Pick those fruits and let them ripen in a cool, dry place.
5. Sunscald and White Shoulders
Sunscald appears as large white or yellow patches on the sides of green tomato fruit, and the tomatoes refuse to ripen properly if left hanging on the tomato vine. White or yellow shoulders appear at the top of the tomato fruit, and are also sunscald.
Limit pruning once the plant is setting fruit. If you’ve had a long period of cloudy days and the sun suddenly decides to shine again, shade your tomatoes with bug netting to prevent sunscald. Move branches with fruit into the shade of other branches if at all possible.
Do You Need to Worry About These Tomato Problems?
You don’t need to worry about these tomato problems too much because they aren’t caused by tomato insects or diseases. The fruits may appear unsightly but they should still be tasty.
Find the root cause of your tomato problems before ignoring them, however. Several tomato diseases mimic blossom end rot, and tomato insect damage may be mistaken for sunscald.
Look your plants over carefully for other signs of trouble such as yellow or brown leaves, wilting, and fuzzy growths that obviously don’t belong on tomato plants.
C J Marshall says
I am loosing most of my tomato crop this year from a fruit problem that involves white filaments growing throughout the fruit and making it tough and nearly impossible to eat. Does anyone know what the condition is and how to deal with it.
Sunburn. My 2016 tomatoes have this problem and I’ve read sunburn is caused by high temps. Try to cover or hide tomatoes on a hot day if the temps go into the 90’s
M Evans says
Tomatoes grow and look OK, but on cutting into tomato there is a largish hard core,rest of tomato perfect to eat
Tom knotts says
Mine to want do I do
Ronnie Hickox says
Tomatoes ripens on bottom but still green on top. What causes this?
Hot days which causes sunburn. Try to shield your tomatoes on hot days.
Ann Engel says
I bought some plum tomatoes in the store and a good half of them had black cores. The outer walls and the center were fine but the area where the seeds and the gel were was literally black like it was spoiled. I was wondering if this was because they were picked too early or not stored properly, or just the strange growing conditions this summer.
What causes the leaves to turn yellow and brown and wilt?