Tomato Quirks

Sometimes a tomato doesn’t turn out looking like you’d expect. Here are some odd things you might see that are caused by neither insects nor diseases.

Bizarrely shaped fruit. Also called catfacing, this has nothing do with cats; the word describes puckering or misshapen fruit. It can happen to strawberries and tomatoes exposed to temperatures below 50 degrees when in bloom or setting fruit. The cool weather interferes with pollination and can cause the blossom to stick to the developing fruit, which keeps part of the fruit from developing. Meanwhile, another part does develop, so you end up with weird-looking and scarred fruit. It is most common on large-fruited types.

Split skin. When a tomato fills up with water too fast, usually after a dry spell, the skin can split. Some varieties are “crack resistant,” which means they don’t split easily, but none are crack proof. If you harvest and eat fruit with cracks right away, it will be okay. Left on the plant, it will be discovered by little beetles or will rot.

Sunscald. Tomato plants protect their fruit with an umbrella of leaves. In bright, hot weather, fruit exposed to the sun may develop a scalded, or sunburned, spot. This is most common on green fruit. At first a yellow patch appears on the part of the tomato that is in hot, direct sunlight; when the fruit ripens, it forms a gray spot with a papery surface. This is not a reason to avoid full sun unless you live in a desert climate, where a little afternoon shade is okay. Tomatoes have enough foliage cover to avoid this problem on most of the fruit.

Sunburned leaves. If your brand-new tomato plants suddenly developed gray-white blotches on the leaves in hot and sunny weather shortly after planting, it could be a simple case of sunburn. The plants may have been in the dark on our truck and then in the shade at the store for a few days. When suddenly set out in full blazing sun, the leaves can burn. Don’t worry: the plant will recover. Isn’t it interesting that leaves, like our winter skin, may react to that first sudden burst of sun?

Green shoulders. Some tomatoes naturally keep a little green coloring at the top, or “shoulder,” of the fruit. This is a genetic trait. Pick the fruit when the rest of the fruit looks ripe. This is most common in heirlooms and older hybrids.

Bumpy stems. You may see lots of little raised bumps on the main stems that trigger your alarm bell. This is usually nothing bad. It’s just the “root primordia,” or earliest stage of a root that would develop if the stem were underground. They are most common in wet weather. Occasionally the bumps signal underground root damage, so watch the overall health of the plants.

Blooms fall off. If spring weather is too cool, or a summer heat wave sets in, the blooms of tomatoes may drop. Things will improve when the temperature gets back to normal. Normally tomatoes need temperatures between 55 and 75 or 80 degrees to set fruit, but Bonnie’s varieties are specially bred to take a little more punishment. You may plant early varieties (such as Early Girl) and extra heat-tolerant varieties (such as Heatwave and Sweet 100) if weather extremes are typical where you live. See our tomato varieties page for tomatoes best adapted to cool or hot climates.

Bottom of tomato rots. This is probably blossom-end rot, a condition that has several causes and is common in dry weather. Read more about in the tomatoes section of the Learn & Grow Library.