Why Are My Grape Tomatoes Splitting Open While on the Vine?

Grape tomatoes are a variety of miniature tomatoes. They are often determinate tomatoes, meaning that they grow on a plant that is bushlike rather than vining. As well, grape tomato plants tend to set all of their fruit at once. What causes splitting in grape tomatoes is similar to what causes it in regular-sized tomatoes. The breed of tomato as well as the growing conditions will often have a strong effect on whether or not the tomatoes split.

There are two ways that grape tomatoes will split while they are still on the vine. The first is a concentric splitting pattern, where the split occurs on the circumference of the tomato. The second type of splitting is radial, where the split runs from stem to bottom. Both types of splitting can occur when the tomato has ripened on the vine or when the tomato is still green.

Certain breeds of grape tomatoes are more resistant to splitting while still on the vine. Other varieties have skins that are less elastic, so when there has been uneven growth in the tomato plant or a growth spurt, the skin of the tomato cannot handle the sudden change and will split. Hybrid breeds of grape tomatoes have been bred to be more resistant to splitting.

Irregular watering or irrigation methods can lead to splitting in grape tomatoes. Irregular watering causes grape tomatoes to split because of the sudden influx of water in the fruit. In overwatering, the fruit is not used to large infusions of water, so it splits as the skin of the tomato is unable to hold all of the liquid. Irregular irrigation will also cause other problems for the grape tomato plant, including wilting, yellowing of the leaves, blossom end rot and root rot.

Controlling splitting tomatoes can be done by purchasing a variety of tomato that has been bred to be split or crack resistant. A regular irrigation schedule also prevents cracking. Regular moderate watering is better than irregular watering, and it produces a healthier plant overall. Split or cracked grape tomatoes can be used, as long as the split has not become infected. Use the split tomatoes in sauces, stews or salsas, where their irregular shape is not an issue.