Don’t get discouraged. All beginner gardeners have learning hurdles and even experienced gardeners never stop learning! We’re not sure where you live—and we wonder if it’s in a warm place. Here are a few common reasons for soft tomatoes:
1. If tomatoes are soft, usually it’s just overripe and you want to harvest sooner.
2. Or, if the temps have gone over 90 degrees and you let them fully ripen on the plant, they can become mushy.
3. Did you overfeed the tomatoes? This is most likely is a nutrient imbalance, most likely too much nitrogen. Too much fertilizer with nitrogen or not enough potassium can be an issue. If you buy a fertilizer, be sure to apply a 1:3 nitrogen-to-potassium liquid fertilizer.
We’re not sure why the tomatoes are smaller than you expected. Is it a ripening issue? Temps above 85*F and under 55*F will affect the ripening of tomatoes. If the temp is too low, the tomatoes can freeze overnight, causing them to become mushy as they thaw the next day (this is a sign of decay and means they are not safe to eat).
Did you get enough sun? Tomatoes need a LOT of sun: 6 to 8 hours a day. Or, if it’s just size, that could be due to lack of moisture. You could also help growth by removing the small tomatoes and the stems and leaves that are offshoots to help channel energy into the rest of the tomatoes.