Tomato's green shoulders
Have you tried to grow tomatoes on your balcony and ended up with hard, green or yellow shoulders at the stem end of the fruit?
This condition is called green shoulder and it can come from conditions that are too warm or if the tomatoes are not sheltered from the sun by leaves.
If your growing conditions are just too hot on a balcony, you can try sheltering the plants with a lattice or some gauzy material that will filter the sun. Buy a large plastic pot saucer and fill it with stones and water. Place the plant on this, keeping the bottom of the plant above the water mark. The idea is to let the action of evaporation cool the air around the plant.
While old tomato hands speak wisely about “pruning” their tomato plants to improve production, green shoulder is one reason why you should leave this to the old tomato hands. Most of us get enough tomatoes without such methods, and issues such as green shoulder can arise when the fruit is exposed to the sun. However, you can safely prune from the bottom of the plant to beneath the first set of fruit as these leaves are doing nothing for the plant but taking up energy.
Also, in late August, you can cut back indeterminate tomato plants (those that keep on growing and growing) to stop further flowering and allow the existing fruit to mature.