Tomatoes need an additional source of nutrition during the flowering period. Mineral or organic fertilizers are suitable.
As for the first category, you can choose superphosphate and potassium salt.
It is important not to overuse nitrogen fertilizers, which promote active growth of tops, but not fruits.
Natural fertilizers are considered effective.
For example, yeast fertilizer is popular and is very easy to prepare.
You only need to dilute 100 grams of raw yeast in a liter of warm water, and then mix it with a bucket of water. After that, you need to move on to watering. This amount of fertilizer is enough for 15 tomato bushes.
Another excellent remedy can be made from wood ash.
You only need one tablespoon of ash per bucket of water. Every week it is enough to pour half a liter of fertilizer under each plant.
Iodine will also help you get an excellent harvest.
To do this, you need to dilute just 10 drops of the preparation in a bucket of water, and then carry out root treatment.