Combat & prevent blossom end rot in tomatoes

If your tomatoes have brown and rotten spots on their ends, it is mostly flower end rot, which is caused by a lack of nutrients.

If your tomatoes (Solanum lycopersicum) develop brown, widening points at the ends of the fruit, you are dealing with the blossom end rot of tomatoes. You have already learned a lot about this nutritional deficiency in our expert interview with Floragard. Here you will find some additional information on blossom end rot in tomatoes.

Recognize flower end rot

Typical symptoms of blossom end rot are the brown or black spots on the tomato fruit set. This means that putrefactive spots are forming exactly opposite the fruit stalk. These spots get bigger and look watery. Above all, they are severely affected Varieties of tomatoesthat produce very large fruits. This includes all kinds of beefsteak tomatoes or ox hearts. Sometimes yellowish discoloration can also be seen on the leaves.

The affected areas on the tomatoes also collapse, dry later and become hard. Starting with the tips, the whole tomatoes will eventually turn black. Especially in the months of June, July and August you have to be careful and keep an eye on the tomatoes. Because if nothing is done about the blossom end rot, the fruits will fall off. The flower end rot can also occur in rare cases paprika (Capsicum) and zucchini (Curcurbita pepo subsp. Pepo convar. giromntiina) occur and shows the same symptoms as with tomatoes.

Blossom end rot and its cause

The cause of this physiological disturbance in tomatoes can be a calcium deficiency or, often, too high humidity. Due to this calcium deficiency, the cell walls contain too little calcium and therefore the cell walls are not stable. The cell walls then collapse, the affected tissue dies and ultimately turns brown.

On the one hand, calcium deficiency can occur when there is not enough calcium in your soil, but an imbalance of other nutrients can also cause calcium deficiency. For example, a high concentration of potassium or magnesium can hinder calcium absorption. If there is little calcium in the soil, this is also associated with a lower pH value. Soils that are too acidic can be brought back into the neutral pH range with liming.

Prevent and control flower end rot

One way to prevent bud rot in your tomatoes is to keep the humidity low to encourage perspiration. This is especially important if you are growing your tomatoes in a greenhouse. Since calcium is transported with the water flow in the plants, transpiration ensures that the calcium is quickly transported upwards. You should also pay attention to an even water supply.

The humidity can also be reduced by increasing air circulation. The circulation can be improved if the population is not too dense. In this way, you promote the transpiration of the individual parts of the plant and lower the humidity, thus preventing flower end rot.

You can also use a calcium-containing fertilizer as a preventive measure. You can find more information on the right one here Fertilizing tomatoes. In solid form, you can use algae lime or rock flour for prevention and control. Just sprinkle it around the tomatoes and carefully pour in. Liming can often result in a deficiency of other nutrients, for example iron, because the pH value changes with liming. You can also bring in calcium in liquid form with calcareous irrigation water or in liquid form Tomato fertilizer use that contain calcium.

Can you still eat tomatoes with blossom end rot?

Since the blossom end rot is not caused by bacteria or fungi, you can in principle eat these tomatoes with a clear conscience. All you have to do is cut out the discolored spots, if they're not already too big, and use the tomatoes as you normally would. However, be careful when using these tomatoes. Because the infected areas are entry gates for fungi and bacteria and can make the tomatoes inedible.

The cut pieces or badly affected tomatoes can simply be composted - so they still serve a purpose. Why each of us one compost should have, find out here. In general, it is better to remove the infected tomatoes from the plant, fertilize them adequately and give them plenty of strength again to produce many more flawless tomatoes.

tip: A suitable supply of nutrients is important for healthy tomatoes. It is therefore best to use a high-quality vegetable soil such as our peat-free soil when planting Plantura organic tomato & vegetable soil.