Blossom end rot may look like some type of dreaded bacterial disease, but it is actually a symptom of nutritional deficiency. Affected plants include:
When blossom end rot strikes, your plants are signalling that they are deficient in calcium. Calcium is an important part of the cell walls of fruits and vegetables. When calcium is deficient, the cell walls break down, producing blossom end rot.
Most gardeners don’t realize that the calcium content of the soil is rarely the problem, particularly in states like Kansas that have limestone (calcium carbonate) in abundance. Blossom end rot frequently appears when a plant is unable to take up calcium for some reason.
In most cases, the root of the problem lies with the root of the plant. Both nitrogen-rich fertilizer and cool, wet weather tend to prompt lush plant growth, but very little root growth. When a hot, dry spell hits, the plant will have far more foliage than it can easily support with its meager root system. It will focus its efforts on survival by restricting the flow of moisture and dissolved minerals such as calcium to its fruits, producing blossom end rot.
- Soft, shriveled blossom ends on fruits.
- Brown, dry, leathery patches on bottoms of fruits.
- Secondary fungal infection.
Remove the rotting fruits from the plants. After that, there isn’t much you can do except wait for the plant to regain its water and nutrient balance. How long this takes will simply depend on the weather.
If a soil analysis shows that your garden is truly deficient in calcium, you will need to spread gypsum to correct the problem in the long run. For a temporary solution, you can feed the plants with liquid calcium fertilizer or by burying a calcium carbonate tablet at the base of the plant.
Avoid the overuse of nitrogen fertilizer. The goal is to keep the plant growing steadily so that its root system can keep up with the growth of the top.
While the weather does not always cooperate, anything you can do to provide an even supply of moisture to your plants is helpful. Water consistently during dry spells, and apply mulch to keep the soil moist.
Finally, be careful when hoeing to avoid damaging roots lying close to the surface.