Tomatoes are particularly susceptible to blossom rot, also known as blossom end rot, though eggplant, squash and peppers may also be affected. Blossom rot is linked to calcium deficiency in the soil, high ammonia nitrogen content in the soil, uneven watering patterns and excessive application of fertilizer. Blossom rot has no specific cure, though steps may be taken to control and eliminate it if garden plants should develop the problem.
Things You'll Need
- Soil pH test kit
- Calcium or potassium nitrate fertilizer
- Calcium chloride foliar spray
Check the maturing fruits on garden plants each morning. Blossom rot may not be evident until the fruits appear close to full size. Blossom rot occurs on the blossom end or bottom of fruits, starting as a small, dime-sized brown spot. The spots feel dry to the touch and appear somewhat leathery.
Remove the affected fruits from the plant. Blossom rot leaves these fruits susceptible to fungal infection, which may result in damage to the entire plant.
Perform a pH test on the soil surrounding the affected plants using a commercially available test kit. Vegetables require a pH balance between 6 and 6.9, with 6.5 being ideal; this range indicates all nutrients should be available to the plants' root systems.
Add lime to the soil if the pH is below 6, indicating the soil is too acidic. The higher acid content blocks calcium uptake, resulting in blossom rot. Though this is not a cure for blossom rot, the addition of small amounts of lime may allow the plant to access appropriate amounts of calcium, thereby reducing the risk of further incidence to emerging fruits.
Review watering patterns. If the soil is consistently allowed to dry out, calcium availability is lessened. Keep the soil moist, but not wet. Monitor the plants closely after heavy rainfall, as too much water has the same effect; calcium becomes too difficult to access.
Follow manufacturer's directions carefully when using a commercial fertilizer. Use calcium or potassium nitrate fertilizer, rather than an ammonia nitrate, as ammonia blocks calcium uptake by plant roots. If using a homemade compost or compost tea for fertilizer, check the pH balance before applying to the soil. If the pH is too acidic, adjust by adding lime to the compost or tea.
Apply a foliar spray of calcium chloride to the plant, though the Cooperative Extension Service of the University of Georgia recommends that this be applied only to tomato plants. The foliar spray applies calcium directly to the plants, thereby providing a supply to aid in reducing the risk to subsequent fruits. However, the service also recommends soil treatments and appropriate watering practices be applied first, as these sprays may burn the plant, resulting in plant death.
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