Blossom End Rot
The first symptom of blossom end rot in tomatoes is the appearance of what looks like a watersoaked area at the bottom of the fruit. This area continues to deteriorate, turning black or brown and shriveling, leaving a leathery sunken area. The culprit? A lack of calcium. This does not necessarily mean the soil is deficient in calcium; it may simply mean that the plant cannot take up the calcium, which could be a result of several factors:
• A lack of steady moisture during periods of drought; always keep tomatoes moist, especially when the fruits are setting and developing.
• Rapidly growing plants; fast growth requires an abundant supply of water and calcium. Excess nitrogen can contribute to the problem by speeding up growth.
• Transplanting tomatoes into cold soil, causing the organisms that convert calcium into a usable form to be less active.
• Cultivating deeply around tomatoes, damaging roots and causing a lack of water and calcium uptake.
Try these tips to avoid blossom end rot:
• Soil should be moist but not sopping wet. Excess water is just as bad as not enough.
• Mulching will help maintain even soil moisture.
• Shallow, frequent cultivation is best.
• Adequate but not excessive nitrogen.
Common Scab
Have you ever started harvesting your potatoes and noticed scab-like growths on the skins? Common scab is a disease of bacterial origin. The symptoms may include tan to dark brown, rough-textured lesions on the tuber surface. The extent of the lesions depends on the extent of the disease. Scab is usually brought into the soil by infected tubers and will survive indefinitely in the soil. Common scab is most severe in warm, quick-drying soils and increases through a pH range of 5.2 to 8.0.
Scab is more of a cosmetic disease. It does not affect production, only the appearance of the potatoes. While it is possible to adjust the soil pH to inhibit the disease, altering the pH could also change the optimum growing conditions for the potatoes and affect yields.
While eliminating scab is very difficult, you can reduce its occurrence and severity:
• Try to plant scab-free tubers or seeds.
• Rotate the crops in the affected area, keeping three to four years between potato crops.
• Keep the potatoes well-watered during the formation of the tubers( four to six weeks after planting).
• Plant varieties that are more resistant to scab, such as Norland( red) and Kennebec( white).
Gerald Filipski— Jerry, more commonly— has been the gardening columnist for the Edmonton Journal for over thirty-five years and has appeared in the Calgary Herald and other
Canadian publications. Jerry has also authored Just Ask Jerry: Good Answers to Tough Canadian Gardening Questions.
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