What is Internal Tipburn?
Problems with vegetables caused by cultural and environmental situations are common. Even professional growers may be beset by nutritional deficiencies, irrigation issues, or even excess fertilization which causes damage to their crops. In the case of internal tipburn, any one of these can cause the situation. Internal tipburn in cole vegetables can be managed, however, and is considered a moderate crop plant concern. The initial signs of internal tipburn in cole vegetables are at the center of the head. Tissue breaks down and, in the case of cabbages, turns brown and papery. The issue resembles a type of rot but is not associated with any fungal diseases. Over time, the entire head becomes dark brown or black, allowing bacteria to enter and finish the work. The issue seems to begin as the vegetable enters maturity and does not affect young plants. Whether internal tipburn is cultural or nutrient based is a matter of debate. Most experts believe it is a combination of environmental and nutrient problems. The disorder resembles what happens in blossom end rot or blackheart of celery.
What Causes Cole Crop Internal Tipburn?
Internal tipburn of cole crops appears to be the result of several factors. First, its resemblance to several other common vegetable diseases seems to point to a lack of calcium in soil. Calcium directs formation of cell walls. Where calcium is low or simply unavailable, cells break down. When there is an excess of soluble salts, calcium that is available cannot be taken up by roots. Another possibility for internal tipburn of cole crops is irregular moisture and excessive transpiration. This leads to rapid water loss in the plant in high ambient temperatures and a failure of the plant to uptake soil moisture. Rapid plant growth, excessive fertilization, improper irrigation, and plant spacing are also contributing factors to cole crop internal tipburn.
Saving Cole Crops with Internal Tipburn
Cole crop internal tipburn can be difficult to prevent due to the inability to control all environmental factors. Reduction of fertilizing does help but commercial growers are interested in yields and will continue to feed plants. The addition of calcium does not seem to help but increasing moisture during excessively dry periods seems to have some success. There are some newer varieties of cole crops which seem to be resistant to the disorder and trials are under way for more resistant cultivars. In the home garden, it is usually easily managed. If it does occur, harvest the vegetable early and simply cut out the affected part. The vegetable will still be delicious once the affected material is removed.
