“BLOSSOM END ROT” is a very common problem that can be prevented.  The major cause is lack of calcium going to the fruit because of moisture stress and/or over fertilization. Calcium dissolves in water and moves through the plant in the vascular system.  Under moisture stress from irregular watering, the calcium goes to the leaves and stems and thus is deficient in the fruit, causing blossom end rot. It can occur even in gardens where there is abundant calcium in the soil. Most gardens in Southeast and South Central Nebraska have sufficient calcium in the soil and additional applications, either to the soil or on the leaves (foliar), does not help stop the problem. Blossom end rot in tomatoes usually occurs on the first fruits of the season and may be seen on other fruits and vegetables such as watermelon, squash, peppers, and eggplants. Rapid plant growth from over fertilization with nitrogen, and moisture stress from irregular watering are the two major causes why calcium does not go to the fruit. Blossom end rot is not a disease but what we call an abiotic problem. That is, it is caused by a physiological disorder.           

          In summary:

1. To prevent blossom end rot and other plant diseases---“DO NOT OVER FERTILIZE!!!” Also, if you have too much nitrogen in relation to phosphorous, you may have beautiful big tomato plants but very few tomatoes. Nitrogen makes your foliage grow, and phosphorous is good for flowering and fruiting.

2. The major cause of Blossom End Rot is irregular watering, especially during periods of fruit set, fruit development, and rapid plant growth. Tomatoes need at least 1 inch of water per week during hot windy weather. One watering per week of one inch is better than one-half inch of water applied twice a week according to one source. The important thing is maintaining uniformly adequate soil moisture throughout the season.  

3. The third way to prevent not only blossom end rot but tomato blight is through the use of mulch.  Mulch can be straw, dry grass clippings, leaf clippings that have been run through a mower, compost, or 6 to 8 pages of newspaper. I spread out newspapers, 6 to 8 pages deep between my tomato cages and then put straw, compost or soil over the top to hold them down. This mulch helps to conserve moisture and prevent the soil from drying out rapidly. Mulch also helps prevent the disease pathogens that are in the soil from splashing up onto the lower leaves.

4. To prevent diseases in your tomato plants do not water overhead with a sprinkler. I put a soaker hose under the newspapers or mulch. If you have to overhead water, do not water after 2:00 pm in the afternoon. Many disease pathogens are in the soil, and in the air. A drop of water on the leaf most of the evening helps the pathogen inoculate the leaf that spreads to the rest of the plant. Therefore, water early so the plant leaf is dry going into the evening. You can’t prevent the rain, but you can decrease the amount of disease by good watering practices. And, as mentioned above, mulch helps prevent disease pathogens from splashing up onto the leaf. Some pathogens are vectored (transmitted) by insects such as cucumber blight.

5. Purchase disease resistant varieties. When you go to the Garden Center and purchase tomato plants, do you pay attention to all the information on the tag? Do you know what all those letters and words mean? Some of the strange words and letters on the tag include:

·        VFNT: A plant tag may have one letter, two letters, or all four letters. These letters are not college degrees but do indicate disease organisms that hybrid tomatoes have been bred to resist. The V stands for Verticilium Wilt; the F means the plant is resistant to Fusarium Wilt; the N stands for nematode resistance; and the T for Tobacco Mosaic resistance. Remember, they are disease resistant not disease proof.

·        DETERMINATE AND INDETERMINATE: Determinate tomato plants are usually shorter and do very well in containers. The major characteristic of determinate varieties is the fact that they usually have a big flush of fruit and then a few fruit the rest of the season. If you like to can or freeze most of your tomatoes all at once, then look for determinate varieties. Indeterminate varieties of tomatoes start setting on fruit and they continue until frost. These varieties are usually taller and need to be staked or contained in a cage

6. Don’t plant tomatoes too early. Soil temperature, not air temperature is the major consideration. If the soil temperature is too cold, the plants will just sit, and if it is rainy, may start to rot. You may get early blooms or even small tomatoes on the early plant, but if the evening temperatures consistently get below 55 degrees F. the bloom will have a harder time pollinating and the tomatoes will not change color.

7. Grow your plants in good cages. I made my own cages from concrete reinforcing fence. The fencing comes five feet tall and I cut pieces about five to six feet long and bend them into a circle. These have lasted me for years. My plants get very tall so I pound pieces of rebar about 5 feet long into the ground to support the cages so our strong Nebraska winds does not blow the plants and cages over.

8. Plant deep.  Tomatoes can be planted very deep and the hairs on the stem will develop roots. I strip all but the top few leaves off my transplants and then put the plant so they are just above the soil line.

9. The last tip is to be sure and prune. When my tomatoes are about 3 feet to 4

feet tall, I trim off the lower 8 inches to 10 inches of stems and leaves. This allows for good air flow up through the plants and helps to prevent disease. In addition you may need to go in during the months of June and July and do some pruning. Don’t be afraid to prune and thin out your plant so you have good air flow and large juicy tomatoes. Cutting off those stems is hard for me to do, especially when they have blooms or even small tomatoes. But I know it is good for the plant. As I mentioned many pathogens need a drop of water on the leaf and if you do not have good circulation, the leaf will not dry off. Also, make sure you do not plant your tomatoes too close together. Powdery mildew, leaf blight, and other diseases love damp wet conditions when there is poor air flow. Plants need good air circulation between the plants and up through the plant.

          If you get a good abundant crop, as I usually do, please share with the Food Bank, or some other food distribution group. Or start a “Harvest Table for Missions” at your house of worship. Go the second mile and put in one or two extra plants just for sharing with an elderly neighbor, the Food Bank, or your Mission Table.

Copyright 2012