Question
Up until this past week, my tomato plant has been doing great. Its about 5 feet tall and 2-3 feet wide, and has many tomatoes growing. Now several leaves are browning and looking unhealthy. About a month ago I removed two tomatoes because they were starting to rot on the bottom. I fertilize it with miracle grow all purpose feeders about once or twice a month. I have gotten a huge amount of rain this year, mostly in short lived down pours. What could this be? i have been removing the leaves to try and remove an mites or other pests.

Answer
Alexandra, the fruit on the plants are experiencing a non-fatal disease called blossom-end rot. This condition is caused by inconsistent watering and/or a lack of calcium in the soil. Based on your current weather description, your plants are experiencing the latter. The good news is that the symptoms will gradually disappear as this problem always corrects itself by late summer once the plants reach full maturity.  

When plants are watered too shallow, the roots reach for the surface causing stress and poor nutrient intake. By the same token, when plants are given too much water, the roots are deprived of oxygen and cannot absorb specific nutrients that are not as concentrated as others. Calcium is one of these nutrients. Most soils in the US are very low in calcium.

To counter this problem, you can add crushed eggshells to the soil or you can spray the plants with a solution of 1 tbs. of Epsom salts per gallon of water. Although Epsom salts are comprised primarily of magnesium, it has been proven that the plants will draw more calcium and other vital nutrients more efficiently when sprayed with Epsom salts. I add one or two tablespoons into each planting hole in the spring, and I seldom experience problems with blossom-end rot on either my tomatoes or peppers.  

Finally, when the weather does turn dry, make sure you water the soil deeply once or twice per week.  This will force the roots to grow deeper where lesser concentrated nutrients are more readily available. You should also mulch the plants heavily with dried grass clippings or straw to help retain moisture.  

I hope this answered your question. Please write again if I can ever be of assistance.  

Regards,  

Mike