Q:  My pots of tomatoes planted on my patio are forming a scab on the blossom end that is as large as the bottom of the tomato.  If the green part were dark brown it would look like a "buckeye".  What causes this?  B.R., Dallas.

A:  That’s blossom end rot and is prevented by having calcium available and watering properly. Water thoroughly and allow a drying period between waterings. Apply soft rock phosphate at about 3-4 lbs. per 100 sq ft. Spraying the foliage and drenching the soil with compost tea or Garrett Juice will also help.