Paula asks: I just picked my first tomato this year and was really disappointed to see that it had a hard dark brown area on the bottom and the tomato was soft and mushy. What’s going on?
Tropical Gardener answer: It sounds like you have blossom end rot on your tomato. This is a symptom of a lack of calcium getting to the plant. BER can affect all or a few of your tomatoes and can sometimes become severe with a black area developing over the bottom half of the fruit.
The problem is usually caused by insufficient calcium in the soil or by soil water fluctuations or by an oversupply of nitrogen in the soil. Adding about ½ cup per plant of a calcium product like gypsum (calcium sulfate) or lime (calcium carbonate) to the soil before planting may help prevent this problem in the future. If the plant’s water supply fluctuates, its calcium supply will also fluctuate. Mulching can help maintain consistent soil moisture. Avoid over-fertilizing with nitrogen as it encourages a rapid growth rate which may increase the plant’s calcium uptake in the process.
Twice weekly foliar sprays of calcium chloride or calcium nitrate at the rate of four tablespoons per gallon of water may prevent the problem on fruit that is now developing but this will not replace soil calcium and can be toxic to plants at high concentrations. Stabilizing the moisture level in the plant’s soil can also help.
You could also try some of the anecdotal recommendations for preventing blossom end rot from affecting the developing fruit. Soil applications of powdered milk or crushed Tums tablets and foliar sprays of teas made from bone meal or crushed egg shell have helped other growers. Try them if you like.
For more information on blossom end rot in Hawaii download the UH free publication: http://www.ctahr.hawaii.edu/oc/freepubs/pdf/PD-85.pdf
Some questions that appear here were originally directed to Kona’s Certified Master Gardeners.You may contact them with questions at konamg@ctahr.hawaii.edu.
Diana Duff is a plant adviser, educator and consultant living on an organic farm in Captain Cook.
Gardening Events
Saturday: “Work Day at Amy Greenwell Garden,” 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center in Captain Cook. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Call Peter at 323-3318 for more information.
“Edible Landscaping,” 9 a.m. to 3 p.m. at Hawaii Community College-Palamanui with Zach Mermel. Cost is $55. For more information or to register, call 974-7664 or visit www.hilo.hawaii.edu/academics/ccecs/EdibleLandscaping.php.
Farmer Direct Markets
Wednesday: “Hooulu Farmers Market,” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay
“Sunset Farmers Market,” 2 p.m. to sunset at the Kmart parking lot.
Saturday: “Keauhou Farmers Market,” 8 a.m. to noon at Keauhou Shopping Center.
“Kamuela Farmer’s Market,” 7 a.m. to noon at Pukalani Stables.
Sunday: “South Kona Green Market,” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook.
Monday through Saturday: “U-Pick greens and produce,” 10a.m. to 4 p.m. at Tropical Edibles Nursery in Captain Cook.
Plant Advice Lines
Anytime: konamg@ctahr.hawaii.edu
Thursdays: 9 a.m. to noon at UH-CES in Kainaliu, 322-4892
Monday, Tuesday and Friday: 9 a.m. to noon at UH-CES at Komohana in Hilo, 981-5199 or himga@hawaii.edu.