My question is: Why do Early Girl tomato plants split? Last summer, I had them in large pots, watered once a day, sometimes every other day. They had no pests on them and I used fertilizer for tomatoes.

– Pat Tornberg, Rancho Murieta

According to UC master gardener Carol Rogala, tomato fruit cracks (and "cat-facing") can be circular cracks around the stem end of the fruit, cracks radiating outward from the stem or malformation and cracking at the blossom end.

There are several causes for this problem:

• Periods of very fast growth with high temperatures and high soil moisture levels.

• Wide fluctuations in soil moisture content or heavy rain following a dry period.

• Wide differences in day and night temperatures.

• Any disturbance to the flower parts during blossoming.

• Some varieties are more susceptible to cracks and cat-facing than others.

To help control these issues:

• Choose varieties that are adapted to your climate zone and are less susceptible to cracking.

• Keep soil evenly moist.

• Maintain good leaf cover or provide partial shade in periods of high light intensity.

• A layer of organic mulch 3 to 4 inches deep such as compost helps moderate soil temperatures and soil moisture fluctuations.

• Healthy, vigorous transplants should not require fertilizer until flowering and fruit set are well under way. Be sure to read the directions and apply fertilizer correctly.

• Plants in pots may require more frequent watering than plants in the ground. However, stick your finger in the soil to see if it is moist before you water.

• The cracking does not destroy the fruit and it is still edible.

GARDEN QUESTIONS?

Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties. Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to h&g@sacbee.com. Please put "Garden Detective" in the subject field and include your postal address. To contact your UC Extension directly, call:

• Sacramento: (916) 875-6913; 9 a.m.-noon and 1-4 p.m. weekdays

• Amador: (209) 223-6838; 10 a.m.-noon Monday through Thursday; email ceamador.ucdavis.edu

• Butte: (530) 538-7201; 8 a.m.-noon and 1-5 p.m. weekdays

• El Dorado: (530) 621-5512; 9 a.m.-noon weekdays

• Placer: (530) 889-7388; 9 a.m.-noon on Tuesdays, Wednesday and Thursdays or leave a message and calls will be returned

• Nevada: (530) 273-0919; 9 a.m.-noon Tuesdays through Thursday or leave a message

• Shasta, Tehama, Trinity: (530) 225-4605

• Solano: (707) 784-1322; leave a message and calls will be returned

• Sutter, Yuba: (530) 822-7515; 9 a.m.-noon Mondays and Tuesdays and 1-4 p.m. Thursdays

• Yolo: (530) 666-8737; 9-11 a.m. Tuesdays and Fridays, or leave a message and calls will be returned

© Copyright The Sacramento Bee. All rights reserved.

Order Reprint