Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your question about no fruit but lots of flowers on your tomato plants
There could be several reasons for lack of fruiting in tomatoes:
-- Night temperatures too low, below 55ºF (12.8ºC);
-- Daytime temperatures too high, above 90ºF (32.2ºC).
The plants will produce when temperatures become favorable. Note, though, that heirloom tomatoes can be fussier about temperatures than most hybrid tomatoes and in some areas can wait until late summer or early fall to start setting fruit.
-- Excess nitrogen fertilizer. Lots of healthy green leaves and stem growth, but few flowers or fruit.
-- Too much shade – you need a minimum of six hours of sun to produce fruit.
-- Lack of pollination. While tomatoes are self-fertile, the conditions mentioned above will inhibit pollination.
-- Plants set out too early in spring. -- We recommend planting tomato seedlings the first of May; often earlier planting of seedlings will be inhibited by cold temps and they will just “sulk”; consistent warmer weather and nights should get them growing
-- Choose varieties adapted to your climate zone,
-- Plant tomatoes in full sun,
-- Keep soil evenly moist,
-- Avoid excessive nitrogen fertilizer, and
-- Tapping on blossom stems 3 times a week at midday when flowers are open may improve pollination and help set fruit.
Here is a comprehensive UC link about tomato culture, pests, diseases, and environmental disorders: http://ipm.ucanr.edu/PMG/GARDEN/VEGES/tomato.html
We hope this information helps! Let us know if you have any additional questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (SLH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone: (925)646-6586, email: firstname.lastname@example.org, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/)