Archive for Sunday, August 6, 2000

Seeing red?

Here’s some help for tomatoes that won’t go the distance.

August 6, 2000


Tomatoes are the most popular vegetable grown in home gardens. And this is the time of year when the tasty ripe fruit are best enjoyed. However, I have heard several gardeners complain that their tomatoes are slow to ripen. If your tomatoes are staying green, not setting new fruit, or the fruit is rotting on the vine, here are some possible causes and cures for the problems.

Ordinarily, tomatoes grow and ripen faster as temperatures increase. However, when daytime temperatures exceed 100 F and nighttime temperatures remain in the 80s, the ripening process slows down rather than increases. Pigments simply don't form when temperatures get too high. Lycopene is the cartotenoid that gives tomatoes their red color and it will not form if the temperature is constantly above 86 F. To hasten the ripening process, harvest the tomatoes when they show the first blush of red color and allow them to finish indoors.

Common belief is that nothing tastes better than a vine-ripened tomato. Taste tests, however, have shown that there is little noticeable difference between vine ripe and picked-early ripe tomatoes.

Another common problem is that new fruit is not "setting-on." Intense heat causes the female flower part (style) to grow past the anther (pollen bearing structure). Pollination doesn't take place and the flowers fall off. Next year try planting some of the new varieties that help combat this problem.

Finally, tomatoes can be injured by bright sun and high heat resulting in sun scald.

Sun scald starts as a light-yellow, leathery area on the tomato surface. Eventually the lesion turns brown and rots. Sun scald is worse in tomato vines with sparse foliage or in situations where wind has moved the foliage around suddenly. The weather this year has produced tomato vines that are fairly small and sparse while loaded with fruit prime conditions for sun-scalded tomatoes.

To help nurse the plants along give them a deep, thorough soaking every week or so to reduce water stress during this process. Likewise, mulch the soil surface to help minimize moisture loss and to help keep the soil as cool as possible.

To ensure you will have ample supply of tomatoes this year, keep your plants well fed and watered then be patient as Mother Nature will take care of the rest.

The Garden Calendar is sponsored by K-State Research and Extension-Douglas County office and written by Bruce Chladny, county extension agent,

horticulture. For more information call the Master Gardener Hotline, 843-7058, between 9 a.m. to noon and 1 p.m. to 4 p.m. Monday, Wednesday, or Friday.

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