Dial-a-Garden Message

for the Week of Monday, August 3, 2009

Susan Rose, Horticulture Education Specialist
Colorado State University Extension Tri River Area

Thank you for calling Dial-a-Garden. This message was recorded on Tuesday, August 4, 2009.

The evapotranspiration rate for the last week is approximately 1 ½ inches of water for Kentucky bluegrass in the Grand Valley. Precipitation has been variable, so please check your soil to determine your own moisture needs. If a probe (such as an old screwdriver) goes into the soil only a couple of inches, you’ll need to water. If it goes in six to eight inches, you can hold off for a few days.

Cut back on the frequency of watering to fruit trees and grape vines at this time, and don’t fertilize them any more this year. These plants need to begin the slow process of hardening off for the winter. Fertilizing and frequent watering stimulate more late growth, which may not harden off properly and will therefore be susceptible to winter injury, dehydration, and disease problems. Information about the process of acclimation for winter is available on our website at www.coopext.colostate.edu/TRA/PLANTS/winteracclimation.html or give us a call at 244-1836 to receive a copy.

Tomatoes that are not setting fruit may be suffering from high temperatures. Shading the plants helps, as does a layer of mulch and maintaining uniform moisture. They should make up for lost time once the daily high temperature is back in the low 90's. Blossom-end rot on tomatoes is another common problem this time of the year. Mulching the plants and keeping the soil uniformly moist helps. Tomatoes do not need a great deal of water, but they do need fairly even moisture in the soil to prevent this common situation from developing. If your tomatoes are in pots, provide some shade for the hottest part of the day and keep an eye on the moisture; you may need to water daily or even twice daily. If you do get blossom-end rot, just cut away the blackened portion of the fruit; the rest is fine to eat.

Another symptom of problems with tomatoes may be yellowing leaves. If the lower, older leaves are yellowing, the problem could be insufficient nitrogen. Tomatoes do fairly well on frequent, light doses of this nutrient, so give it a try. You may use a product that is mixed and applied as a liquid, or a granular product that will need to be watered in. If the leaves all over the plant turn a pale bronzy yellow, spider mites may be the problem. Try an insecticidal soap, testing first on a small area and waiting a day or two to be sure the soap isn’t doing further damage to the plant. The soaps are contact only, and since the mites are mainly on the undersides of the leaves it will take a little effort to reach them. More on spider mite controls may be found at http://www.ext.colostate.edu/pubs/insect/05507.html and you can bring us in a sample if you want to be certain. Most people can’t see spider mites without a microscope or at least a hand lens.

When squash, melons or cucumbers have fruit that rots before maturing, it may indicate a lack of pollinators. The female flowers of these plants require multiple visits from the pollinators in order to set fruit, and the flowers are only open for a single day. Also, male and female flowers must be open on the same day, which can be a problem if you have only one or two plants. The female flowers, which have immature fruits beneath them, can be manually pollinated by transferring pollen from the male flowers, which are on slender stalks. Collect the pollen with a swab or soft brush, and twirl it gently on the stigma of the female. If you have more than one plant, transfer the pollen from a different plant for best results. Visit our website at www.westernslopevegetables.org for more information on solving vegetable garden problems.

If you are having the problem of excess fruit or vegetables, drop that excess off at the Mesa County Extension office where Grow Another Row volunteers will collect them on Mondays and Thursdays. The fresh produce is then distributed to area food banks, and is very much appreciated. The Extension office is located on the fairgrounds.

Give us a call or drop by if you are having yard or garden problems. Our offices are open Monday through Friday, except for major holidays. We’re open 8:00 to 5:00, though we do occasionally have to close for lunch; please call ahead if you are planning to visit between noon and 2:00 p.m. In Montrose, we’re at 1001 North 2nd Street in Friendship Hall; the number there is 249-3935. In Delta we are located at 525 Dodge Street, across the street from the courthouse; that number is 874-2195. In Grand Junction, we are located on the Mesa County fairgrounds at 2775 Highway 50, and our number is 244-1836.

Thank you for calling Dial-a-Garden. This message will be updated next week; have a great week!