Gardening Tips: July 24, 2013

Heat Stress
We have had above average temperatures for more than the past 30 days now and this heat wave shows no sign of abating. I suppose if I dragged my air conditioner out of the back room and hooked it up in my bedroom, the heat wave would go away, but so far it has been cool enough at night to sleep at least. Working outside in the garden is not pleasant in this weather and I would caution all of you to be very careful if you have to do so. Heat stroke is deadly serious and does not require all that much exertion. Drink lots of water, even if you do not think you are thirsty.
Gardens are growing amazingly fast as both heat and moisture have been more than adequate. Some areas however, such as the Northern Catskills are actually in need of rain right now. Plants pump huge quantities of moisture into the atmosphere as they try to keep cool. The roots absorb water that exits as water vapor through tiny pores on the undersides of the leaves called stomates. It does not take long for soils to dry out when the plants growing on them are pumping out thousands of gallons of water per acre per day. I have noticed that even the creeks are getting low again after flooding just a few weeks ago.

Garden problems
Unfortunately, along with the heat and humidity comes diseases or all sorts on our precious garden plants. I have observed early blight on my tomatoes already. Early blight begins with small, yellow colored, target like or bull’s eye, spots on the lower leaves. Soon after infection the leaves turn entirely yellow, then brown and eventually they shrivel up and die. This disease can progress very rapidly up the plant and within a few weeks most of the foliage can be gone. Without all those green leaves manufacturing sugars, the ripening fruit will not develop the taste we desire. Green tomatoes exposed to full sun due to defoliation may also develop hard, white areas on the skin, appropriately called sunburn. Early blight, like all garden diseases, cannot be “cured” once the tissue is infected. If you apply a protective fungicide, it will only help to prevent the disease from spreading. It also helps to remove infected leaves to reduce the number of infectious spores produced. I sprayed my plants this week with “Funginol” to try to contain the infection. Last week or perhaps the week before, I discussed blossom end rot. This disorder is not a disease, but it looks like the bottom of the fruit is rotting with a black area. It is caused by inadequate uptake of calcium which in turn is caused by the root system not being able to supply enough calcium. It usually only effects the first fruit to ripen. As the plants develop adequate root systems, it cures itself.
If you have not mowed your lawn recently, do not mow it now! Tall lawn grass is far more drought resistant than short mowed grass. Soil temperatures are well into the 80s now and there is no root growth occurring at these temperatures. Cutting the grass blades puts extra stress on them at a time they are already stressed by the heat.

Use moderation
I realize that it seems only logical to water the gardens much more during this hot spell but be careful not to overdo it. Many garden plants will wilt in this heat in mid afternoon regardless of how much water you apply and it is possible to drown the roots. Shallow watering with a sprinkler also discourages deeper root growth. Newly planted trees and shrubs need only about an inch of water a week and well-established ones ( three years or more in the ground) almost never need watering. Put a shallow saucer near your sprinkler and see how long it takes to record an inch and adjust your practices accordingly.
If possible, water early in the morning so the foliage dries out quickly. This will help to reduce disease pressure also. Most garden diseases are also quite specific as to what hosts they attack. The blight that may be affecting your tomatoes is not the same blight that is on your apples or pears. Each disease needs to be diagnosed individually and treated appropriately. Read and follow all label directions when using any sorts of pesticides, as difficult as this is to do, or have someone who is knowledgeable explain to you exactly how to use the product. Using the wrong product on a food plant may prohibit you from eating the vegetable you have worked so hard to grow.