A word about watering

Wednesday, June 8, 2005

May was one of the driest months on record. I just heard the weather forecast for the next week, and the prospects of rain don't seem very good.

Because of the lack of moisture gardeners are bringing out their hoses and sprinklers. The boring task of watering is about to begin.

The lack of moisture has also increased the number of questions that I have fielded about watering. Therefore I am covering Watering 101 in this column.

When you do water, water thoroughly. Don't ever water "lightly." Fill all of the pores in the soil where your plants are rooted. If your plants are in soil, then water until all of the soil around the plant is mushy. If your plants are in containers, water until excess water pours out of the drainage holes.

When watering keep water off plant foliage, if possible, by watering underneath the plant. Free water on plant foliage increases relative humidity around the plant and creates conditions favorable for plant disease development.

If your hose has been sitting in the sun for a while, the water in the hose may be so hot that the foliage may be scalded. Make sure that you use cool water.

If at all possible, water in the early morning. Watering during the heat of the day may result in scalded foliage of succulent plants. If you water in the evening, plant foliage will have lots of free water standing on it all night long. Again, this condition is favorable for developing plant disease.

Watering frequency will be determined by a host of conditions. Higher wind speeds, more sunlight and higher temperatures will increase a plant's water usage. Soil types also determine water availability to plants rooted in soil.

In addition, if your plants are in containers other factors will also influence watering frequency. Pot size, pot size relative to plant head size, root density and soil density also determine water needs.

I often hear people say that they have an automatic watering system, so they won't have any water problems. Quite often these are the people that have the most problems with watering. There is nothing wrong with the system, but people have to tell the system when and how much to water. If you give the system the wrong directions, your plants will suffer.

Because of all the variables listed above, there is no formula available to determine how often to water. Therefore I recommend that you stick your finger in the soil around the plant you want to water. If the soil is wet, don't water it. If the soil is dry, give it a good drink.

I also want to remind you that new plantings should be treated the same way. Don't use a formula and water every day or every other day just because you just transplanted the shrubs in your landscape. Always use the finger test to determine when to water.

The basics of watering are the same for container gardens as they are for plants rooted in the ground. Unfortunately there is less room for error when watering plants in containers. The roots of container plants are confined. If you forget to water them, they can't continue to grow and seek out water in other areas of the soil.

Quite often a gardener says that he waits to water until his plants are drooping. This indicates to him that water is needed. Unfortunately when plants have been over-watered for a long period of time, they often droop in the hot afternoon. They droop because their diseased roots are not working properly. If you water when plants are drooping, you may be continually over watering, and making your problem worse.

The forecast over the next few days indicate that rain will not be forthcoming. Therefore keep an eye on the plants in your landscape. But only let the moisture condition of the soil tell you when to water.

Send your gardening and landscape questions to Paul Schnare at P.O. Box 699; Cape Girardeau, Mo. 63702-0699 or by e-mail to news@semissourian.com.

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