-
- Articles
Index : Watering
-
-
- 15. Watering Potted Plants - Top
- As a rule, I say it's next to impossible to over-water potted patio plants in the summer, at least here in Tucson. But this isn't the case in the winter. When temperatures are cool, it is possible to over-water plants in pots, be they indoors or out. It is also possible to underwater houseplants, especially when the furnace is running; warming and drying the air.
So here are some general guidelines to follow in watering potted plants this winter.
Base your watering of outdoor potted plants on the weather. At temperatures of 70 F or lower, moisture loss through evaporation from the soil is very low. Also, when the weather is cool, most potted plants are not growing, and thus only require water to maintain moisture, not to produce new leaves and flowers. The exception to this would be cold weather flowers like pansies, violas, petunias, and cyclamen. They will continue growth with day-time highs in the 60's. Winter vegetables; broccoli, cauliflower, spinach, chard, will also grow at these temperatures. Watering of outdoor potted plants with temperatures in the 60's may only be required once or twice weekly. Just enough to keep the soil from drying out.
When temperatures are in the 70's, most annual flowers and vegetables will be growing and require more frequent irrigation. Even so, two or three times a week should suffice. Factors that will vary these recommendations include the size and type of pot, and the type of soil.
The larger the pot, the more soil, and the greater the water holding capacity. Given the same type of potting soil, large containers will not need watering as frequently as smaller ones. The smallest container size I recommend for patio plants is a 14 inch diameter pot. Smaller pots could be used in the Winter, but in the Summer they just can't hold enough water for plants to draw on in 100 + temperatures.
Potting soils also cause variations in watering. Some are very heavy in terms of both weight and density. What makes them so is a high percentage of what I refer to as bog peat. This is a highly decomposed form of peat moss that, when wet, holds water like a sponge. It's very easy to over-water plants set in potting soils comprised mostly of this ‘bog' peat. Lighter, better drained potting soils have significant amounts of perlite, bark chips, or shaghnum peat. These materials create larger open spaces in the soil, improve drainage and lessen the chances of over-watering.
Dense soils are even more of a problem for indoor plants. Because their not subjected to the heat that patio plants are, indoor plants are more likely to be over-watered. This is especially true in the warm months. In cool weather, heating the home can increase plant water requirements. However, it is still more likely that house plants will be over-watered than under-watered.
Indoors, I recommend the use of clay pots. Clay is porous and allows some evaporation of excess water out the sides of the pot. It's like a release valve for the build-up of excess moisture. But even with clay pots, if the soil is heavy and the watering too frequent, plants can become waterlogged and die.
Symptoms of over-watering can include the sudden death of a plant due to root rot. Or plants may decline gradually. This is first noticed as a stunting or lack of growth. The leaves are green and appear healthy, but there is little or no new growth. The next stage in the process is a yellowing and falling off of the lower leaves. Even at this point, if watering practices are corrected, it may be possible to salvage the plant. In the later stages, stems of some plants will become discolored and mushy or rotten. If this happens, it's too late! Throw the plant away and start over.
The easiest way to keep a handle on watering is to use a moisture meter. They can be purchased at most garden and hardware stores. The probe will push down in the pot 6 inches to test the moisture below the soil surface. If the plant you're growing requires even moisture, then water to keep the meter reading in the moist range. Potted cacti and succulents like to dry out between watering. Let the meter drop into the dry range before watering thoroughly. It's important that the soil not be kept moist. If it takes too long for the meter to move from wet to moist, then back off on the watering.
Written by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. - Updated: December 7, 2003
-
-
[e-Mail me
the Articles] - [Search
the Articles]
-
|
