-
- Articles
Index : Watering
-
-
- 15. Get Ready to Collect Summer Rains - Top
- Summer rains have special properties beneficial to plants. Electrical charges released during our Monsoon thunderstorms combine atmospheric nitrogen (N2) with hydrogen (H2) or oxygen (O2) to produce nitrate (NO 3) or ammonium (NH4). Both nitrate and ammonium are forms of nitrogen commonly contained in fertilizers, and easily taken up by plant roots. That's why everything really does look greener after a thunderstorm!
In addition to nitrogen, rain brings other plant beneficial substances. Dust carried on the jet stream, sometimes from as far away as Africa, contains a number of beneficial mineral nutrients and micro-organisms. But best of all, rainwater is free of salts and chemicals that can be harmful to plants.
Now at the start of the Monsoon season is an excellent time to make preparations to utilize as much rainwater as possible for your container plants, garden and landscape. It will be necessary to trap and store the water for use as needed. The easiest way to store water is in plastic trash barrels. Specially designed rain barrels made of plastic and wood may also be purchased from speciality suppliers over the internet.
Rainwater is easiest to collect off the roof, but this requires a guttering system and a down spout or down spouts to direct the water into the rain barrels. The cost of a guttering and down spout system for a 2,000 square feet home will run around $250, less for a partial system. For every inch of rainfall, you can expect to collect .6 gallons of rainwater for each square foot of roof area. For a 2,000 square foot home that would equate to 1,200 gallons of water. With 6 inches of rainfall over an average Monsoon season, you have the potential to collect 7,200 gallons of water. That's a lot of rain barrels!
There are ways to store large amounts of water. Rain barrels may be connected in a series with PVC piping to provide more storage capacity. Some gardeners in Tucson use large underground storage tanks, others utilize stock tanks above ground to hold hundreds of gallons of water to use as-needed. Stock tanks in various sizes can be obtained at our area feed stores. All above ground storage containers must be covered to avoid algae growth and the breeding of mosquitos.
If you can catch only a limited amount of rainwater, probably the best use for it is to water your container plants. Indoor plants are most appreciative of pure water, free from salts and chemicals. Next comes potted plants growing on your patio. If you have water left over, use it for your flower or vegetable garden.
Another way to harness rains that doesn't involve collection and storage is through rainwater diversion. Summer downpours can run off your property and into the streets and washes in a flash unless you plan some diversions to direct the flow of water to plants.
During a heavy rain, put on your poncho, and go out to observe how water runs through and off you property. Think of ways to slow or divert the flow to allow it to be absorbed into the soil. Terracing of soil or building small rock dams can work for this purpose. You can also redirect the flow of water by fashioning small channels or swales through the landscape to where the water is most needed for plants.
Many back yards of urban properties are bordered by privacy walls. These walls have openings at the base to allow water to drain out. Partially blocking the openings can hold in rainwater, giving it a chance to soak into the ground. Leave a gap at the top, so any excess water can flow out the openings before it gets high enough to back up into your home.
When planting new trees, shrubs or ground covers, consider shaping wide, shallow ‘dish-shaped' depressions in the soil so that plants are located in the center of these depressions. Rainwater will collect there, giving extra water to the plants within. For low-growing pants a 2 inch deep depression sufficient. Trees and shrubs, with their deeper roots, will require a slightly deeper 3 inch depression. The width of the depression should also correspond to the plant size. Trees will need an area as wide as the canopy spread to capture sufficient amounts of water.
If your landscape is on a slope, instead of basins, berms can be created on the down-slope side of trees or shrub groupings to prevent water from flowing away.
Finally, if your considering installing a lawn, grade the area to resemble a dinner plate, with a gentle concave shape. This will help prevent irrigation water from running off the area and allow rainwater from surrounding areas to flow in.
Written by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161.
- Updated: June 29, 2003
-
-
[e-Mail me
the Articles] - [Search
the Articles]
-
|
