City water is expensive so let’s use it with as little waste as possible. This can be done with a little careful observation on the part of the gardener. One of the first things a beginning gardener learns is that shallow watering produces shallow roots. Roots develop and grow only in moist soil that has good air circulation and nutrients.
This means that the gardener should have some knowledge of the amount of water the various plants he grows need to do their best. A rose-growing friend discussed the water needs of roses with another rose grower that had exceptionally fine plants. The second grower stated that he gave each of his plants two gallons of water a week, starting in spring when the rains tapered off. My friend planned to do the same thing so he checked the time it took his hose to fill a two-gallon pail then proceeded to let the hose run at each plant for that length of time, then waited a week before the nest application. It didn’t work out as my friend forgot his informant had a clay base soil while he lived in the sandy soil area of San Francisco.
The best way to work out a program is by a series of tests. A soil test tube will more than pay for itself in one season. Use it each time you water for two or three weeks and use it again each day after watering to test for soil penetration and for soil moisture during the after watering period. The soil test tubes are about one inch in diameter and approximately twenty inches long. A portion of the tube is cut away so that when the tube is pulled from the soil the gardener has a complete profile of the soil showing the depth of penetration and the moisture content.
The tubes are adequate in length for most everything we grow except trees. Tree roots, on many varieties, go down several feet but usually, if we keep the top two or three feet of soil moist from the time the rains stop, the roots will have adequate water.
3 Types of Soil
For practical purposes, the soils in our area are divided into three classes: clay and adobe, loam, then sand. Soil scientists have discovered that one inch of water will penetrate about 12 inches of sand, six to ten inches of loam and only four to five inches of clay or adobe. This is because the clay and adobe are made up of such fine soil particles. The addition of humus material to clay and adobe soils separate the soil particles and permit the water same token the addition of humus material will slow down the loss of moisture in sandy soil thus stretching the period between watering.
Most gardeners wish to encourage deep rooting and I am often asked how much water do we need to apply to get deep roots. Sunset’s new Garden Book has answered this question. Their writers researched the watering problem and found that if you wish to soak a 100-square-foot of soil to a depth of two feet, you would need 125 gallons of water for sandy soil. 190 gallons for a loamy soil and 330 gallons for clay. They also found that if you apply the water with a hose under normal volume of about five gallons a minute it would take 25 minutes to soak the sandy soil, 38 minutes for the loam and an hour and five minutes for clay.
Actually it would take longer far clay as it can’t take up water at the rate of five gallons a minute. You would have run-off that would waste the water. I use an oscillating sprinkler to water my hillside as I can put the water on slowly enough to prevent run-off. I placed coffee cans, the one pound size, at two foot intervals in a line up the hill from where I placed the sprinkler. This gave me a rather accurate idea of the time it took to apply an inch of water on an average low-wind day. I found that my planting in one section required the sprinkler hat to run two hours to satisfy the needs of my plants. I sued the soil test tube to find out the depth of penetration. Now I just place the sprinkler in a marked spot, turn it on and set the timer.
Timers Save Worry
If you have to leave at any given time, one of the available timers can be attached to the faucet that will shut the water off when the time is up. When I think of the many times I rushed out of the house to keep an appointment, leaving the water running in some section of the garden, I know that I could have paid for several of these timers. Lawns take more watering than possibly any other type of planting. It also takes more knowledge of the needs of the various grasses to do a good job.
Husbands, or wives, that like to spend a little time after dinner waving a hose over their lawns are relaxing, not watering the lawn. If they do this every evening in hot weather they are inviting trouble. Grasses like to be watered deeply then be left alone until the grass is near the wilting stage. You can tell when your lawn needs water by using your soil test tube and checking the moisture content of the soil. Or when you look out the window and find the grass looks tired it is most likely too dry. Walk across the lawn and a well fed, well watered grass will spring upright as soon as your foot is lifted but if the soil about the roots is dry the grass blades will be slow about straightening up.
Compacted soil in a lawn area is difficult to wet. It is also difficult to keep an adequate supply of humus material in the soil under a lawn as we can’t dig it up, like we can flowers, and remake the soil. My only recourse is to aerate the soil by making holes through the turf. A friend did this with a pitchfork last week then raked sand into the holes. This is slow work and far from satisfactory as the holes made by the tines of a pitch fork are small and they only compact the soil tighter between holes. It is better to hire the holes made by a machine that will lift out a core half an inch in diameter and about five inches in length. These holes are easily filled with sand or fine bark so the water can penetrate easily. The open holes are an excellent way to get humus into the soil beneath the turf.
http://gardening.wsu.edu/library/lanb002/lanb002.htm
