Watering Your Lawn

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132. When is the best time of day to water a lawn?

The best time is early in the morning when the wind is calm and the grass is already wet with dew. Usually the water pressure will be higher in the morning. Remember that keeping the grass wet for long periods of time during hot weather incubates diseases.

While morning watering is the best time slot for seeing to your lawn’s needs, you should be aware that watering can be done any time. In some cities and states, laws dictate the time of day you can water your lawn.

133. How can I tell when my lawn needs water?

The best way is to test the soil for moisture with your fingers. If the soil is dry three inches to four inches deep, then it is time to water. Another way is to keep an eye on the grass and when it shows a bluish color (wilting) or has lost its normal green color, then it is time to water.

134. How often should I water my lawn?

This is determined by the variety of grass, soil conditions, and the weather. It is best to wait until the soil has dried two inches to six inches deep; then apply enough water to soak the soil again to this depth. Watering every day is a poor practice because it favors weed growth and encourages the grass to be shallow-rooted and weak.

135. Does the type of soil in my lawn affect the watering schedule? Yes, because the soil acts as a natural reservoir. The more clay present, the greater the water-holding capacity of a soil. A sandy soil will hold less water in the root zone. Organic matter holds large quantities of water; therefore the amount present in the soil will also influence how often you have to water a lawn. (See Table 5—1.)

TABLE 5-1 Approximate Water-Holding Capacity of Soils

Soil type

Inches of water per foot of soil depth

Sandy soils

Loam soil

Clay loam soils

Clay soils

3/4 to 1

1 to 1-1/2


2 to 2-1/2

136. How much water will grass remove from the soil in a day?

This will vary depending on the type of grass, soil condition, and weather. It can generally be said that grass will remove about one-fourth inch to one-half inch of water from the soil on a hot day.

137. Is liquid fertilizer a substitute for water?

Fertilizers should not be considered a substitute for water. The grass plant needs water regardless of the amount of fertilizer applied. Ample watering helps to dissolve the fertilizer so that its nutrients can be more easily used by the grass plant. Fertilizers are important in the greenness and rooting of the grass.

Rainfall Doubles As a Fertilizer

Rainfall is beneficial to lawns in more ways than just supplying moisture for plant growth. If you live in an area with o inches of rainfall per year, the rain will contribute up to 6% pounds of nitrogen per acre. This nitrogen will be sufficient to replace any lost from the soil due to leaching.

138. Does watering during the heat of the day hurt the grass?

No. It is often very beneficial when done on extremely hot days. Watering will cool the surface temperature of the soil and will also reduce the heat stress on the grass.

139. Will the grass green-up again after it has turned brown during long, hot, dry spells in the summer?

Grass will go dormant three to five days after the first signs of its wilting. Once it has gone dormant, the addition of water will allow the grass to green-up again, but the recovery is usually very slow.

140. Is the grass harmed by letting it go dormant?

The mechanism that causes the grass to go dormant is nature’s way of protecting the grass during periods of stress. The grass will recover completely, but during this recovery period, the weeds and insects have an excellent opportunity to become established in your lawn.

141. Is it true that soft water is harmful to grass?

Generally no. Soft water is merely water free of the calcium and magnesium salts. However, sodium has been added to the water in the process of removing the hard salts, and excess sodium in the soil can be harmful.

142. Why does the ground under the shade trees always dry up so quickly, even after a heavy rainstorm?

To a very large extent, the natural canopy the tree forms pre vents the rainfall from penetrating the ground. This means less natural moisture accumulates under the trees, and extra water must be added by sprinklers. The roots of most shade trees are very shallow and compete with the grass for any moisture present in the soil.

143. How can I measure how much water I’m getting on my lawn when I sprinkle?

Set several cans in a straight line at different distances from the sprinkler. Run the sprinkler for one hour and then measure the depth of the water collected in each can. Divide by the number of cans used, and the answer will be how much water your sprinkler delivers in one hour. If the sprinkler delivers one-half inch of water per hour, then you would have to operate the sprinkler for two hours to get one inch of water on your lawn. The water in the cans will also indicate whether the sprinkler is distributing the water uniformly over your lawn. (See fig. 5—1).

Figure 5—1. Checking water distribution from a sprinkler.

144. I know water is necessary for a plant to live, but no one has ever told me why. Can you?

The majority of the nutrients in the soil are dissolved in water and move to the roots this way. Probably the most important function of water in a plant is the role it plays in photosynthesis. This process uses sunlight, carbon dioxide, and water and, through a series of chemical reactions, produces the food the plant needs. (See Table 5—2.)

TABLE 5-2 Water Requirements of Plants

Type of Plant

Pounds of water required to Produce 1 pound of dry matter


Kentucky bluegrass


Lamb’s quarters





145. Since the top part of the plant is exposed to plenty of air, why does the soil need to have so much air in it?

The aboveground parts of a plant usually do not absorb any oxygen from the atmosphere but instead absorb carbon dioxide and in turn release oxygen back into the atmosphere. This is how your lawn is doing its share to help prevent air pollution. It not only removes pollutants (carbon dioxide) from the air but also replaces them with oxygen.

Just the opposite situation occurs below the ground level. The roots of the grass plants require oxygen to survive, and they remove oxygen from the soil air spaces. If all of the air spaces are filled with water, due to overwatering or heavy rainfall, then the roots cannot function at their best, with the upper portion of the plant suffering, turning yellow, and even dying because of the lack of oxygen.

146. How soon after I apply a pesticide may I water my lawn?

This would depend on the chemical you have applied and what pest you are trying to kill. Read the label on the pesticide container and see if it tells you when to water after applying the chemical. If you are not trying to kill a pest that lives in the soil, you probably should let the chemical dry on the plant 12 hours before watering. If you want to kill lawn grubs, cutworms, or any pest that lives in the soil, then water immediately after applying the chemical. This concentrates the chemical right in the soil where the pest will come in contact with it.

147. What are some management practices I can use to reduce the amount of water needed by my lawn?

Mowing your grass at the proper height is a good start. Mowing too short puts the grass under a stress and causes it to use more water to overcome it. Overwatering reduces root growth. Moreover, the plant is capable of absorbing more water than it actually needs, so to prevent the plant from wasting water, do not over water. Proper fertilization will help to conserve water. Over-fertilizing stimulates the grass to grow rapidly and causes it to require larger quantities of water.

148. Why does the grass always turn brown so quickly next to the south side of the house?

There is a good chance that, when the foundation of your house was built, the contractor filled along the wall with rocks, boards, and other odd bits of construction material. Often this is done to within a few inches of the surface of the ground, then covered with soil, tamped, or water-soaked to settle the area. This compacted soil does not absorb water very readily, so the grass plant has a difficult time growing in it.

Two other factors that could be involved in this problem are the eaves on your house and the sunlight. The eaves keep the rain water from dripping on the ground next to the house, especially since most houses have rain gutters on them. This means there is a natural tendency for areas next to the house to dry out more quickly than the rest of your lawn. The sun adds to the problem by reflecting off the side of your house and evaporating the water from the soil next to it.

149. What is the best type of lawn sprinkler for watering my yard? Each of the several different types on the market today does an adequate job provided you make sure the water coverage is correct. Two of the better types are the oscillating-wave sprinkler and the impulse-oscillating sprinkler.

The wave type often soaks the soil the deepest near its base, so when it is reset to a new location you should allow for a 50 percent overlap of the last sprinkler pattern. The impulse-oscillating sprinkler does a good job of wetting the soil evenly unless there is a strong wind or a slope. Regardless of the type of sprinkler you use, put some cans out and test the coverage.

150. Does it matter what size hose I use when watering the yard? Garden hoses usually come in two standard sizes: 1/2-inch diameter and 3/4 diameter. You should select a hose that is the same size as your water pipes. If the hose is smaller, you decrease the water pressure and volume of the water moving through the hose. This means you won’t get as large an area watered per sprinkler setting, and it will take longer to water your lawn.

151. I would like to install an underground sprinkler system in my lawn. Is it reasonable to think I can do it myself?

Yes. You can rent a trencher, buy the pipe and necessary fittings, and install your own underground system, but you better be sure you know what you are doing before you start. Poor sprinkler coverage, low-water pressure at the end of a line, and an insufficient water supply can cause your sprinkler system to fail if you have not sized all the pipe and sprinkler heads correctly. My ad vice is to let a professional irrigation company design the system for you; then the chances of a self-installed sprinkler system working correctly are good.

152. A salesman told me to be sure and use a vacuum breaker when I installed my underground sprinkling system. What is a vacuum breaker?

Vacuum breakers are specialized valves that stop irrigation water from flowing back into the potable water supply. State and federal laws require the use of vacuum breakers to prevent the contamination of city water supplies.

153. What type of pipe should I use for my underground sprinkling system?

There are three types of piping material you can choose from — galvanized pipe, copper tubing, and plastic pipe. Three good reasons why you should consider not using metal pipes: (1) it will cost you more for the material, (2) metal piping is more difficult to work with, and (3) the metal piping will eventually corrode and begin leaking.

Plastic piping is the best product on the market for under ground installations of irrigation systems. It is inexpensive, easy to work with, and does not corrode. Special plastic fittings are available, so you don’t have to be an expert plumber to work with this type of piping.

154. What can I do to help the water soak into my lawn instead of puddling and running off into the street?

If the water cannot penetrate into the soil fast enough to pre vent runoff, try punching holes into the soil. This will allow the water to move into the soil more quickly. Another solution to the problem is to apply the water slowly as a gentle spray rather than rapidly as big droplets. You will have to leave the sprinkler longer in each spot, but you will not waste as much water and you will save money.

155. I have read that I could add soap to my water and thus help the water penetrate into the soil. Is this true?

The use of surfactants (chemicals that increase the penetration ability of water) is a common practice by professional turf people, but they use a surfactant only for highly specialized reasons. A small amount of soap in your water may act as a surfactant, but actually there seems to be very little advantage in using a surfactant on home lawns.

156. What are some of the problems caused by overwatering a lawn?

Overwatering causes the grass to be shallow-rooted, which means it will wilt easily in hot weather. Waterlogging a soil encourages water-loving plants (nut sedge, annual bluegrass, bentgrass, and nimblewill) to invade your lawn. Another major problem is an economic one. Overwatering is hard on your pocketbook and your water supply.

157. Can frequent watering of a lawn also damage it?

Yes. Frequent watering also encourages the grass to be shallow rooted. Small amounts of water applied too frequently may result in annual weeds (crabgrass, shepherd’s-purse, button weed, and verbena) and once they germinate, these weeds quickly become established in your lawn and become a nuisance.

158. Can you tell me how much water the grass growing under a tree requires?

A very general rule you can use is to water the grass growing underneath your trees twice as much as the grass out in the open areas. This will supply the trees, as well as the grass, with the water they need.

159. Are there any grasses that require very little water to 8urvive extremely hot weather?

Bermudagrasses and bluegrasses require constant watering throughout the growing season or they go dormant and turn brown. The same is true of most of the Southern and Northern grasses. In the arid parts of the United States, there are grasses that can survive on very little water; however, most of them are not very attractive and do not make a nice lawn. Nevertheless, these grasses (crested wheat, buffalograss, lovegrass, and the gamma grasses) can be used for lawns where water is scarce.

160. Does the way I mow my lawn have any affect on how frequently I should water the grass?

Definitely! The height of cut and frequency with which you mow your lawn both affect how often you will have to water your lawn. Close (short), frequent mowing causes the root system of a grass to be very shallow, thus reducing the area it can draw moisture from. Mow your grass high and less frequently and the grass roots will go deeper into the soil, increasing the area in which they can draw moisture, and lengthening the time between waterings.

161. Can I add fertilizer to the water so that as I sprinkle my lawn I will also be fertilizing it?

This can be done if you have the proper equipment. Green houses use this procedure frequently, but for a home lawn it is not very practical. It requires an understanding of how to mix the water and fertilizer in the correct proportions, and complete attention while the operation is in process.

162. Water is extremely expensive where we live (desert area), and the heat during the day is unbelievable. What, besides grass, can I use?

In the hot, arid regions this is a very common problem, and many people solve it by not growing grass. Some have rock and cactus gardens, while others have spread small (pea-size> gravel and sprayed it green to give the appearance of a lawn. If water is scarce and you don’t want to grow grass, then you are limited as to what you can do.

163. I read where you can literally drown your lawn by overwatering. How is this possible?

It may seem ridiculous, but you definitely can drown your grass by watering too much. Oxygen is necessary if a plant is to survive, and the roots of the grass plant remove oxygen from the soil. If the water forces all the air out of the soil, the plant cannot survive and slowly dies from the lack of oxygen.

164. What are some of the advantages to having an underground sprinkler system?

There are several advantages, but the two most important ones are the reduction in cost and the decrease in labor in watering your lawn. Usually an underground system allows you to water your entire lawn uniformly and reduces oversoaking of some areas and underwatering of others. The time saved in dragging hoses around your lawn and having to constantly check the sprinklers gives you more time for other activities. Another advantage is that the beauty of your lawn is not marred by having sprinklers and hoses all over the yard.

165. What does my neighbor mean when he says his new sprinklers have pop-up heads?

Pop-up is a term used for sprinkler heads that are flush with the ground until the water is turned on. The water pressure forces the sprinkler heads to pop up Out of the ground about two to three inches. When the water is turned off, the sprinkler heads fall flush with the ground and are out of the way for mowing and other yard activities.

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