Irrigation is an important part to successfully growing fruits, vegetables, and turfgrass. When irrigating, the entire root zone of the plant, which can be several inches deep, needs to be wet. Irrigating only the top of the soil and not the entire root zone will cause roots to stay near the surface. Shallow rooted plants will readily show signs of nutrient deficiencies. Also, not irrigating the entire root zone can lead to drought stress on the plants. Drought stress can cause a delay in maturity, will greatly reduce the harvest in many fruits and vegetables, can lead to cracked produce, and can even cause blossom end rot in some crops. The following information outlines several best practices for irrigation.

Irrigation for Fruits and Vegetables

Frequent irrigation events are recommended for vegetables and other shallow rooted crops. Vegetable crops need 1 to 1.5 inches of water per week. Every farmer and gardener needs a rain gage in order to keep up with how much additional water is needed. Remember, getting 3 inches of water one week does not supply adequate water for the next two weeks. On average, one inch of water per week was applied, but in reality the plants have been suffering from drought for two weeks. With the amount of time and effort spent pruning, training, managing weeds, mulching, staking, etc. to produce fruits and vegetables, producers do not want a lack of water to prevent them from making a crop.

Drip Irrigation

Drip irrigation is the recommended practice for fruits and vegetables. Having irrigation systems in place, specifically drip irrigation, is a great way to improve a garden. While overhead irrigation is an option, this method uses more water, wets row middles where it is not needed, and increases disease problems. Drip irrigation conserves water by directing water to the root zone of plants where it is needed. Since the water is displaced down the row, garden chores such as scouting or harvesting can be done while irrigating.

Drip irrigation is also economical in price and easy to install. Growers can purchase a thin wall irrigation line called a drip tape. This is a cheaper option and is designed to be used in a vegetable garden for only one year. However, there are some people who have taken good care of the drip tape and were able to use it on a small scale for more than a year. It is common to purchase the drip tape for vegetables with the emitters spaced 12 inches apart.

A thicker-walled irrigation line is used for crops such as blueberry, blackberry, and muscadine plants and can be left in the field for many years. These thicker walled lines can be used in a vegetable garden for many years. However, when doing this, it is recommend to roll these lines up and store them during the off season. A line can be purchased and emitters can be manually installed at any distance for plants that may not be evenly spaced. However, it is common to purchase these irrigation lines for blueberries and blackberries with emitters already in the line and spaced 3 feet apart. Even for crops like muscadines that may be spaced 20 feet apart, growers may use lines with the emitters placed every 3 feet apart down the row as well.

Rodents can and will chew into and damage these lines, but it can be easily fixed. With crops that use a trellis such as muscadines, it is easy to install another wire approximately 10 inches off the ground and attach the drip line to the wire. Getting the drip line off the ground will really help the rodent issue.

Amount of Water Per Cycle

Depending on how many gallons of water per minute is available at the site, growers might be able to run the system all at one time or have more than one zone. A water hose, a known container size such as a 5-gallon bucket, and a watch is all that is needed to determine the gallons of water per minute. The most common drip tapes apply 1/2 gallon of water per 100 feet per minute, but a 1/4 gallon per 100 feet per minute drip tape is available. The emitters used for fruit will drip a certain amount per emitter per hour. It is common to have 1 gallon per hour emitters for fruits, but 1/2 gallon and 1/4 gallon per hour emitters are available as well as emitters that drip more than 1 gallon per hour.

The water will spread out better with a slow drip and sometimes growers will cycle the drip irrigation to help the water cover a wider area. Instead of leaving the irrigation on for an hour, it could be run for two, twenty-five minute cycles. This would use less water and provide water over a wider area. It does save water, but can take a little extra time to manage. If the field is on a slope and irrigation water run off is a problem, Extension professionals encourage the use of emitters that apply less water per hour and cycle irrigate. The impact sprinklers for drip systems used on fruits and vegetables run on less water pressure. However, pressure reducers, water filters, fittings, valves, and a supply line to get the water to the field is still needed. All of this can be used from one year to the next, making the system economical.

Irrigation for Turfgrass

Overhead irrigation is used with turfgrass. If producers are able to irrigate their turfgrass, approximately 1 to 1.5 inches per week is needed. The water can be applied at one time or split up into two applications of approximately 3/4 inch each. Producers should put out a rain gauge to determine if the irrigation system needs to be turned on. Do not just have it on a timer that turns on at a certain day of the week. The system should be turned on when a producer knows the turfgrass is not getting adequate rainfall.

Put out rain gauges in different areas of the yard to check if the system us evenly distributing the water. If one zone getting 1 inch and another getting only 1/2 inch, growers might can make adjustments to the sprinkler if they are not working properly. Remember, the impact sprinklers that are commonly used on turfgrass irrigation require a lot of pressure. Producers may need to leave one zone on for a different amount of time than another zone. Remember to irrigate early in the morning to decrease the chance of disease problems. Never irrigate late in the evening or at night.