Proper Programming and Watering Instructions for Irrigation Systems

Large corporations, homeowner associations, and golf courses spend a significant amount of money making irrigation audits to maintain water conservation practices and efficient irrigation. These audits are definitely not cost-effective in small or medium residential systems and even in some larger residential systems. Underneath this audit, what are we looking for?  - to save water while maintaining a healthy soil-plant-water relationship, because the audit seeks to provide the appropriate relationship in each case.

The soil-plant-water relationship This is a big new world but in simple terms, it is the interaction of soil and plant properties, and water use that are essential for healthy plant growth. For example, from the point of view of the irrigation, proper and frequent watering (opportunity, location, distribution and quantity), according to with the type of soil and plants it is the key to avoiding putting the plant into stress situations (under-watering will cause stress to the plant and over-watering can cause distress, not to mention stress to your pocket too).

What should the residential homeowner do? Follow the same analysis but in simple levels. Remember you are the host of this relationship and also you should try only to tune up one irrigation system. This means you don’t want huge changes (like add-ons, retrofit, or up-grades). Also, no one knows your property better than you and also what you want, but how can you apply the principles of the soil-plant-water relationship?

First, and before you do anything, perform a walk-around for any obvious landscape issues (like downspout location and drainage problems, deep shade, severe slopes and make a drawing of your lawn. This does not need to be exact, but it will help to remind you of some facts like areas that dry out faster due to southern exposure (full sunlight), shade trees and competition (mature roots), driveway edges (pavement heats up), and low carrying capacity (thin, rocky soil).

Secondly, on this drawing, add the location of each zone and type of heads (rotor, spray, mp rotator). Also if you want, include how they are watering. (90, 180, or 360 degrees) to see in the drawing how will be these will be covered. Additionally, when the contractor finished the installation of the irrigation system, this provided basic information about the design (gallons/min by zone). This is very important information, similar to your car's MPG. If it has been many years and you do not have this information, Contact your service contractor to update the records of your design.

Last it will be necessary to minimize the effect of other variables like wind and sun when setting up the system in the spring. The best way to do this is to choose the appropriate start time. It is best to begin watering before sunrise to reduce loss due to evaporation, but also with enough length of time to get the whole system running before the sun fully rises. Now we have all that we need, we can distribute run times in the best possible way.

Some tips to do this:

Remember that all the irrigation systems can distribute water faster than the soil can absorb it, this is the reason why they need to be customized. Also, the type of soil affects your watering needs (sandy soil absorbs water faster, but retains less and clay soil absorbs slowly).

Infrequent watering is the best possible way to the water. My recommendation is watering every 2 or 3 days according to the season (2 during the summer), leaving time for mother nature to do her work. I do not usually use fixed days in order to follow the random action of rain and I also recommend a highly sensitive, reliable rain sensor. On average, lawns need between 1 – 2 inches of water per week, either by rainfall or in combination with irrigation and to break the running times in 2 shots by day minimum is the best way to help the water soak into the ground and to avoid a run-off. Don’t be afraid to break the running times in 2 or 3 shots because we are not adding more water, we are only distributing the water better and adjusting the watering to soil absorption.

Follow the drawing to begin setting the run times. On average, we should have set run times of between 5 – 10 min for fixed spray heads and 20 – 30 min for rotary heads adjusting the times by sunlight exposure, shade and competition from trees, and delicate watering in flowers bed, for example.

Some other important tips:

According to the distance and location, it might be possible to irrigate particular areas (using an under drip method) by installing downspout rain barrels.

Core aeration will help water absorb into clay soil because the holes will allow easy infiltration of water. Remember, if growth drastically increases, it means you are watering too much, and heads along a driveway or walk will need to overspray a little bit (1 foot) over the pavement to ensure the grass along the edge does not dry out when it is hot.

Tall fescue, Bluegrass, and Perennial Rye require the most water (1 ½” – 2” per/week). Hybrid Bermuda (such as Tifway), St Augustine, and Zoysia grass require (1” – 1 ½” per week) and Common Bermuda and Centipedegrass require 1” per week.