Lawn Sprinkler Tips

Have you checked your rain sensor lately? Does your automatic lawn sprinkler system even have a rain sensor? Since 1991 there has been a mandatory law here in Florida that states that all automatic lawn sprinkler systems installed after that date must have a rain sensor device installed.

If you don’t already know, a rain sensor is a small piece of equipment that hooks up to your sprinkler system and shuts they system down if there is adequate rainfall. Most brands of rain sensors can be adjusted to shut the system off from 1/8″ to 3/4″ of rain.

The way most rain sensors work is by a small cardboard like material disc that swells out when it becomes saturated. When the disc swells out, it puts a break in the common or negative wire(s) in the system which in turn doesn’t allow the pump to turn on or electric valves to open.

Even though there has been a law in effect that requires rain sensors, many systems still don’t have them. The law is not heavily enforced, and there are certain areas that don’t require inspections and therefore the contractor or homeowner can get by without installing one.

Although beneficial to saving water and not overwater the lawn some contractors feel that rain sensors are a hassle. I agree that they can be, especially when the homeowner or customer doesn’t know that their sensor is set for a specific amount of rainfall. You may get a call from someone who says “it’s raining, but my system is still running”, but the sensor may have not yet measured enough rain.

You also get calls when people don’t see there system run a day or two after it rains. This is because it could take a couple of days for the disc to dry out let the system go back to operational. The rain sensor is designed to dry out at approximately the same rate as the soil.

Overall, I do recommend the use of rain sensors. Especially when you are using metered (city) water and are paying for the use. This small device could save you hundreds or more dollars a year and it will also prevent overwatering of your lawn. Overwatering of your lawn could lead to fungus, yellowing and overall poor health of your lawn.

Scott
http://www.autolawnsprinklers.com

One of the main tasks of designing an irrigation system is the sprinkler head layout. The sprinkler head layout consists of deciding what kind of sprinkler heads will be used and where exactly they will be placed. When I do a layout I place flags in the yard representing where each head will go.

I continue to mark out the sprinkler heads, using different color flags for each individual zone. For example, the front right spray zone may have blue flags at each spot where a spray heads will be placed, a side spray zone may have orange flags, and a back rotor zone would have red flags.

Keeping each zone its’ own color will help you with the building of your sprinkler system so that you don’t mix the wrong heads on a particular sprinkler zone.

When laying out your lawn sprinkler system remember to not mix rotors and spray heads as I mentioned in my previous article. Rotors and sprays put out water at a different rate so you’ll want to keep them separated.

Rotor heads typically throw 30 feet and can be reduced slightly if needed. Sprays can throw from 4 feet to 18 feet depending on what type of nozzle you use. Rotors can usually be adjusted from about 25 degrees to 360 degrees radius. Spray nozzles come in either fixed or adjustable pattern radius. I try and stick with fixed nozzles (ie. 15 half, 10 quarter, 12 full ect…) because they have a better spray pattern and don’t tend to get clogged like the adjustable pattern sprays.

Overall the most important factor when doing a lawn sprinkler head layout is to make sure that you have “head to head” coverage. What this means is that the water from one sprinkler head reaches the next sprinkler head in the yard. This will ensure even precipitation and “double coverage” which is essential to a proper lawn sprinkler design.

So remember when designing out your lawn sprinkler system to make sure that you don’t mix rotors & sprays, you have double or “head to head” coverage, and use different color flags to represent the different zones.

Often when I am giving a bid or an estimate on a sprinkler system I get asked whether I will be using rotors or sprays. Not everyone asks this question, but those who’ve learned information about irrigation and lawn sprinklers tend to ask.

The answer that I give people is “we use a combination of rotors and sprays depending on the landscape.” When I say a combination I don’t mean that you mix rotors and sprays on the same zone, I mean that you will use rotors in the larger turf areas and sprays in the flower beds and smaller grass areas.

Rotors have a smaller precipitation rate than spray heads. That means that they take longer to get the same sized area wet and spray heads water an area quicker. Spray heads just pop up and don’t rotate, while rotors have to turn to water the area that they are designed to water. This is why it is not a good idea to mix rotors and sprays; because you will either overwater or underwater a section of that zone.

Frequently with certain designs and curves of a landscape, a spray head may need to be added to a rotor zone. Sometimes it is just impractical to have to run a separate line just to add one spray head, so you break the “rule” and add one head. With sandy permeable soil, you can tend to get away with this with little bad effects, but with a denser soil I would not recommend it.

If you can space your heads 25 -35 feet apart then you should use rotor heads. Rotors have bigger water droplets, don’t get clogged like sprays, and cover a larger area than sprays. Spray heads are good for areas where you can space heads 4′ to 15′ apart. Spray can work better with landscapes with a lot of curves, and will water an area quicker, but they will get clogged more often when using a well supply.

That’s all for now. Have a happy 4th of July tomorrow!