Brown Spots, Broken Heads and Sprinkler Coverage Problems …..

A number of factors can lead to poor coverage of turf and landscape areas resulting in brown patches and uneven plant growth. In some instances, there is a specific problem with the sprinkler equipment. In other cases, the system design or operating pressure need to be investigated.

Incorrect Sprinkler Height. One of the most common and recurring problems resulting in poor coverage and damage to sprinkler systems is the improper installation height of individual sprinkler heads.

Sprinklers installed too low can not rise above the turf or other plant materials. This results in an interruption of the sprinkler’s pattern of throw and can lead to gaps in coverage and flooding near the sprinkler. In addition, sprinklers installed too low are more prone to retraction problems and pre-mature failure as soil enters into the operating mechanism.

In shrubbery areas, heads may be located at the base of the shrubs or groundcover they are watering. These heads must be close enough together to cover the area by throwing water under the plant material. As shrubs mature, adjustments may be necessary to ensure coverage is still adequate .

In many cases where heads were installed correctly, the turf builds up and grows with time, causing the heads to be too low relative to the surrounding grass. All systems should be periodically checked to make certain grass or plantings do not interrupt sprinkler patterns.

Sprinklers installed too high are an invitation to damage by mowing equipment or vandalism. They can also be a trip hazard resulting in unwanted liability. Sprinklers which are installed too high should be corrected before damage or injury occurs.

Tip: Avoid trimming digging out divots around sprinkler heads or using a weed-eater to trim away grass each week.

Should problems with sprinkler head height appear within the first year or two of a system’s life, contact your irrigation installer if you are within your warranty period. Otherwise, any irrigation contractor can resolve the problem.

Clogged Sprinkler Nozzles: Dirt or debris which finds its way into sprinkler nozzles can quickly disrupt sprinkler spray patterns. Even in systems with heads spaced correctly, clogged nozzles can cause uneven coverage. The first step in evaluating the cause of dry areas is to observe the spray pattern of each head in the zone.

Note: Do not attempt to remove nozzles by gouging or prying at the orifice. Nozzles are easily damaged by hard metal objects like screwdrivers.

Contact your irrigation contractor if clogged nozzles are a problem.

Incorrect Sprinkler Head Spacing: Often in watching a system operating, the casual observer may conclude that full, even coverage is being achieved because heads are throwing water over a given area.

Manufacturer’s specifications require what is referred to as "head to head" coverage. Each head is expected to throw far enough to touch the adjacent heads and vice versa. This type of coverage allows for optimum overlap and compensates for any potential imperfections in spray pattern or other conditions which may affect complete, even coverage.

Unevenness in lawn color or brown patches can indicate poor coverage. Systems having poor coverage will show their weakness during extreme dry conditions or when new installations require even watering because plantings have yet to develop mature and spreading root systems. Additional watering time and hand watering can sometimes help to resolve the problem, however basic adjustments to the system made by an irrigation professional may be the only real solution. See also Water Audits