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Seasonal Adjustments to your Irrigation System

Ok, it’s time now for everyone to have their sprinklers on!  Earlier today I was starting up a system for a new customer, and I was struck by how dry the soil was in his lawn, after only about a week of truly spring like conditions.  But even though plants can now use some additional watering, at this time of year, they obviously don’t require as much as they will at the end of July.  But many systems operate by the rule of “Set it and forget it,” whereby once the controller is set in the spring, the program is never modified throughout the season.  Obviously, this is the easiest way to do things, but it’s equally obvious that this isn’t the best way to manage either our water or our landscapes.  So what to do?  There are several options:

      1)  Manually change the schedule in the controller periodically throughout the season- this is the most time-consuming, and possibly confusing, way to deal with the problem.  But if you (or perhaps your gardener or irrigation professional) are comfortable with doing things this way, it certainly can work.

      2) Seasonal Adjustment (or S. A.)- most modern irrigation controllers have a feature called “Seasonal Adjustment” (sometimes also “Water Budget,” or something similar).  This allows a simple universal adjustment of the irrigation schedule, based on a percentage.  As a general rule for most of the season in our region, systems should operate at 80% of the maximum “peak season” run times.  Historically, “peak season” actually only lasts for a few weeks at the end of July and into early August, when our “evapotranspiration” values are at their maximum.  So if the controller is programmed to water a particular area (or “zone” as we usually refer to them) for 10 minutes, it will water it for 10 minutes if the Seasonal Adjustment is set at 100%, but if you adjust the S. A. to 80%, the zone will only be watered for 8 minutes.  So 20 minutes, at 80%, becomes 16 minutes; at 70% it becomes 14 minutes, at 60% 12, etc.  How to change your Seasonal Adjustment: Many controllers have their “Seasonal Adjustment” or “Water Budget” setting on the dial.  To adjust, simply turn the dial to that setting, then use the “+(plus)” and/or “-(minus)“ buttons on the controller to change the setting.  Some Hunter Controllers have the Seasonal Adjustment controlled by 2 up and down arrows located to the left of the LCD display window- just use these buttons to move the Seasonal Adjustment percentage up or down.  Note: some controllers change the Seasonal Adjustment on a Program-by-Program basis.  So if Program A is your lawn, and Program B is your garden beds, you will need to change the S. A. for each separately.  Island Waterwise Irrigation offers a free Seasonal Adjustment e-mail service to our customers, notifying them periodically when we recommend they change their S. A. setting.

      3) Weather Sensors- there are also a number of sensors available on the market, that adjust controller settings based on current or historic weather conditions.  They range from fairly elaborate on-site weather stations, that can measure wind, rain, temperature, and solar radiation, and adjust program run times accordingly; subscription services, linked by computer, that send information to your controller from a regional weather station, or based on local weather records; and simpler devices, such as rain sensors, or one that I’m particularly fond of called the Hunter Solar Sync.  It measures rain, temperature, and solar radiation, and adjusts the controller’s Seasonal Adjustment settings based on the previous day’s weather.  It’s not as complicated as the weather stations, but still uses a good range of onsite data to manage system settings.

 

If you have any questions about any of this, or irrigation in general, please feel free to contact me any time.

 

Best regards,

Mike Isacson, CIC, CID, CIT, CLIA, CIS, CCCT (what do these letters mean? Click here to find out!)

Owner, Island Waterwise Irrigation Inc.

 

Upcoming Events:

 

CRD Irrigation Workshops: Click here to see a full list of CRD irrigation workshops for the spring and summer.  These courses are free, and are targeted at homeowners, with local irrigation professionals, including Island Waterwise owner Mike Isacson, providing a wealth of information.

 

                                                                                                                                                                                   

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