Spring startup: what to check before you let the system run

Spring startup sounds like the simplest job in irrigation. Turn the water back on, set the controller, walk away. It is also the job where we see the most self-inflicted damage, and almost all of it happens in the first sixty seconds.

Open the main valve slowly. This is the whole warning.

Over winter your irrigation lines are full of air. When you open the main supply valve quickly, water rushes into those empty lines and slams into the first closed valve or capped fitting it meets. That pressure spike is called water hammer, and it is powerful enough to crack fittings, split poly line and blow heads clean off their risers.

The fix costs nothing. Open the valve slowly, perhaps a quarter turn at a time over a minute or two, and let the system fill gradually. You will hear the pipes fill. Wait for that sound to settle before going further. It is the single cheapest piece of maintenance advice in this trade and it is ignored constantly.

Timing it for Tulsa

Mid-March to early April is the window for most of Green Country. The thing you are actually waiting on is the last hard freeze, not the first warm week, and those two are rarely the same event in Oklahoma. A system charged up in February because it hit seventy degrees for three days is a system full of water when the next cold front arrives.

There is no prize for being early. Lawns here do not need irrigation until they are actively growing, and spring rain usually covers the first stretch of the season anyway.

The five things a startup should actually check

A startup is a coverage audit, not a switch. Once the system is pressurized, these are the things worth going through zone by zone:

• Leaks and winter damage. Walk every zone while it runs and look for pooling, soft ground, low pressure and any head that is bubbling instead of spraying. This is where last winter's freeze damage announces itself.
• Head alignment. Heads get knocked out of position by mowers, foot traffic, frost heave and children. A head watering the driveway, the fence or the side of the house is wasting every drop it throws.
• Coverage overlap. Sprinkler heads are designed for head to head coverage, meaning each one's spray should reach its neighbor. Gaps between arcs turn into brown patches by July, and they are far easier to fix in April than to diagnose in the heat.
• Pressure. Low pressure in a zone is the single most common reason a lawn will not green up. If heads are barely rising or the spray is falling short of where it used to reach, something has changed and it needs finding.
• Controller schedule. Programs get wiped by power cuts and stay wrong all season. Rebuild it deliberately rather than assuming last year's settings survived.

Watering deeply beats watering often

While you are setting the controller, this is the habit worth changing. Short daily watering trains grass roots to stay shallow, because there is never any reason for them to go deeper. Shallow roots then cook in the first genuine Tulsa August, and the lawn that looked fine in May collapses in six weeks.

Fewer, longer waterings push moisture further down and pull the roots after it. On clay soil there is a practical limit to how fast you can apply water before it starts running off rather than soaking in, which is why cycle and soak scheduling exists: split a zone's run into two or three shorter bursts with a gap between them, so the ground has time to absorb what it was given.

Early morning is the right time to run, before the wind picks up and well before evening. Watering at night leaves foliage wet for hours, which is an invitation to fungus in a humid Oklahoma summer.

When to hand it over

Plenty of people run their own startup perfectly well, and the slow valve opening is most of the battle. It is worth calling somebody when the system is new to you, when you suspect winter damage, when a zone will not come on at all, or when the coverage has never been quite right and nobody has ever properly audited it.

Pro Sprinkler runs spring startups on any system in the metro, including ones we did not install, across Tulsa, Broken Arrow, Bixby, Jenks, Owasso and the surrounding Green Country towns. If the system was blown out properly in the fall, the startup is usually a short visit. If it was not, the startup is where you find out.