If you’ve ever wondered whether your irrigation system is running too much or too little, you’re not alone. Irrigation scheduling is one of the most common areas where homeowners get things wrong, not out of negligence, but because the right answer isn’t obvious and the consequences of getting it wrong are slow to appear. Grass that’s been underwatered for two weeks looks a lot like grass that’s been overwatered for two weeks. By the time the damage is visible, the cause is already in the past.
At Mainely Irrigation, a Division of Just Grass, Inc., we design, install, and service irrigation systems throughout the greater Bucksport, Maine area. One of the most common questions we get from clients, especially in the first season after a new system goes in, is simple: how long should I run it? This guide answers that question in full.
The Baseline: What Cool-Season Grasses Actually Need
Maine lawns are composed primarily of cool-season grasses: Kentucky bluegrass, fine fescues, tall fescue, and perennial ryegrass. These species grow most actively in spring and fall when soil temperatures are between 50 and 65 degrees. In the summer months, they slow down and can enter a semi-dormant state when conditions are hot and dry.
The widely accepted water requirement for cool-season lawns is 1 to 1.5 inches of water per week during the active growing season. That figure includes both rainfall and irrigation combined. In a week with half an inch of rain, your system should supply the remaining half to full inch. In a week with no rain, it should supply the full amount.
That sounds straightforward, but Maine’s summer weather makes it complicated. We can go from a week of daily showers to a two-week dry stretch with very little transition. If your irrigation system is running on a fixed schedule with no adjustment for rainfall, you’re either wasting water during wet periods or falling short during dry ones.
What “An Inch of Water” Actually Means in Practice
An inch of water sounds like a measurement from a rain gauge, which is exactly right. One inch of water applied to one square foot of lawn equals about 0.623 gallons. For a 5,000 square foot lawn, delivering one inch of water means applying roughly 3,100 gallons. That’s a meaningful volume, and it has real implications for both your water bill and how you schedule run times.
Not all irrigation heads apply water at the same rate. Spray heads typically apply water at a rate of 1.5 to 2 inches per hour. Rotor heads apply it much more slowly, typically 0.4 to 0.8 inches per hour. This means a zone with spray heads needs to run for 30 to 40 minutes to apply an inch of water, while a rotor zone may need to run for 75 to 90 minutes to deliver the same amount.
The only reliable way to verify what your system is actually putting down is the catch cup test. Place several straight-sided containers (tuna cans work well) around an active zone while it’s running. After 15 minutes, measure the depth of water in each can. That number, multiplied by four, tells you your application rate in inches per hour. If your cans average a quarter inch in 15 minutes, your zone is applying one inch per hour and needs to run for 60 minutes per week to hit the target.
We recommend running this test when a new system is commissioned and whenever you notice coverage inconsistencies. It takes 20 minutes and gives you real data to base your schedule on.
Maine Soil Type Changes Everything
The 1 to 1.5 inch weekly figure is a general target, but how you deliver that water matters as much as the total volume. Soil type determines how quickly water is absorbed, how long it’s retained, and how often you need to water.
Sandy soils, which are common in coastal areas of Downeast and Midcoast Maine, drain quickly. Water passes through the root zone fast, which means the lawn dries out sooner. Sandy soil lawns benefit from shorter, more frequent watering cycles. Instead of applying one inch once a week, you might apply half an inch twice a week to keep moisture available in the root zone continuously.
Clay and loam soils, more common in the Bucksport and inland Hancock County area, absorb water more slowly and hold it longer. These soils are prone to runoff if water is applied faster than the soil can absorb it. A zone with spray heads running over clay soil for 30 consecutive minutes may lose a significant portion of its water to runoff before the soil has a chance to absorb it. Breaking the run time into two cycles with a soak interval in between (called cycle and soak) addresses this effectively. Run a zone for 10 minutes, wait 30 to 60 minutes for absorption, then run it again. The total water applied is the same, but the runoff loss is dramatically reduced.
When Mainely Irrigation designs a system, soil type is one of the first factors we account for. The zone configurations, head types, and run time recommendations we provide at startup are built around your specific soil.
Morning Watering: Why It Matters
The best time to run your irrigation system is early morning, between 4:00 and 9:00 a.m. The reasons are practical and significant.
Watering in the early morning gives your lawn time to dry before temperatures peak. Wet grass blades in full sun heat up quickly and dry out by midday, which is ideal. Watering in the evening or at night leaves grass wet for extended periods, which creates conditions favorable for fungal disease. Dollar spot, red thread, and brown patch are all common in Maine lawns during humid summer periods, and consistent evening irrigation encourages all of them.
Watering in the middle of the day wastes water. Wind and evaporation losses during afternoon hours can reduce irrigation efficiency significantly. Water applied at noon in 85-degree heat with a light breeze may lose 20 to 30 percent to evaporation before it ever reaches the soil. Early morning air is typically calm and cool, and evaporation losses are minimal.
If your controller is currently set to run in the evening or midday, adjusting the start time to early morning is one of the most impactful changes you can make to your irrigation routine.
Deep, Infrequent Watering Builds Better Roots
One of the most important irrigation principles that homeowners often miss is this: how you water shapes how deep your grass roots grow. Roots grow toward water. If your lawn is watered lightly every day, roots stay shallow because they find water near the surface. Shallow roots make a lawn vulnerable to drought stress, heat damage, foot traffic compaction, and disease.
Deep, infrequent watering encourages roots to extend further into the soil profile in search of moisture. A lawn watered to a depth of 6 to 8 inches twice a week develops a deeper, more resilient root system than a lawn that receives the same total volume spread across daily light applications. When a dry spell hits, the deep-rooted lawn draws on a larger reserve of soil moisture and stays green longer before showing stress.
For most Maine lawns, watering two to three times per week rather than daily is the right approach. The goal is to apply enough water each cycle to wet the soil to a depth of 6 to 8 inches, then let the top inch or two of soil dry before watering again. That drying cycle encourages roots to extend downward.
To check your watering depth, push a screwdriver or soil probe into the lawn an hour after a watering cycle. It should penetrate easily to 6 inches or more. If it stops at 3 to 4 inches, your run times are too short. If the soil is saturated at 12 inches, you may be overwatering.
Seasonal Scheduling Adjustments
A single schedule set in May will not serve your lawn well in July, and it definitely won’t be right in September. Maine’s seasonal variation in temperature, rainfall, and grass growth rate requires corresponding changes to your irrigation schedule.
In spring, cool temperatures and frequent rainfall mean your lawn needs much less supplemental irrigation than it will in summer. Running your system at full summer capacity in May risks overwatering, encouraging disease, and promoting excessive top growth that outpaces root development.
In summer, particularly during dry stretches in July and August, water demand peaks. Heat accelerates evapotranspiration, the process by which plants and soil release water into the air. Your system may need to run at full capacity and still only meet your lawn’s needs on the driest days.
In early fall, temperatures drop and grass enters its most vigorous growth period of the year. Fall is when cool-season grasses actively repair summer stress, and consistent moisture is important for that recovery. Irrigation should continue through September and into October in most years, tapering off as temperatures drop and rainfall increases.
Smart Controllers: Scheduling That Adjusts Itself
The most effective solution to Maine’s variable summer weather is a smart irrigation controller. Smart controllers connect to your home’s WiFi and pull local weather data, including temperature, humidity, wind, and rainfall totals, to calculate daily evapotranspiration and adjust your watering schedule automatically.
On a day when significant rain falls, a smart controller skips the irrigation cycle. During a heat wave with low humidity and strong winds, it increases run times to compensate for elevated evapotranspiration. The system responds to actual conditions rather than running on a fixed schedule set months ago.
According to the EPA WaterSense program, smart controllers can reduce irrigation water use by up to 50 percent compared to traditional timer-based systems, without any sacrifice in lawn quality. For a Maine property that sees swings between wet springs and dry summer stretches, that efficiency gain is genuine, not theoretical.
Mainely Irrigation installs and programs several leading smart controller brands. We configure your initial schedule based on your soil type, head types, and zone coverage, and we walk you through the smartphone app so you can monitor and adjust your system from anywhere.
When to Call for a Scheduling Review
If you’re not sure whether your current schedule is calibrated correctly, we’re glad to help. Signs that your schedule may need adjustment include areas of the lawn that are consistently dry, zones where water is visibly running off before being absorbed, unusually high water bills without a change in lawn size, or grass that looks stressed even during periods when the system appears to be running normally.
Mainely Irrigation provides scheduling consultations as part of our ongoing service work throughout the greater Bucksport, Maine area. Whether you’re in your first season with a new system or managing one that’s been running for years, getting the schedule right is the foundation of everything else.
Call us at 207-702-9074 or contact us online to schedule a service visit. As a Division of Just Grass, Inc., we pair irrigation expertise with deep knowledge of Maine lawns and landscapes, and we’re here to help your property look its best through every season.