Controllers & Scheduling — Program Like a Pro
Great schedules start with plant needs, soil, sun, and slope—not guesses. Use this guide to translate measurements (pressure, flow, precipitation rate) into simple, repeatable runtimes with cycle/soak and seasonal adjustments. If hardware isn’t uniform yet, fix coverage and pressure first, then schedule.
What Makes a Good Schedule?
It applies the right depth of water, split into cycles the soil can absorb, at times that reduce wind/evaporation. It adjusts with seasons (ET/weather) and respects real hardware limits: precipitation rate (in/hr), distribution (DU), and pressure at the nozzle.
01 Baseline Data — Zone type (spray/rotor/rotary), nozzle precipitation rate, dynamic PSI, sun/shade, slope, and soil texture.
02 Program by Zone — Set cycle/soak to avoid runoff, choose days by plant need & restrictions, and add seasonal/ET adjust.
When to Use a Smart (WeatherSense) Controller
If you can connect Wi-Fi or a sensor and want the controller to auto-adjust for weather, choose a WaterSense-labeled or ET-based unit. They save water after hardware is tuned (pressure/matched PR). If connectivity is shaky, a simple controller with seasonal adjust + a rain/soil sensor is reliable.
Why Cycle/Soak Works
Matches application rate (in/hr) to soil infiltration so water goes down, not sideways
Prevents puddles on slopes and clay soils
Improves uniformity because every cycle starts on drier soil
Lets you shorten total watering time once coverage is fixed
Controllers & Scheduling — A 10-Minute, Science-First Walkthrough
We’ll build a real schedule from measurements, not myths. You’ll end with simple cycles that work in any climate.
1) Scenario
Yard: Front lawn, mostly sun, slight slope to the sidewalk. Sprays around beds; rotors on the main turf. Summer temps warm, breezy afternoons.
Goal: Deliver the right weekly water to turf without runoff, misting, or swampy edges. Make it easy to dial up or down with seasons.
2) First, Prove the Hardware
Before programming: confirm dynamic PSI is at the nozzle’s spec, coverage is head-to-head, and all nozzles in a zone are a matched set. If not, fix those first—scheduling can’t overcome physics.
3) Collect Zone Data
- Zone type: spray / rotor / rotary nozzle
- Nozzle precipitation rate (PR): from charts (in/hr)
- Dynamic PSI: with the zone running (gauge)
- Soil: sand / loam / clay (feel test is fine)
- Slope & wind: yes/no and typical afternoon wind
- Sun: full / partial / shade
Tip: If you don’t have PR from charts, a quick catch-can test will estimate it. But start with the manufacturer’s numbers—they’re consistent.
4) Pick Practical Water Targets
Cool-season turf often needs ~0.8–1.2 inches/week at summer peak; warm-season turf varies. Start mid-range, then trim once you see consistent color and growth without run-off.
We’ll aim for 1.0 inch/week for this example and adjust with seasonal/ET later.
5) Convert Inches to Minutes (Per Zone)
Minutes per week ≈ Target depth (in) ÷ PR (in/hr) × 60
Example spray zone PR 1.5 in/hr → 1.0 ÷ 1.5 × 60 ≈ 40 min/week.
Example rotor zone PR 0.6 in/hr → 1.0 ÷ 0.6 × 60 ≈ 100 min/week.
Uniformity reality: If you’ve measured DU (distribution uniformity) and it’s, say, 0.6, multiply minutes by ~1/0.6 to cover the low quarter. If you haven’t measured, fix hardware first instead of padding time.
6) Split Into Cycle/Soak to Avoid Runoff
Clay & slopes can’t absorb a long continuous run. Break the total minutes into shorter cycles with soak gaps.
Simple rule: If PR ≥ 1.0 in/hr on clay or any slope, start with 3 cycles. If PR is ≤ 0.6 in/hr on loam, start with 2 cycles.
Our example: Spray zone 40 min/week → 3 cycles → ~13–14 min each. Rotor zone 100 min/week → 2–3 cycles → ~35 or ~3×33 min.
Set Soak gaps 30–45 min between cycles, or stagger by watering other zones in between.
7) Choose Days & Times
Local watering rules aside, early morning (pre-sunrise) reduces wind/evaporation. Avoid late evening if fungus is a concern.
For 1.0 in/week, try 3 days/week in summer peak. Shoulder seasons (spring/fall) can be 1–2 days, or let seasonal/ET adjust do the lifting.
8) Seasonal Adjust (Manual or Smart)
Manual seasonal adjust: In your controller, reduce all runtimes by a % as weather cools (e.g., 80% in early fall, 60% later, 40% in cool/wet weeks).
Smart/ET controllers: Let the controller read weather and adjust automatically. You still set baselines (zones, PR, crop/plant type, soil, slope); it shifts minutes day by day.
9) Respect Microclimates
South-facing strips, reflected heat near pavement, or wind tunnels need more. Shade under trees needs less. Split or reprogram those zones so they don’t fight each other.
10) Fine-Tune With Observation
Look for early stress at the far end of zones and near hardscape edges. Shorten if you see puddles or runoff trails; lengthen if midday footprints linger (wilt footprint test).
11) Rotary & Rotor Notes
Rotary nozzles (multi-stream) apply lower PR, which helps slopes but demands more minutes. Rotors want stable ~45 PSI at the head. If throw is short, don’t add minutes—fix pressure, arc, and nozzle first.
12) Spray Notes
Sprays often mist above ~30 PSI. Use PRS 30-PSI bodies or regulate at the valve. Misting wastes water and ruins uniformity; fix that before scheduling.
13) Sample Program (What It Looks Like)
Program A — Sprays (sunny front beds): 3 days/week, 3 cycles/day × 13 min, soak gap 40 min. Seasonal adjust 100% peak, 70% shoulder, 40% cool.
Program B — Rotors (main turf): 3 days/week, 3 cycles × 33 min, soak gap 40–60 min.
Program C — Shade/low demand: 1–2 days/week, 2 cycles × 8–10 min; seasonal adjust aggressive.
14) Sensors & Add-Ons
Rain sensor: Cheap insurance—suspends watering during/after storms.
Soil moisture sensor: Great for fine soils or microclimate zones; triggers only when soil actually dries.
Flow/pressure sensor: Detects stuck valves, breaks, and verifies dynamic PSI trends.
15) Controller/Wiring Sanity
If a zone ignores or truncates run times, verify you’re on the correct program (A/B/C), check start times aren’t stacked by accident, and confirm 24–28 VAC at the active station. Flaky commons cause “random” behavior.
16) Watering Restrictions
Some cities restrict days/hours. Use cycle/soak to fit inside the window. If you must water fewer days, increase minutes proportionally—but watch for runoff and split into more cycles.
17) Maintenance That Protects Schedules
Clean nozzle screens in spring, level sunken heads, prune overspray blockers, and re-verify dynamic PSI after any plumbing work. Your schedule is only as good as today’s hydraulics.
18) Troubles You Can’t Program Away
Misting/fog: Pressure too high → regulate.
Short throw: Pressure too low or wrong nozzle → fix hardware.
Brown crescents near heads: Arc/level/screen issue → correct pattern.
19) Mini-FAQ
How many minutes should I run? Convert inches to minutes using your zone’s PR, then split into cycles. Minutes follow math; uniformity follows hardware.
Is 3 days/week mandatory? No. It’s a starting point. Hot/windy sites might need more days with shorter cycles; cool seasons need fewer.
Can I mix sprays and rotors on one zone? You can—but PRs differ, so schedules will always be a compromise. Better to separate or re-nozzle to a matched family.
20) Printable Checklist
- Confirm pressure & matched PR per zone
- Collect PR (in/hr), soil, slope, sun
- Pick weekly inch target (start ~1.0 in summer)
- Convert inches → minutes by zone
- Split into cycles; set soak gaps
- Choose days/times; enable seasonal/ET adjust
- Walk, observe, fine-tune; repeat monthly
21) Next Steps
Uneven coverage? Fix Heads & Coverage. Valve behavior odd? See Valve Diagnosis. Want references and nozzle charts? Visit References.