Irrigation Programming Guide

Written By Andrew Kenley

1. Frequency:

✅ Benefits:

  • Mimics natural rainfall

  • Promotes deep root systems

  • Increases pest, disease, and drought tolerance

⚠️ Not Recommended for New Sod!

Watering Guidelines

🌿 Sub-90°F with Moderate/Light Drought:

  • 3–4 days per week, depending on sun exposure

🔥 90°F+ with Severe Drought:

  • 4–5 days per week, depending on sun exposure

🌱 New Sod Establishment:

  • 5–7 days per week, adjusted for temperature, drought severity, and sun exposure

💦 Supplemental Cycles:

  • Use Program B, C, or D for additional watering of potted plants, annuals, or unique landscaping features that may dry out faster.

2. Start Time:

✅ Water Early – Around 5 AM

  • Reduces evaporation loss

  • Allows moisture to be absorbed efficiently before the heat of the day

  • For even better results, use multiple start times (see Section 5 for details)

🚫 Avoid Watering During the Day

  • High evaporation rates make it inefficient

🚫 Avoid Watering Late Afternoon or After Sundown

  • Prolonged moisture on leaves increases the risk of fungal diseases

Special Cases: New Sod & Potted Plants

🌱 May require extra watering in the afternoon to prevent drought stress
💦 Use "Program B, C, or D" for supplemental cycles
⚙️ This is considered advanced programming but ensures optimal hydration for sensitive plants

3. Know your Zones:

Before setting up your irrigation system, it's critical to identify the type of heads in each zone.

1️⃣ Spray Zones (Fixed Spray Heads)

  • Produce a fine mist

  • Typically found in small grass patches or landscaped beds

  • High water output – up to 3X more per minute than other head types

  • Requires shorter run times

2️⃣ Rotary Zones (Rotors & Rotary Nozzles)

  • Heads rotate or oscillate to cover larger areas

  • Common in large turfgrass areas

  • Water is distributed over time, covering only a fraction of the area at any moment

  • Requires longer run times to ensure full coverage

3️⃣ Mixed Zones (Spray & Rotary Heads Together)

  • Contain both spray and rotary heads, making watering uneven

  • Problematic because of vastly different water output rates

  • Compromise is necessary, often leading to some areas being overwatered and others underwatered

💡 Tip: Whenever possible, separate spray and rotary heads into different zones to improve watering efficiency and consistency!

4. Duration:

Understanding the type of head or nozzle in each zone is key to setting the correct runtimes.

Spray Heads (Fixed Spray Nozzles)

💧 Run Time: 9–12 minutes

  • Adjust based on plant type and sun exposure.

  • Example:

    • Boxwoods in partial sun → ~9 minutes

    • Boxwoods in full sun → ~12 minutes

Rotating Heads (Rotors & Rotary Nozzles)

💧 Run Time: 24–45 minutes

  • The greater the rotation and more sun exposure, the longer the runtime.

  • Example:

    • 180° rotation in full sun → ~36 minutes

    • Smaller rotations → ~24 minutes

    • 360° rotation → Up to 45 minutes

Special Considerations:

🌱 New Sod – Needs shorter, more frequent watering:

  • Spray Heads → ~4 minutes

  • Rotary Heads → ~12 minutes

🪴 Potted Plants – Fully saturate in ~3 minutes but dry out quickly.

  • Multiple daily cycles may be needed in hotter months.

Setting the right runtimes ensures efficient watering and healthy plant growth! 🌿💦

5. Cycle and Soak:

“Cycle and Soak” is an irrigation programming method designed to maximize water absorption and minimize runoff.

  • Dry and overly saturated soils struggle to absorb water efficiently.

  • First cycle: Moistens the soil, preparing it for deeper absorption.

  • Second cycle: Water penetrates further into the now-prepared soil.

  • Final cycle: Pushes moisture deep into the roots without oversaturating the topsoil.

This method is especially important for deep root watering and sloped landscapes, ensuring water reaches the root zone without waste or runoff.

  • 1️⃣ Program 3 Start Times:

    • 1st Start Time: 2:00 AM

    • 2nd Start Time: 4:00 AM

    • 3rd Start Time: 6:00 AM

    💦 How It Works:

    • Your irrigation will run through all zones 3 times on scheduled watering days.

    • This effectively multiplies the runtime of each zone by 3.

    2️⃣ Adjust Each Zone’s Runtime:

    • Divide the total duration needed by 3.

    • Example: If a zone requires 30 minutes total, divide by 3 start times → 10 minutes per cycle.

    • After all three cycles (2, 4, and 6 AM), the zone will have received its full 30 minutes of watering.

    🔁 Repeat this process for EVERY zone to ensure even water absorption and minimal runoff.

6. Seasonal Adjust %:

This feature allows you to set your irrigation schedule once and make seasonal adjustments without reprogramming each zone as weather conditions change.

How It Works:

  • Set your controller for peak watering conditions (HOT & DRY).

  • Adjust watering days manually based on weather (macro adjustment).

  • Fine-tune watering levels using the "Seasonal Adjust %" feature (micro adjustment).

Using Seasonal Adjust (%)

  • Round the average weekly temperature up to the nearest 10 to approximate the correct adjustment.

    • Example: If the average temperature is 85°F, set the Seasonal Adjust to 90%.

  • Start each season in April - May, around 60%

  • Keep adding % until you reach 100% before adding days to your irrigation cycle.

    • You can go beyond 100% if necessary.

⚠️ Some controllers use this feature differently and treat 00% as 100% of the schedule.

  • On these controllers:

    • "-10%" = 90% watering on a standard controller

    • "+10%" = 110% watering on a standard controller

This system-wide adjustment makes seasonal tweaks quick and easy, ensuring efficient watering year-round!

Andrew Kenley
Previous

DIY Irrigation System
Next

Armyworms