The square footage the leaves cover (e.g., a 2ft x 2ft plant = 4 sq ft).
1 day
2 days
3 days
4 days
5 days
6 days
Every day
Calculation Summary
Total Water Needed per Plant: 0 Gallons/Week
Recommended Runtime per Session: 0 Minutes
Total Weekly Runtime: 0 Minutes
How to Calculate Drip Irrigation Runtime
Setting up a drip irrigation system is the most efficient way to water your garden, but knowing exactly how long to leave the system running can be tricky. Over-watering wastes resources, while under-watering stresses your plants.
Our calculator uses the standard agronomic formula to determine precise runtime:
Step 1: Calculate Gallons Per Week needed based on canopy size. (1 inch of water over 1 square foot is approximately 0.623 gallons).
Step 2: Determine the Total GPH (Gallons Per Hour) delivered to the plant (Number of emitters × Emitter flow rate).
Step 3: Divide total gallons needed by the GPH to find the total weekly hours.
Step 4: Divide the weekly hours by your preferred watering frequency.
Typical Plant Water Needs
Plant Type
Weekly Requirement (Inches)
Notes
Vegetables
1.0 – 2.0
Higher needs during fruiting stage
Shrubs (Established)
0.5 – 1.0
Deep watering encourages root growth
Fruit Trees
1.5 – 2.5
Varies by size and climate
Flowers/Annuals
1.0 – 1.5
Keep soil consistently moist
Real-World Example
Suppose you have a Tomato Plant with a 4 sq. ft. canopy. It needs 1.5 inches of water per week. You have two 0.5 GPH emitters placed at the base of the plant. You want to water 3 times per week.
Gallons needed: 1.5 inches × 4 sq. ft. × 0.623 = 3.74 gallons per week.
Daily runtime: 224 mins / 3 days = 75 minutes per session.
Important Factors to Consider
While this calculator provides a scientific starting point, you should adjust based on your specific environmental conditions:
Soil Type: Sandy soils drain quickly and may require more frequent, shorter runtimes. Clay soils hold water longer and benefit from fewer, longer sessions.
Mulching: Adding 2-3 inches of mulch can reduce water evaporation by up to 50%, potentially reducing your required runtime.
Weather: During extreme heat waves or high winds, increase your runtime by 20-30%.
function calculateDripRuntime() {
var waterInches = parseFloat(document.getElementById("waterInches").value);
var plantArea = parseFloat(document.getElementById("plantArea").value);
var emitterGph = parseFloat(document.getElementById("emitterGph").value);
var numEmitters = parseFloat(document.getElementById("numEmitters").value);
var wateringDays = parseFloat(document.getElementById("wateringDays").value);
var resultBox = document.getElementById("dripResultBox");
// Validation
if (isNaN(waterInches) || isNaN(plantArea) || isNaN(emitterGph) || isNaN(numEmitters) || waterInches <= 0 || plantArea <= 0 || emitterGph <= 0 || numEmitters <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Calculation Logic
// 1 inch of water over 1 sq ft = 0.6233 gallons
var totalGallonsNeeded = waterInches * plantArea * 0.6233;
// Total GPH delivered to one plant
var totalGphPerPlant = emitterGph * numEmitters;
// Total hours per week
var totalHoursPerWeek = totalGallonsNeeded / totalGphPerPlant;
// Total minutes per week
var totalMinutesPerWeek = totalHoursPerWeek * 60;
// Minutes per session
var minutesPerSession = totalMinutesPerWeek / wateringDays;
// Display Results
document.getElementById("totalGallons").innerHTML = totalGallonsNeeded.toFixed(2);
document.getElementById("runtimeMinutes").innerHTML = Math.round(minutesPerSession);
document.getElementById("totalWeeklyMinutes").innerHTML = Math.round(totalMinutesPerWeek);
resultBox.style.display = "block";
resultBox.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}