Target 1 inch of water per week including rainfall

What to Do

Aim for approximately 1 inch of total water per week during spring, counting both rainfall and irrigation. In cool spring weather (April to mid-May), most cool-season lawns use about 1 inch per week. This increases to 1.5-2 inches in summer.

Why It Works

University of Idaho Extension confirms that cool-season lawns use about 1 inch per week in spring. Providing more than this encourages shallow roots, wastes water, and creates conditions favorable for fungal disease. Providing less leads to drought stress and weed encroachment.

Tips

• Use a rain gauge to track natural precipitation and subtract from your irrigation total.
• If it rained three-quarters of an inch this week, you only need to supplement a quarter inch.
• This rule is a starting point — adjust based on soil type, sun exposure, and grass variety.