Overwatering Ponderosa Pines: Correcting Daily Irrigation Schedule

200 ponderosa pines on drip irrigation in eastern WA. Increased from every 3rd day to daily 45-min cycles during 90°F+. Trees now show drooping tops, sagging limbs. Overwatered? Reversible? Fertilize young pines?

Watering Principle

Trees need water based on rainfall deficit, not temperature. Target: 1 inch/week deep (8–10" soil moisture). Light daily watering → shallow roots → drought vulnerability.

Correction

• Water deeply now, then weekly 1-inch schedule when no rain
• Test: pan under drip line measures output
• No fertilizer – 18" spring growth indicates sufficient nutrition