How much water do walnut trees need?
Written by
Liu Xiaohui
Reviewed by
Prof. Charles Hartman, Ph.D.Watering walnut trees requires accuracy. The young sapling my neighbor planted died because of swampy soil, and the 20-year-old black walnut tree I have that receives deep water produces 60 pounds a year. Everything is about balance: too little water and the tree won't grow well, while too much water will drown the roots. Make watering schedules considering the age of the tree and soil type.
Young Trees (1-3 years)
- 10-15 gallons (38-57 L) weekly in dry spells
- Use drip lines to prevent surface evaporation
- Mulch 3 inches deep to retain moisture
Mature Trees (4+ years)
- Deep soak soil to 24-inch depth every 2-3 weeks
- Focus on drip zone (canopy edge)
- Reduce frequency in clay soils to avoid rot
Overwatering Signs
- Yellow leaves despite moist soil
- Fungal growth on trunk base
- Soggy soil 12+ hours after watering
Utilize a screwdriver test to gauge soil moisture. Insert it into the soil; the more resistance you encounter, the drier the soil. If you are working with clay soil, you need to know that it will need to take in about 30% less water than sites with sandy soil. Insert French drains in areas that become wet and prevent root suffocation. Healthy roots smell earthy and not sour.
Changing seasons matter. I irrigate established trees during a hot week in July twice a month, but I do this once a month when the temperatures have cooled in September. Container-grown walnuts need daily attention because their root systems are limited, and they dry out quickly. You can also use 5-gallon buckets with drainage holes when planting patio specimens.
Read the full article: How to Grow Walnuts: 7 Essential Steps for Healthy Trees
