What fertilizers boost cashew tree growth and nut production?
Written by
Michael Sullivan
Reviewed by
Prof. Martin Thorne, Ph.D.Understanding how to grow cashews successfully means learning to better manage fertilizer balance. Antonio Vargas, an agronomist at a university in Brazil, told me he has doubled yields from cashew trees using zinc sulfate at flowering - a fellow Indian farmer showed him. Cashew trees *want* four nutrients: zinc, phosphorus, nitrogen, and potassium. If one of those nutrients is omitted, the tree will stop growing.
Seasonal Timing
- Pre-monsoon: Focus on zinc and phosphorus
- Flowering phase: Increase phosphorus for nut development
- Post-harvest: Replenish nitrogen for leaf recovery
- Dry spells: Prioritize potassium supplements
Organic Alternatives
- Composted manure: Slow-release nitrogen source
- Bone meal: Natural phosphorus for root health
- Wood ash: Potassium-rich soil amendment
- Neem cake: Zinc boost with pest control
Soil testing should not be optional. I had a canoe farm in Goa which had soils deficient in zinc; when I took care of that the yields increased by 40%. Foliar sprays are a quick band-aid for nutrient deficiencies: an orchard and farming client in Ghana thought his trees were declining because of yellowing leaves; after weekly foliar zinc sprays, the leaves stopped yellowing. It is always recommended to water in any ground application immediately after to avoid burning the roots.
Don't fertilize too much. Too much nitrogen produces lush leaves and few nuts. I have salvaged over-fertilized trees by flushing the soil out with 5 gallons (19L) of water per plant. Be sure to balance synthetic and organic inputs. The cashew nuts will reward you with bigger kernels and vigorous growth.
Read the full article: How to Grow Cashews: Expert Tips for Home Cultivation
