ʻULU PRODUCTION PRIMER
Fertilization Strategies
Nutrition Requirements
Nutrient requirement ratios for breadfruit appear best at 10-4-22-2-2-1 (N, P, K, Ca, Mg, S). At those ratios, a tree producing 300 pounds of fruit per year needs about 2.2 pounds of Nitrogen per year to replace 100% of the Nitrogen removed through harvest. Avoid using too much nitrogen heavy fertilizer blends: this focuses more energy into vegetative growth instead of fruit production.
Download: ʻUlu Nutrient Management Guide (PDF)
This PDF provides an overview of recommended nutrient management practices for mature breadfruit trees.
Watch this video for an informative breakdown of the soil science and plant nutrition behind fertilization, and some best practices for feeding breadfruit trees.
Young Trees – Nutrient Management
For young trees not bearing fruit, there has not yet been conclusive studies indicating best practices for nutrient management. Farmers using conventional techniques may consider a combination of 16-16-16 and Dolomite Ag 10, which has provided good empirical results on Hawaiʻi breadfruit orchards to date.
A general guideline is to apply a total of 2 pounds of 16-16-16 and 0.09 pounds of Dolomite Ag 10 in year one, and increase the amounts slightly each year until the tree begins reaching mature age in year 5. Split total fertilization into 2-4 applications per year, with more frequent applications in rainier areas.
| Tree Age (years) | 16-16-16 (lbs) | Dolomite Ag 10 (lbs) |
|---|---|---|
| 1 year | 2 | 0.1 |
| 2 years | 2.25 | 0.15 |
| 3 years | 2.5 | 0.2 |
| 4 years | 2.75 | 0.3 |
Fruiting Trees – Nutrient Management
If using conventional fertilizers, aim for 10-5-25 NPK ratio ideally; if 10-5-20 fertilizer is more accessible that is also appropriate for most soil types. For a mature tree producing 300 pounds of fruit per year, replacing the nutrients removed through harvest would require approximately 22 pounds of NPK fertilizer and 2 lbs of dolomite per year. Use the chart below to calculate the amount needed for your tree based on harvest amounts.
| Estimated Harvest per Tree per Yr (lbs) | 10-5-25 or similar (lbs) | Dolomite Ag 10 (lbs) |
| 100 | 7.4 | 0.55 |
| 200 | 14.8 | 1.10 |
| 300 | 22.2 | 1.66 |
| 400 | 29.6 | 2.21 |
| 500 | 37 | 2.76 |
Organic alternatives can include Bioflora paired with K-Mag at approximately double the overall poundage listed for the NPK sources. For a mature tree producing 300 pounds of fruit per year, replacing the nutrients removed through harvest would require about 37 pounds of Bioflora per year and 14 pounds of K-Mag. Use the chart below to calculate the amount for your tree based on a harvest amounts.
| Estimated Harvest per Tree per Yr (lbs) | Bioflora 6-6-5 (lbs) | K-Mag (lbs) |
| 100 | 12.33 | 4.57 |
| 200 | 24.67 | 9.15 |
| 300 | 37 | 13.72 |
| 400 | 49.33 | 18.29 |
| 500 | 61.67 | 22.87 |
Natural amendments can be used as an alternative or in addition to conventional management strategies, such as Korean Natural Farming (KNF) inputs like Fish Amino Acid fertilizer, compost teas, and foliar sprays. Seaweed is an excellent fertilizer for breadfruit because it has high potassium and other cations, which breadfruit trees have high demand for.
Check out these resources for KNF farmers in Hawaiʻi:
NEXT: Pruning & Fruit Drop
