NPK Ratio

When a program calls for 50 g N + 20 g P2O5 + 30 g K2O per palm per week, the engine has to translate that nutrient demand into a specific mix of fertilizer products from the available pool. A greedy compound-aware solver picks the highest-percentage product per nutrient first: 50 g N comes from 109 g Urea (50/0.46), or 156 g MAP if you also need P (since MAP also supplies P2O5 simultaneously and counts toward both demands). When P is needed alongside N, MAP or DAP carry both, reducing the total kg applied. Compound NPKs like 12-12-17 cover all three but at a lower percentage of any single nutrient.

Mixed grades exist for specific stages. **Pre-bloom**: high-P starters like 10-50-10 promote root + flower-bud development. **Vegetative**: balanced 20-20-20 + trace elements. **Fruit-set**: high-K like 13-0-46 (KNO3) for cell wall thickening + sugar transport. **Pre-harvest**: zero-N to avoid late vegetative flush + draw down nitrate residues that would otherwise show up in fruit residues. The pure engine respects whatever stage the program is in and picks accordingly.

Micronutrients (Fe, Mn, Zn, Cu, B, Mo) appear separately on the product label, typically as percent of element (not oxide). Chelated forms (EDTA, EDDHA) cost more but stay soluble at high pH where uncomplexed metals precipitate; in WiseYield's seed library Fe-EDDHA is flagged for pH-7.5+ soils where standard FeSO4 would lock up. Boron has the narrowest margin of any nutrient — 0.5 ppm deficient, 1 ppm optimal, 2 ppm toxic — so the engine never auto-adds B without an explicit program target.