Full explanation
Classic foliar mixes at BBCH 30–32 on winter wheat: 5–15 kg/ha urea + 0.5–1 kg/ha MgSO₄ + micronutrients (B-Cu-Mn, 0.3–0.8 L/ha). On sunflower at 4–6 leaf stage: B+Zn+Mo in chelated form. On corn V4–V8: Zn+Mn. Important: solution concentration <5% for most crops — higher causes leaf burn. Spray volume 200–300 L/ha ground, 20–40 L/ha drone. Air temperature <25°C, no direct sun (evening is best). Don't spray in drought without evening cooling — effective uptake drops to 20%. Trade-off: foliar feeding is tactical, not strategic. Saves yield under stress but doesn't replace balanced NPK. For routine farm maintenance on chernozems — not critical; for emergency deficiency correction (Fe chlorosis, B deficiency on sunflower) — mandatory.