Spray tank mix
Product per tank and number of tank loads for a field, from label rate and spray volume.
Boom sprayers are often 400 to 2 000 L; a knapsack is usually 15 to 20 L.
Litres of mix per hectare from your calibration. Not sure? Use the calibration check below.
Concentration rates (mL/100 L) are common for orchards, vegetables and knapsack spraying.
Use the rate on the registered label for this crop and target. Never exceed it.
Calibration check: work out your spray volume
Catch one nozzle's output for one minute at spraying pressure, then enter it with the nozzle spacing and your driving speed. For a knapsack, use your swath width and walking speed.
Most booms are 0.5 m.
Tractors often spray at 6 to 10 km/h; walking pace is about 3 to 4 km/h.
Enter nozzle output, spacing and speed to see L/ha.
Enter tank size, spray volume, field area and the label rate to see your mix.
How this is calculated
Always follow the registered product label. Do not exceed label rates, and check the label for the crop, target, withholding period, re-entry interval, mixing order and protective equipment.
- Area per tank = tank size (L) ÷ spray volume (L/ha). A 600 L tank at 200 L/ha covers 3 ha.
- Product per tank, for a per-hectare label = label rate × area per tank. At 2 L/ha that is 2 × 3 = 6 L in each 600 L tank.
- Product per tank, for a mL per 100 L label = rate × tank size ÷ 100. At 150 mL/100 L, a 1 000 L tank takes 1 500 mL (1.5 L); a 16 L knapsack at 50 mL/100 L takes 8 mL.
- Total water = field area (ha) × spray volume (L/ha). Total product is the same share of product in every litre of mix, so a 10 ha field at 2 L/ha needs 20 L.
- Tank loads: total water ÷ tank size. The whole-number part is full tanks; the remainder is the final partial tank, which gets product in proportion (200 L of a 600 L tank gets a third of the product).
- Calibration check: spray volume (L/ha) = nozzle output (L/min) × 600 ÷ (nozzle spacing m × speed km/h). A nozzle giving 0.8 L/min at 0.5 m spacing and 8 km/h applies 0.8 × 600 ÷ (0.5 × 8) = 120 L/ha. For a knapsack, use swath width and walking speed.
Spray volume changes how much area a tank covers, not how much product goes on each hectare, so re-check your calibration whenever you change nozzles, pressure or speed.
Read the guide: Calibrating a knapsack or boom sprayer, step by step
Results are estimates for planning. Check product labels and local recommendations before you apply anything.