Frequently Asked Questions
How do I calculate mixing rate per tank load?
Divide the total product needed for your farm by the number of tank loads. For example, if you need 4 litres for 2 ha and require 25 knapsack tank loads, you add 160 mL per 16-litre tank (4,000 mL ÷ 25 loads = 160 mL/tank). This calculator does that math for you automatically.
How many litres of water per hectare for a knapsack sprayer?
A standard 16-litre knapsack sprayer covers 200–300 litres per hectare, requiring 12–19 full tank loads. Walking speed and nozzle type affect this — slow walking means more water per ha. This calculator uses the midpoint (250 L/ha) by default but you can adjust it.
What does PHI (Pre-Harvest Interval) mean?
PHI is the minimum number of days that must pass between the last pesticide application and harvest. It ensures chemical residues break down to safe levels. Harvesting before the PHI is illegal in most countries and creates food safety risks.
Can I mix two pesticides in the same tank?
Only mix products that are labelled as compatible. Always perform a small jar test first — combine a small amount of each product in water and observe for 30 minutes. If the mixture separates, curdles, heats up, or forms a gel, do not mix them. Apply separately when in doubt.
Why is it important not to overdose on pesticides?
Overdosing wastes money, can damage crops (phytotoxicity), accelerates resistance development in pest populations, harms beneficial insects (bees, spiders), pollutes soil and water, and leaves dangerous residues in food. Using the correct dosage is both safer and more cost-effective.
When is the best time of day to spray?
Early morning (6–9 AM) or late afternoon (4–6 PM) are ideal. Midday spraying should be avoided — heat causes rapid evaporation and can cause phytotoxicity, bees are active, and spray drift increases with thermals. Always check wind speed (below 15 km/h) and avoid rain forecasts within 2–6 hours depending on the product.