Free orchard spray calculator. Enter trees to find the total spray volume and the concentrate you need for one orchard spraying round.
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Enter the number of trees. This calculator plans 5 litres of spray per tree and 10 ml of concentrate per litre of spray, so 10 trees need 50 litres of spray and 500 ml of concentrate. It is a planning estimate only: always follow the product label rate, and use the tree row volume sections below to check whether your trees need more or less than the planning figure.
Spray volume per tree in this calculator is 5 litres, and concentrate is 10 ml per litre of spray. For 10 trees that gives 50 litres of spray and 500 ml of concentrate, and for 3 trees it gives 15 litres and 150 ml. Real orchards vary by tree size, canopy density and sprayer type, so treat 5 litres as a planning middle for a medium tree, not as a label rate. Many growers start with this figure and then adjust it for their own block.
Tree row volume, or TRV, is the volume of water needed to spray a canopy to the drip point. The extension formula is TRV equals tree height times tree width times 43560 times 0.7, divided by row spacing times 1000, with height, width and spacing in feet. A mature tall spindle orchard at 11 feet high, 7 feet wide and 12 feet row spacing gives about 196 gallons per acre, rounded to 200 gallons per acre.
Extension guides define dilute, or high volume, spray as 350 to 800 gallons per acre, semi concentrate as 100 to 350 gallons per acre, and concentrate, or low volume, spray as 10 to 100 gallons per acre. If you spray less water than the full dilute volume, you must concentrate the chemical in the tank by the same factor, so the amount of product per acre stays the same. Oil and surfactant products are the exception and are usually not concentrated.
A sprayer calibration worksheet works block by block: first calculate dilute gallons per acre from tree row volume, then divide by the concentration factor to get gallons per acre to apply, then work out gallons per minute from travel speed and row spacing. The UMass worksheet formula for gallons per minute is gallons per acre times travel speed in miles per hour times row spacing in feet, divided by 495. Calibrate on each block that differs in tree size, shape or age.
Work out spray volume first, then concentrate. For a 500 litre tank at 5 litres per tree, the tank covers 100 trees. At 10 ml of concentrate per litre, that tank needs 5000 ml, or 5 litres, of concentrate. For a partial tank, multiply the litres you will actually spray by the concentrate per litre. Always add concentrate to a partly filled tank, then top up with water, and agitate while spraying.
Young trees need much less spray than mature trees because their canopy is smaller. Extension notes put young tall spindle blocks near 100 to 150 gallons per acre, mature tall spindle blocks near 200 gallons per acre, and cap the planning figure at 200 gallons per acre even for older, larger trees, since larger trees thin more easily. Early season trees at green tip have only a fraction of their full leaf area, so early sprays need less volume than full canopy sprays.
Coverage to the drip point means the canopy is wet right up to the point where spray starts to drip off the leaves. That is the full dilute standard, and low volume sprays deliberately stop short of it with fine droplets instead. Whichever volume you use, the pesticide label rate always rules: never exceed the label rate, wear the protective equipment the label lists, and never use this calculator as a substitute for the label. If the label and this page disagree, follow the label.
This calculator plans 5 litres per medium tree. Small young trees need less and large mature trees need more, so check tree row volume for your block.
Tree row volume is the water volume needed to spray a canopy to the drip point, calculated from tree height, tree width, row spacing and a 0.7 density factor.
Use TRV equals height times width times 43560 times 0.7, divided by row spacing times 1000, with all lengths in feet. A mature tall spindle block works out near 200 gallons per acre.
The concentration factor is full dilute volume divided by the volume you actually spray. Spraying half the dilute volume is a 2X application, so the tank concentration doubles.
Multiply spray litres by concentrate per litre. At 10 ml per litre, a 50 litre mix needs 500 ml of concentrate. Always check the product label for the real rate.
Yes. Young trees with a small canopy need far less volume than mature trees, and early season trees need less again before full leaf.
It means the canopy is wet to the point where spray just starts to drip off the leaves. It is the standard for a full dilute spray.
Always follow the label. This calculator is a planning estimate only and never overrides a product label rate or safety instruction.