The tractor pulls both labourers forward at one steady speed, so both lances spend the same time at each tree. The litres each tree gets depend on that time. Time the 50 m with a labourer walking beside the tractor, holding a charged lance and hose, so the speed you enter is the speed you spray at.
The calculator needs a measured discharge in litres per minute. A lance that can be turned to any setting gives a different flow each time it is moved, so no single figure describes it. Use a fixed-output lance, or a lance with pre-set positions where you have measured the discharge at each position.
Trees aged 1 to 2 years are small enough for one lance to cover the whole canopy from one side. One side then gives a full dose, so the tractor drives every second inter-row. From 3 years the canopy is too large for that. Each side gets half a dose, and the tractor drives every inter-row.
At the start of every season, and whenever a lance, nozzle or hose changes. Also recalibrate when you change labourers, tractor gear or engine speed, or move to a block with a different tree age. Run the field check each time to confirm the result.
Need Help With Your Spray Programme?
Book a consultation and we will help you calibrate your lances and set up an effective spray programme for your orchard.
Use fixed-output lances, or lances with pre-set positions
Do not use a lance that turns freely to any setting
Use clean water
Set the regulator to your working pressure
Calibrate in the block you will spray
Farm Details
Enter your farm name and field/block number. These appear on the printed report for your records.
Measuring Discharge at Each Lance Position
What you need: Bucket, measuring jug or bottle with marks, stopwatch or phone timer.
What to do:
Fill the tank with clean water and run the pump at working pressure
Hold the bucket under Lance A
Spray into the bucket for 60 seconds
Measure how many litres are in the bucket
Repeat for every position on Lance A
Do the same for every position on Lance B
Enter each result in the positions table for that lance
Choose the position you will spray with under “Position used for this calibration”
Example: If you collect 2.4 litres in 60 seconds, enter 2.4. A fixed lance has one position, called “Fixed”.
Timing Speed
What you need: Rope or tape, stopwatch or phone.
What to do:
Measure 50 metres in the inter-row
Mark start and finish
Drive the tractor at spraying speed in the gear and engine speed you will use
Have a labourer walk beside it, holding a charged lance and hose
Time how many seconds it takes
Enter the seconds under “Seconds to Walk 50 m”
The tractor sets the pace for both labourers. The calculator shows your speed as you type.
Choosing the Spray Method
Continuous — the lance sprays without stopping along the row. Use it when canopies touch or nearly touch.
At each tree — the lance sprays only while passing a tree canopy. Enter the canopy width along the row. If the canopy width is more than the tree spacing, the calculator uses the continuous method.
Speed Guidance by Tree Age
Tree age
Speed (km/h)
1–2 years
approx. 3.5
3–4 years
2.5–3.0
5–7 years
2.0–2.5
Over 7 years
1.5–2.0
This is guidance only. The calculator still works at other speeds, but shows an amber note when you are outside the range for the tree age.
How Tree Age Changes the Dose
Trees aged 1–2 years take a full dose from one side. Spray every second inter-row.
Trees aged 3 years and older take half a dose from each side. Spray every inter-row.
Product & Tank
Tank Capacity — your spray tank size in litres
Product Name — for your reference in the results and printed report
Product Rate — the label rate in L/ha or kg/ha
Product Rate per Tree — optional. Enter mL or g per tree if the label gives a rate per tree. This rate is then used for product per tank.
Always follow the product label. The calculator converts the label rate into the correct amount for your tank based on the actual lance output.
Reading the Results
After pressing Calculate, the results bar shows:
Speed — your spraying speed in km/h, with a green or amber note for the tree age
Litres per Tree Side — what Lance A and Lance B each put on one side of a tree
Lance Imbalance — how far apart the two lances are. More than 10% shows an amber warning.
Litres per Full Tree — the total spray each tree receives
Water Volume — litres per hectare of orchard
Product per Tank — how much product to add, with the trees and hectares one tank covers
Pass Pattern — whether to spray every inter-row or every second inter-row
Mixing Order (Very Important)
Fill tank 70% with clean water
Measure product in a bucket
Add product into tank while mixing
Add humic or seaweed products
Add microbes last
Top up with water to full tank
Spray the same day
⚠️ Do not store mixed product overnight
Check Your Calibration (Field Test)
Continuous method:
Spray a 100 m pass with both lances
Measure the litres used by both lances together
Area sprayed (ha) = 100 × row spacing × k ÷ 10 000, where k is 2 for trees aged 1–2 years and 1 for older trees
L/ha = litres used ÷ area. Compare with the calculator.
At each tree method:
Spray 20 trees on each side of the tractor (40 tree sides, both lances running)
Measure the total litres used
Litres per tree side = litres used ÷ 40. Compare with the calculator.
If your result is within ±10% of the calculator result, your calibration is correct. The printed report has a box for writing in your field check.
Important Tips
Recalibrate when a lance, nozzle or hose changes
Use the same labourers you calibrated with
Keep the tractor in the same gear and engine speed for each age band
Check both lances. If they differ by more than 10%, check the nozzle, hose or position setting before spraying.
