The nozzle is the cheapest part of a sprayer and the one that decides whether the spray does its job. It controls droplet size, spray pattern and flow rate. Change the nozzle and you change how much chemical lands on the leaf, how much drifts away and how much runs off onto the soil.
Here is what the common types do.
Flat fan
Produces a flat, fan-shaped sheet of spray with even distribution across its width. This is the standard choice for boom spraying on field crops, especially for herbicides, where you want uniform coverage of the ground and the least possible drift.
Overlap matters with flat fans. Adjacent nozzles on a boom must be spaced and set at a height that lets their patterns overlap correctly, or you get striping in the field.
Hollow cone
Throws a ring-shaped pattern of fine droplets. Fine droplets mean better coverage of leaf surfaces, including undersides, which is why hollow cone nozzles are the usual choice for insecticides and fungicides where contact with the pest or the pathogen is what counts.
The trade-off is drift. Fine droplets travel, so hollow cone work should be done in calm conditions.
Full cone
Fills the whole circle rather than just the ring, with larger droplets than a hollow cone. Used where you want heavier, more penetrating coverage — soil application, drenching, and some tree work.
Flood or deflector
Spray hits a flat surface and spreads into a wide, coarse fan. Large droplets, low drift, high flow. Used for fertiliser application and for band spraying where precision matters less than getting volume down.
Adjustable and multi-nozzle guns
Most spray guns sold with HTP sprayers let you turn the tip to move between a narrow jet and a wide cone. A narrow jet carries further, which is how you reach the top of a tall tree; a wide cone covers more area at short range.
Double and triple nozzle heads let one operator cover more rows per pass, but remember that every extra nozzle divides the available flow. Adding nozzles without enough pump capacity simply drops the pressure at each one. Our spray guns and nozzles section lists the patterns available.
Pressure changes everything
The same nozzle behaves differently at different pressures. Raise the pressure and droplets get smaller, coverage improves and drift risk rises. Lower it and droplets get coarser and heavier.
This is why chasing maximum pressure is a mistake. Set the pressure the chemical label recommends, then choose the nozzle that gives the right pattern at that pressure — not the other way round.
When to replace a nozzle
Nozzles wear from the inside out. As the orifice erodes, flow increases and the pattern degrades, so you are applying more chemical than you think while getting worse coverage. Brass wears fastest, stainless steel and ceramic last longest.
A simple field check: spray into a measuring jug for one minute at your normal working pressure and compare with the nozzle's rated output. If flow has risen roughly ten per cent above rated, replace it. Also replace any nozzle whose pattern looks uneven, streaky or split.
Never clear a blocked nozzle with wire or a pin. It will damage the orifice permanently. Soak it and use a soft brush or compressed air instead.
Small habits that pay
- Keep a spare set of the nozzles you use most — they are inexpensive and a blocked nozzle should never stop a spray day.
- Use one nozzle type per tank, not a mix, or your application rate is guesswork.
- Flush the whole line with clean water after every job, including the gun and hose.
- Check the pump spare parts at the same time. Worn seals show up as pressure loss that people often blame on the nozzle.