Which nozzle goes on the boom for this pass? Pick it from the label, not from whatever is already threaded onto the sprayer. That label names the target and the droplet size the product needs to work, and the nozzle type plus the size inside that type are what deliver those two things. Pressure, speed, and output per acre all get tuned to a choice that has already been made.
Colorado State University Extension's sprayer calibration guide compresses the whole thing into one sentence: the first step in calibration is to determine the correct nozzle type and size. Type first, size second. I keep that order in front of me when a pallet of tips shows up, because the pull is always toward the flow table and a number. Flat-fan tips carry broadcast passes and banding work with medium droplets. Hollow cones run smaller droplets and exist for the passes where the product has to reach inside a canopy. Two different jobs, and a sprayer does one of them per pass.
Read the Label Before You Pick a Tip
A label settles three things before hardware enters the conversation: where the product has to land (broadcast across the field or banded over the row), how it acts once it lands (contact, killing only what it touches, or systemic, moving inside the plant), and how much goes out per acre. Nozzle choice serves those three decisions, which is why choosing a tip first and reading the label afterward costs you a full recalibration. I write the target and the rate on one sheet of paper, carry that sheet to the nozzle table, and leave the catalog shut until the sheet is filled in.
One line worth underlining on that sheet is whether the labeled target sits inside the canopy or on the outer leaf surface. That fact alone decides which family of tip can do the job, and it gets missed when the jug on the shelf looks like every other jug. A contact herbicide aimed at weeds under a closed canopy is a different nozzle problem from a broadcast burndown over bare ground, even when the rate and carrier volume read the same.
Flat-Fan Tips for Broadcast and Banding Passes
Flat-fan tips are used for broadcast spraying of most herbicides and some insecticides where a medium droplet size is needed, and the same tip style is used for banding herbicides over the row. A flat-fan tip is chosen as part of a boom-wide broadcast pattern rather than for what one tip covers by itself.
When I set up a post-emerge herbicide pass over open ground, I reach for a flat fan before a hollow cone. The droplet size is the reason: medium sits in the middle between coverage and drift, and most broadcast herbicide work is built around it. That buys a wider operating window; it gives up reach into a closed canopy. That preference holds only while two things are true — the label calls for a medium droplet, and the target is a leaf surface the boom can see. Change either one and the preference is worth nothing.
Suppose a field gets a single post-emerge broadleaf pass in June, the rows have not closed, and the label asks for medium droplets. Flat fan is the default and there is no argument to have. Suppose the same field has closed over by the next pass and the label targets a contact product on tissue beneath the canopy. The flat fan is now the wrong tool, and the fact that it worked in June says nothing about the later pass.
Hollow Cone Tips Where the Canopy Blocks Coverage
Hollow cone tips produce smaller droplets, and they are the tips used for insecticides and contact herbicides that need to penetrate the canopy. A small droplet is the mechanism rather than a side effect. It carries less mass, follows air movement through gaps in the foliage, and lands deeper than a heavier drop that stops on the first leaf it meets.
Any contact product has to land on the surface it kills. Droplets parked on top of the canopy are not coverage, however wet the field looks from the cab door. That is the whole case for a hollow cone on closed rows: the target is a leaf underside or a stem in the lower part of the plant, and a medium droplet thrown from a flat fan will not reach it in useful quantity.
What this does not settle is an orifice size, a pressure, or a flow rate for that job. The calibration guide supports the link between tip family and target type; real numbers live in the manufacturer's table for the specific tip you buy, and inventing them here would just produce a confident wrong answer.
Pick the Size Inside the Type You Chose
With the type fixed, size is the second half of that same first step, and the order inside it matters. Size is the part of the choice that sets how much liquid the tip delivers. Calibration is the process of matching that delivery to the labeled rate at your ground speed and nozzle spacing.
A wrong size poisons everything downstream. You can measure output, time a pass, and check the pattern, and still be wrong, because every measurement was taken from a starting point that never matched the label. Measuring was fine; the anchor was not.
What works is to carry three numbers to the manufacturer's flow table — labeled carrier volume per acre, ground speed, and nozzle spacing on the boom — and read off the size that satisfies all three at once. If no row in the table fits, change speed or spacing and read again. Splitting the difference between two rows by arithmetic is how a sprayer ends up applying something nobody planned.
What I Check on the Boom Before Spraying
I walk the boom before the tank gets filled. The first thing I look at is the marking on each tip, type and size, read one at a time against the order sheet. I have noticed that a mixed boom is the most common leftover from a nozzle change: a few new tips where the old ones were worst, the rest left alone, and now two sizes feeding one manifold.
Then I check the orifice edge on every tip, looking for nicks, a fan that has lost its shape, a cone that is visibly deformed. Anything I find gets recorded and set aside until I can check it against the manual or replace it.
Last, I hold the label up against the boom and confirm the family matches the target, flat fan for broadcast or banding, hollow cone where the canopy has to be penetrated. I have found a set from the previous pass still threaded on more than once, and that is the quietest way to spray the right rate through the wrong tip. Pulled tips go into bins sorted by type and size, so the next change starts from a known set instead of a can of unknowns.
None of that is a measurement. Reading markings and looking at edges is not the same as checking flow or droplet size, and a visual pass down the boom does not replace calibration.
The Tradeoff Behind Every Nozzle Choice
Hollow cones buy coverage inside a canopy and charge for it in drift exposure. Smaller droplets stay airborne longer and travel further off target when wind catches them, which is the same property that lets them slip through foliage. Flat fans buy a medium droplet and a wider operating window and give up penetration. Once the rows close, inner leaves are not picking up a meaningful deposit from a boom-mounted flat fan.
Stating that trade plainly beats pretending one family wins. Any right answer tracks the target the label names and the state of the crop on the morning you spray, and it flips when either of those changes.
The calibration guide behind this article covers principles of tip selection and how to run a calibration. It carries no side-by-side comparison trials, no service life figures, no price rankings, and no measured yield response, so this article puts no number on any of them. A supplier who quotes one should be asked where it came from.
One last move is not finding the best tip in a catalog. It is reading the label for target and droplet, choosing the family that matches both, then taking rate, speed, and spacing to the manufacturer's flow table to fix the size. Do that and calibration stands on something. Skip it and every measurement you take is careful, precise, and anchored to the wrong tip.
