Seller disclosure: XES Netting sells bale net wrap. We do not sell mowers, mower-conditioners, swath kits, tedders, or rakes, and we earn nothing from any brand or price named below. Equipment prices are figures reported by working producers and are included to show order of magnitude, not as quotes.
Short answer: In most of the humid US, yes — a swath laid at 70–72% of cut width reaches 65% moisture in about 6–8 hours, versus 24 hours or more for a narrow windrow at 25–30% of cut width. But wide swath is not universally correct, and that is the part most guides skip. It backfires on wet or heavy ground, in the arid West where hay dries past the point you can rake it without shattering leaves, and whenever big tires mat a short crop into tracks the tedder cannot lift.
Almost everyone writing about this answers a different question than the one producers actually ask. "Does spreading hay wide dry it faster?" is settled — it does, and we cover why in detail in how to make dry hay faster, which walks through the leaf-stomata mechanism and a documented 30-hour cut-to-bale run.
This guide answers the harder question: how wide should your swath be, on this field, today? That means the actual comparison numbers, the four situations where spreading wide is the wrong call, what the equipment costs, and a decision table you can use at the field gate.
Why wide swath works (the short version)
One paragraph of mechanism, because you need it to understand the exceptions later.
A cut forage plant is not dead. For the first several hours it keeps operating its stomata — the pores on the underside of the leaves — and those pores stay open in daylight and close in the dark. Spread the crop out and the leaves keep actively venting moisture. Rope it into a windrow and most of the crop mass sits in the dark, the pores shut, and the remaining water has to leave by slow diffusion through the stem instead. Our guide to making dry hay faster covers this mechanism and the tedding sequence in full.
Two consequences of that are worth stating here because they are routinely misunderstood:
- Conditioning does not substitute for swath width. Rollers and flails crack the stem cuticle to help moisture escape later in the cure. They do nothing about stomata. If you crimp aggressively and then drop the crop into a tight rope, you have optimized the wrong stage.
- Slow drying quietly costs you feed value. A plant that is still respiring is burning its own soluble sugars — exactly the fraction that makes hay palatable and energy-dense. Slow dry-down typically costs 2–8% of dry matter to respiration alone. It never shows up on the moisture meter and never shows up in the bale count.
What the research actually measured
The forage research on this is well established, most prominently from Dan Undersander's work at the University of Wisconsin. The headline findings:
- A swath laid at 70–72% of the mower's cut width reaches 65% moisture in roughly 6–8 hours.
- The same crop in a conventional narrow windrow at 25–30% of cut width takes 24 hours or more to hit the same point.
- Getting all the way to dry-hay moisture (~20%) takes about one day in a wide swath versus two to three days in a narrow windrow.
That last line is the one with money attached. The difference between a one-day cure and a three-day cure is not 48 hours of patience — it is whether you need a three-day clear forecast or a one-day clear forecast. In most of the eastern half of the continental US, three-day windows are the scarce resource.
You can read the extension treatment at the University of Wisconsin forage production program and a practical summary at MSU Extension on wide-swath haymaking.
Producers report the same magnitude. One operator running a center-pull Kuhn that lays down close to full cut width:
"My moco dries hay a full day quicker then rollers/windrows, and saves me from tedding, don't see the need as it's already spread out. […] 2015 didn't need it, 2016 it saved a lot of my hay from being sold as feeder."
— BCRick, HayTalk thread 55522
And an operator who simply removed the swath-forming shields from his discbine entirely, leaving a swath at about 90% of cut width:
"I took the swath forming sheilds right off my kuhn discbine. Leaves a swath 90% of cut width. Wish I would have done it sooner. […] We have had one of the rainest summers in recent memory. I could cut the hay one day and be baling dry hay later in the afternoon the next day. With out spreading it wide I would be like everyone else and have 80% of my hay rained on. This year iam less than 20%."
— hog987, HayTalk thread 55522
Going from 80% of the crop rained on to under 20% in a wet year is not a marginal gain. That is the difference between horse hay and feeder hay across an entire operation.
The humidity rule that tells you when to rake
Faster drying only pays if you keep the leaves. The constraint on when you can touch the crop is relative humidity, and there is a field-usable ladder that maps ambient RH to hay moisture:
| Relative humidity next to the hay | Hay moisture will be at least | What you can do |
|---|---|---|
| 90% | 40%+ | Rake or ted with minimal leaf shatter |
| 70% | 18% | Near the top of the baling window |
| 65% | 16% | Good dry-hay baling |
| 55% | under 12% | Excessive leaf shatter — stop handling it |
Source: hay wilson in TX, HayTalk thread 14809.
The practical protocol that falls out of this table is the one experienced operators converge on independently: spread wide off the mower, leave it alone through the heat of the day, then rake at first light with dew on it and bale late morning.
One producer described exactly that sequence:
"I leave the hay spread wide from the discbine(8ft-wide swaths), leave it to dry until it could be baled, then the next morning after the day it was dry enough to bale, I rake at 4-6am with the dew to keep the leaves on. I then bale late morning/early afternoon. Hay is green because only half has been exposed to the sun for more than a few hours, and full of leaves with little stem moisture."
— JoshA, HayTalk thread 14809
Note the secondary benefit he identifies: raking late means only the top half of the crop ever saw extended direct sun, so the hay keeps its color. Wide swath plus a late rake gets you fast drying and green hay, which is the combination people assume they have to trade between. More on the handling side in our rake selection guide and merger vs rake vs inverter comparison.
Predicting dry-down before you cut
Swath width interacts with yield. A heavy crop spread wide can still cure faster than a light crop in a rope, and you can estimate this in advance using pan evaporation — the daily evaporation rate your regional weather service reports.
The rough figures: the arid and southern US often runs about 0.40 inches of pan evaporation per day, while northern-tier areas near the Canadian border are closer to 0.20 inches. Total pan evaporation required to take a crop from 80% down to 20% moisture varies enormously with how much ground the crop covers:
| Yield | 100% ground covered (full-width swath) |
50% covered | 25% covered (windrow) |
10% covered (tight windrow) |
|---|---|---|---|---|
| 0.9 ton/acre | 0.30" | 0.41" | 0.62" | 0.72" |
| 1.5 ton/acre | 0.39" | 0.59" | 0.89" | 1.38" |
| 2.1 ton/acre | 0.51" | 0.79" | 1.07" | 1.97" |
| 2.5 ton/acre | 0.58" | 0.87" | 1.28" | 2.35" |
Source: pan evaporation table posted by hay wilson in TX, HayTalk thread 14809.
Work an example. A 2.5 ton/acre crop in a northern region running 0.20" of pan evaporation per day: at full width it needs 0.58" ÷ 0.20 ≈ 3 days. In a tight windrow it needs 2.35" ÷ 0.20 ≈ 12 days. That is not a refinement — that is the difference between making hay and watching it rot.
Notice also that the penalty for narrow windrows grows non-linearly with yield. At 0.9 ton/acre a tight windrow costs you 2.4× the drying power of full width. At 2.5 ton/acre it costs you 4×. The heavier your crop, the more wide swath matters.
Four situations where wide swath is the wrong call
This is the part missing from most articles on the subject, and it is why blanket advice fails. Wide swath has four well-documented failure modes.
1. Wet or heavy ground
If the soil surface is wet, laying the crop flat on it means the bottom of the swath is in contact with a moisture source all day. Narrow windrows leave bare ground between rows that can dry first, so when you finally do spread or rake, you are moving hay onto dry soil.
"One of my fields laid for 5 days in narrow rows, ground was still sticky to wet after those five days, tedded it, tedded again, wasn't drying out […] raked and baled then wrapped on the seventh day, ground was still wet and so was the hay.
The next 50 acres i made was on much lighter soils that after a few days after mowing had dust from driving across it […] The lighter ground was under 18% days before I got tired of messing with the heavier soil."
— mlappin, HayTalk thread 55522
Same weather, two miles apart, seven days versus under 18% — driven entirely by soil type. Soil texture and drainage are a bigger variable than swath width on heavy ground.
2. Tire tracks that mat the swath
When the swath is wider than your tractor's wheel track, you drive on your own hay. That compressed strip does not behave like the rest of the swath, and it creates two downstream problems:
"My only complaint is sometimes I have trouble getting the tedder to lift the matted tire track portion. In long hay its ok but in shorter stuff it can be hard without setting the tedder so aggressive it grabs dirt."
— slowzuki, HayTalk thread 55522
"I agree on the later cuttings the tedder wouldn't pick it up. Then you rakked it just a couple hours before baling and the rake pulls out of the tire tracks and you have that green hay mixed in there at 110% moisture when the rest is almost dry."
— endrow, HayTalk thread 55522
That second one is the dangerous failure. Wet green hay folded into an otherwise dry bale at the last moment is how you get a hot spot in a stack that reads fine on a probe. Big tires on a short crop make this worse — one producer specifically flagged 20.8x38 tires on a 120 hp tractor as the problem case.
3. The arid West
In low-humidity regions the constraint is not getting hay dry, it is keeping it intact long enough to bale.
"In parts of the arid west it is counter productive to lay out a wide swath. The hay becomes too dry too quick and there is not enough humidity to rake the hay when it is dry. In Arid conditions there is no NEED for solar power to dry the hay. Some hay growers have to add moisture to their windrows to retain the leaves during baling."
— hay wilson in TX, HayTalk thread 14809
Look back at the RH table: if ambient humidity never climbs above 55% even overnight, there is no window in which you can rake without excessive shatter. Accelerating dry-down in that environment makes the leaf-retention problem worse, not better.
4. When your drying power is wind, not sun
A subtle but important distinction:
"If you get the majority of your drying power from the sun, then the wider the better. But if you get it from the wind/air, then a tall narrow windrow may be better suited."
— JoshA, HayTalk thread 14809
A tall, fluffy windrow presents a large surface to moving air and lets wind pass through it. Under persistent overcast with a steady breeze, that can beat a flat mat that the wind blows over rather than through. As the same producer put it elsewhere in the thread: if the sun is not shining, wide or narrow is of little matter.
What it costs to go wide
Three routes, in ascending order of cost:
- Free — open the swath boards you already have. Most mower-conditioners have adjustable swath-forming shields. Many operators simply run them at maximum width by default and narrow them only when rain is expected that evening.
- Free, with commitment — remove the swath-forming shields. The producer quoted earlier took them off a Kuhn discbine entirely and got a swath at about 90% of cut width. This is reversible but you are storing parts in the shop.
- Aftermarket kit — roughly $144 was quoted from Hygrade Engineering for a 13-foot mower.
- Factory kit — roughly $400 for a Krone mower ordered with the wide-swath option from the dealer.
The payback arithmetic that one producer used to talk himself into it is worth reproducing, because it is the correct way to frame the decision:
"If you do the math, it only takes a couple kicker wagons(at roughly 200 bales each) to lose $1/bale in quality because the hay needed just a touch more sun before baling that we never got, to pay for a wide swath kit that cost roughly $400."
— Brncntry112, HayTalk thread 55522
400 bales at $1 of lost quality pays for the kit once. Against a machine you will own for fifteen years, this is close to a rounding error — which is why the honest recommendation is usually "get the capability and use it selectively," not "always spread wide."
One more variable that costs nothing and is routinely ignored: cutting height. Leaving 3–4 inches of stubble holds the swath up off the soil, lets air move underneath it, and keeps the rake from picking up dirt. Scalping the field and laying the crop directly on damp ground undoes most of what a wide swath buys you.
The decision tree
The best summary of how this actually gets decided in practice came from a producer describing his own inconsistency as a feature rather than a flaw:
"Hay making is 1/2 art, 1/2 science, 1/2 luck! (Government math)
Sometimes I mow, spread it wide, and don't ted. Ground needs to dry-ish, crop moderate to thin.
Sometimes I mow, dump it in a narrow windrow and ted. Ground is usually wet-ish, crop moderate to thick.
Sometimes I mow, spread it wide and ted. Ground ry-ish, crop thick. […]
Sometimes I mow it into a tall, narrow windrow and don't ted. Ground is dry, crop moderate to thin and lots of breeze and sun. Keeps the color.
I can't say I ever do the same thing twice--that's the art part. […] Balancing ground moisture, crop density and drying forecast is a decision tree--that's the science part."
— rjmoses (Ralph), HayTalk thread 55522
Condensed into a table:
| Ground | Crop | Conditions | Do this |
|---|---|---|---|
| Dry | Thin to moderate | Sun | Spread wide, no tedding |
| Dry | Thick | Sun | Spread wide, then ted |
| Wet or heavy | Moderate to thick | Any | Narrow windrow, let ground dry, then ted |
| Dry | Thin to moderate | Overcast + steady wind | Tall narrow windrow, no tedding — keeps color |
| Any | Any | Rain expected that evening | Narrow it up — a tight windrow sheds better |
| Any | Any | Arid, RH never above 55% | Narrow — protect leaves, not speed |
The meta-lesson: the value of a wide-swath capability is optionality. You are not buying a setting you will use every day. You are buying the ability to match the swath to today's ground, today's crop, and today's forecast. If you want to go deeper on accelerating cure, see how to make dry hay faster and our hay tedder guide.
What this has to do with net wrap
Directly: swath width determines the moisture you bale at, and moisture at baling determines what your binding has to survive.
Two specific interactions worth knowing:
- Uneven dry-down produces uneven bales. The tire-track problem described above puts wet green hay into an otherwise dry bale. Those bales heat, settle, and change shape in the stack — and a bale that changes shape puts uneven tension on the wrap, which is a common cause of net that looks fine on the day and is loose by November. Our guide on round bales not holding shape covers the diagnosis.
- Faster cure means fewer compromise bales. Every day of exposure is another chance to get rained on and another decision about whether to bale marginal-moisture hay. Wide swath, used when conditions suit it, mostly removes that decision. When you do have to bale wetter than you wanted, baling moisture for net-wrapped bales covers the thresholds.
Net wrap does not fix a drying problem. It determines how much of a good cure survives storage. Shop XES net wrap →
The bottom line
Hay dries faster in a wide swath because sunlight holds the leaf stomata open and a windrow's dark interior shuts them. That is a biological mechanism, not a surface-area argument, and it is why the effect is large — 6 to 8 hours to 65% moisture at 70–72% of cut width, versus 24 hours or more in a narrow windrow.
But the correct swath width is a function of your soil, your crop density, your humidity, and today's forecast. On wet ground, in the arid West, or when a short crop is getting matted under big tires, narrow is the right answer and spreading wide will cost you.
Buy the capability — it runs from free to about $400 — and then use the decision tree rather than a rule. The producers getting the most out of this are not the ones who always spread wide. They are the ones who can do either, and choose.
Frequently asked questions
Does hay dry faster in a swath or a windrow?
Hay dries substantially faster in a wide swath in most humid regions. Research shows a swath laid at 70 to 72 percent of cut width reaches 65 percent moisture in 6 to 8 hours, while a narrow windrow at 25 to 30 percent of cut width takes 24 hours or more. The difference is largest on heavy crops.
How wide should a hay swath be?
Aim for 70 to 72 percent of your mower's cut width for fast drying in humid regions, which research shows reaches 65 percent moisture in 6 to 8 hours. Some operators remove the swath-forming shields entirely for roughly 90 percent. Narrow to about your tractor's wheel track on wet ground or when rain is forecast.
When should you not use a wide swath?
Avoid wide swath on wet or heavy ground, where narrow windrows let the soil between rows dry first. Avoid it in arid regions where humidity never rises enough to rake without shattering leaves. Narrow up when rain is forecast that evening, and reconsider when big tires mat a short crop into tracks the tedder cannot lift.
How much does a wide swath kit cost?
Costs range from nothing to about $400. Many mower-conditioners simply have adjustable swath boards you can open to maximum width, and some operators remove the swath-forming shields entirely for roughly 90 percent of cut width. An aftermarket kit was quoted around $144 for a 13-foot mower, and a factory Krone option around $400.
What is the best time to rake hay to keep the leaves on?
Rake at first light while dew is still present. At 90 percent relative humidity the hay will be at least 40 percent moisture and can be raked or tedded with minimal leaf shatter. Below 55 percent humidity the hay drops under 12 percent moisture and shatters excessively, so stop handling it in mid-afternoon dry conditions.
Written by the XES Netting team. We manufacture bale net wrap and read the farmer forums so the people doing the work can find clear, source-cited answers faster. Every quote in this post is verbatim with a source link — go read the originals.
Hero image: Freshly mown hay swaths and windrows on a mowed field by Santeri Viinamäki on Wikimedia Commons, used under CC BY-SA 4.0.
