Hay Leaf Shatter: Where Your Leaves Actually Go — and How to Keep Them

By the XES Netting team — bale net-wrap manufacturer · Updated August 23, 2026 · ~13 min read

Every hay producer has had the same moment. You look back from the tractor seat at a baler working good alfalfa, and you can see a green cloud coming off the pickup. One producer described it on a forum thread about where leaf shatter actually happens, in a way a lot of people recognized instantly:

You start losing leaves as soon as the pickup tine touches the hay. From the can you can see the leaves flying off. Makes you wanna cry.

— rank, HayTalk, "Where does leaf shatter occur?"

The instinct after watching that is to blame the machine. It is almost always the wrong instinct. Hay leaf shatter is a moisture problem that your equipment reveals rather than causes, and the producers who fix it do not fix it by buying a different baler. This guide lays out where the leaves actually go, measured operation by operation, what the real control variable is, and which of the decisions in front of you are worth anything.

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Why leaf loss costs more than it looks like it should

Leaves and stems are not the same feed. The leaf carries the protein and most of the digestible energy; the stem carries the fiber. So a percentage of leaf lost is never just that percentage of tonnage lost — it is a disproportionate share of the quality you were selling.

The published figures make that concrete. In the loss table compiled by C. Alan Rotz and Richard Muck and reproduced by New Mexico State University Extension in Circular 668, Reducing Harvest and Post-Harvest Losses of Alfalfa and Other Hay, round baling averages 6% dry-matter loss — and that same 6% carries a 1.7 percentage-point drop in crude protein and a 3.0 point rise in NDF. Tedding averages a 3% dry-matter loss but only a 0.5 point protein drop. The dry matter you lose at the baler is worth considerably more per pound than the dry matter you lose earlier.

That is also why the loss is so visible and so demoralising. A producer selling on appearance explained exactly what it looks like when the window has been missed:

If it's too dry, when a guy walks behind the baler, every time the bale makes a new flake, the leaves just fall to the ground as dust.

If you walk to the pickup area of the baler, as the pickup is lifting the hay, you see the leaves go in all directions. …

— Rodney R, HayTalk, "Where does leaf shatter occur?"

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Where the leaves actually go: a loss budget

The single most useful thing you can do with leaf loss is stop treating it as one event and start treating it as a running total. Every operation between the standing crop and the stack takes a cut. Here is the published budget, from the Rotz and Muck table in NMSU Circular 668.

Dry-matter losses and nutritive-value changes during alfalfa harvest, adapted from Rotz & Muck (1994) and Rotz (2005), as tabulated in NMSU Extension Circular 668.

Two things jump out of that table that most people never notice.

First, the ranges matter far more than the averages. Raking averages 5% but spans 1% to 20%. That twenty-fold spread is not twenty different rakes — it is the same rake run at different crop moistures. The average is almost meaningless as a planning number; what it tells you is that raking is the operation with the most upside from doing it right and the most downside from doing it wrong.

Second, swath inversion is the cheapest handling pass in the entire table. It averages 1% dry-matter loss and, uniquely, shows zero change in crude protein, NDF and digestible dry matter. Every other handling operation degrades the feed. Inverting does not. NMSU states it plainly: swath inversion results in lower losses than tedding and raking and does not affect nutritive value. If you have been treating an inverter as a curiosity, that line is the argument for it — and we go deeper on that trade-off in our merger vs rake vs inverter comparison.

Producers arrive at the same running-total logic from the other direction. On the same HayTalk thread, rank added up his own chain:

...and this is just from baling. Factor in one or two tedd jobs + one or two rake jobs at a MINIMUM of 10% leaf loss per and you start to see why wet hay is attractive.

— rank, HayTalk, "Where does leaf shatter occur?"

His 10%-per-operation figure sits at the pessimistic end of the published ranges rather than the average, which is what you would expect from someone working dry western hay. A Texas producer put his whole-system number in the same territory:

I have long assumed a 20% drymatter losse from standing hay to baled hay in the barn. Maybe that is a little conservative when handling hay with a less than 40% humidity.

— hay wilson in TX, HayTalk, "An observation on leaf shatter"

Twenty percent from standing crop to barn is entirely consistent with the table once you stack four or five operations. That is the number worth carrying in your head.

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The root cause: leaves and stems dry at different speeds

Here is the mechanism that explains everything else. A cut alfalfa plant does not dry as one object. The leaf is thin, has a large surface area relative to its mass, and loses water quickly. The stem is thick, waxy and full of water, and gives it up slowly — which is the entire reason conditioners exist.

So the two halves of the plant are almost never at the same moisture at the same time. And critically, the number on your moisture meter is an average of the two. A Texas producer explained the arithmetic better than most extension bulletins do:

Stems at 10% moisture and leaves at 30% moisture will average 20% moisture and not have significant leaf loss.

— hay wilson in TX, HayTalk, "Where does leaf shatter occur?"

Read that carefully, because it inverts the usual advice. Two bales can both read 20% on the tester. One has wet stems and dry leaves and will shatter. The other has dry stems and rehydrated leaves and will bale beautifully. The average tells you about spoilage risk. It tells you almost nothing about leaf retention.

This is why night and dew baling works at all: the stem stays dry while the leaf pulls moisture back out of the air. It is not that the hay got wetter — it is that the moisture went back into the part of the plant that needed it. Our guide to baling hay on the dew covers how to run that window in practice.

The experiment that proves the machine is not the problem

If you still suspect your baler, one producer ran the cleanest possible test. He removed every machine from the equation except the baler itself — no conditioner, no tedder, no rake, one single pass:

No conditioning, no raking. Just went out and picked up the mower swath with the baler. Still ended up with no leaves in the bale. What the pickup didn't knock off made it through the baler and fell off the end of baler chute.

— gregorydepuydt500, HayTalk, "Alfalfa leaf shatter!"

One pass, minimum possible handling, and the leaves still ended up on the ground. That result is impossible to explain with a machine theory and trivial to explain with a moisture theory. An experienced producer on a separate thread had already reached the same conclusion about where the responsibility sits:

In the end - I still think all balers are somewhat violant in delivering hay to the bale chamber. IMHO - leaf loss is more of a function of hay conditioning and dryness prior to baling.

— VA Haymaker, HayTalk, "Small square balers and leaf loss"

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Relative humidity is the control variable

Crop moisture is what you want to manage, but you cannot dial it. Relative humidity is what you can actually watch, and it drives leaf moisture directly. What is striking is how tightly independent operators in different climates converge on the same range.

Two producers on opposite sides of the planet, in completely different climates, landing within a few points of each other is about as good as field consensus gets. Here is the Iowa version, with the caveat that makes it useful:

Leaf shatter can be avoided by raking or baling when the free air humidity is in the 65% range. Then the leaves can tolerate handling without shatter. I tend to work with alfalfa at humidities less than that because at 65% the humidity is likely changing rapidly either up or down. The window of ideal conditions to handle alfalfa is usually very small.

— Gearclash, HayTalk, "Alfalfa leaf shatter!"

And the Australian version, which adds a field test you can do without any instrument at all:

I usually as a guide start baling when relative humidity hits 67-70% or when you squeeze a handful and the leaf doesn't shatter and knock off at 81-83% but that depends on many other parameters.

— Hunter Valley Lucerne, HayTalk, "Alfalfa leaf shatter!"

The squeeze test is the practical takeaway for anyone without a hygrometer on the tractor: grab a handful, squeeze, and watch whether the leaf comes off in your hand. If it does, the field is not ready.

Be realistic about how long that window lasts:

We have to wait until 10 pm to start baling. We usually have a 4 hr. window.

— NDVA HAYMAN, HayTalk, "Where does leaf shatter occur?"

Four hours. If your baling capacity cannot clear the acres you mowed inside a four-hour nightly window, no adjustment on the machine will save the leaves — the constraint is capacity, not setup.

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What actually reduces leaf loss, ranked

Working from both the published table and what operators report, here is the honest ranking.

1. Handle at the right moisture. Nothing else is close. This is the difference between raking at 1% loss and raking at 20%.

2. Eliminate a pass. Each operation you delete removes its whole line from the budget. Ted only when tedding earns its keep — our hay tedder guide covers when it does and when it costs you. Wide swaths often remove the need to ted at all; NMSU cites University of Wisconsin work in which swaths laid at 72% of cut width produced better-quality hay than swaths at 25%.

3. Substitute a gentler pass. If a pass cannot be deleted, inverting instead of raking swaps a 5% average operation for a 1% one with no nutritive penalty.

4. Make bigger windrows and spend less time in the chamber. This is where round baling has a genuine, underrated advantage, and one producer explained the mechanism precisely:

To save leaves I like Lg windrows also,the longer it takes to make the bale the more leaf loss you will have.Netwrap saves leaves also as it isnt turning 10 times to get the twine on vs 2.

— swmnhay, HayTalk, "Round vs large square leaf loss"

That is a real and often-missed mechanism. A finished round bale has to rotate inside the chamber for the entire time the binding is being applied. Twine needs many more revolutions than net wrap to cover the bale, and every one of those revolutions is the bale surface abrading against the belts or rollers with the leaves still on it. Fewer turns, less surface abrasion, more leaf retained. The same producer's summary was blunt: if your concerns are leaf shatter, net wrap.

5. Pick the bale package that lets you bale wettest. This one is counter-intuitive and worth thinking about carefully.

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Bale format changes the math in two directions

Reading the loss table alone, large rectangular bales look like the leaf-friendly choice: 3% average loss against 6% for large round. But that comparison is incomplete, because the two packages have different safe moisture ceilings.

NMSU gives the highest recommended baling moisture as roughly 18–20% for small rectangular bales, 16–18% for large round bales, and 12–14% for large square bales. Large squares are dense enough that trapped moisture cannot escape, so they have to be baled substantially drier — and "substantially drier" is precisely the condition that shatters leaves.

So the large square baler is the gentlest machine in the table but demands the most brittle crop, while the round baler is the roughest but lets you work four to six points wetter. Which one keeps more leaf on your farm depends on whether your limiting factor is the machine or the weather. In a humid climate with reliable dew, the round baler's wider moisture window can easily outweigh its higher mechanical loss. In an arid climate where you cannot get moisture back into the leaf at all, the gentler machine wins.

One useful piece of reassurance from a Texas producer, for anyone worrying about what happens after the bale is formed:

IMHO after hay is baled only surface of bale can loose leaves unless bale explodes

— Tx Jim, HayTalk, "An observation on leaf shatter"

That is right, and it is the reason binding choice matters beyond the chamber. Once the bale is tied, the leaves at risk are the ones on the surface — which is exactly the population that a bale losing its shape, sagging, or shedding its outer rind will surrender. This is the same mechanism behind the storage-loss numbers: the USDA Agricultural Research Service trial by K.J. Shinners and colleagues measured average outdoor dry-matter losses of 19.5% for sisal twine, 11.3% for plastic twine and 7.3% for net wrap across its trials. Our guide to storing net-wrapped bales outside covers what that does and does not buy you.

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The honest limits: what none of this fixes

Three things are worth stating plainly, because a guide that promises leaf loss is entirely solvable is lying to you.

Some leaf loss happens before you ever start the tractor. One producer on the leaf shatter thread pointed to black stem disease causing leaf drop in the standing crop, particularly on first- and second-year stands. If leaves are on the ground before mowing, harvest technique cannot recover them — that is an agronomy and variety problem.

Not every crop behaves like alfalfa. The assumption that alfalfa is the worst offender is not universal. On the "how much" thread, hay wilson in TX reported that bermudagrass shattered more than alfalfa in his conditions. Do not carry alfalfa rules unmodified into a grass crop.

The published averages are not your farm. Every figure in the tables above is a trial mean across specific crops, climates, machines and moistures. The 1–20% raking range exists because context dominates. Use these numbers to rank your decisions, not to forecast your tonnage.

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A leaf-saving field checklist

Print this, or keep it on the phone.

• Before mowing: lay the widest swath your mower and rake width allow. Wide swaths dry faster and often remove the need for a tedding pass entirely.
• Before each handling pass, ask: can I delete this? Every deleted pass is a whole line off the loss budget.
• Rake at 35–40% crop moisture, not by the clock. Too wet ropes the windrow and slows drying; too dry and you are inside the 20% loss end of the range.
• Do the squeeze test before committing the baler. Grab a handful, squeeze, and check whether leaf comes off in your hand.
• Watch RH at the windrow, not on the weather app. Humidity down at crop level is what the leaf responds to.
• Target roughly 65–70% RH as the point where alfalfa handles cleanly — and expect the window to be a few hours, not all night.
• Match capacity to the window. If you cannot clear the acreage in the hours available, reduce what you mow rather than baling outside the window.
• Build the biggest windrow the baler will take cleanly so the bale spends less time turning in the chamber.
• Use net wrap on round bales if leaf retention matters — fewer chamber revolutions to secure the bale, and a tighter surface afterwards.
• Walk behind the baler once per field. The leaf trail on the ground is the most honest instrument you own.

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Where XES fits

We manufacture bale net wrap, so treat this section as what it is. The leaf-retention argument for net wrap is genuine but narrow: it comes from the bale making two or three revolutions to be secured instead of ten or more, and from a tighter surface that holds the outer layer together afterwards. That is a real mechanism, described by producers who use both, and supported by the storage trial data above.

It is also not the main lever. If you are baling alfalfa at 40% relative humidity in the afternoon, no binding will save your leaves. Get the moisture window right first; the wrap is the last few percent, not the fix.

The honest cost note: NMSU points out that net wrapping carries a higher consumable cost than twine, and cites an increase in baling cost of up to 40% from the wrap itself in the work it references. That is precisely the number we exist to bring down — we sell factory-direct net wrap without the importer and distributor layers that normally sit between the extruder and the farm. Compare the full trade-off in our net wrap vs twine breakdown.

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Frequently asked questions

What causes leaf shatter in hay?

Leaf shatter is caused by handling alfalfa when the leaves are too dry and brittle. Leaves lose moisture much faster than stems, so by the time stems are safe to bale the leaves may already be brittle enough that any contact — pickup tines, rake teeth, tedder — knocks them off the stem.

At what relative humidity should you bale alfalfa to avoid leaf loss?

Producers across several climates independently target roughly 65–70% relative humidity measured at the windrow. Below about 60% RH, leaf loss rises sharply. A field check without instruments: squeeze a handful of hay, and if leaf breaks off in your hand, it is too dry to handle.

How much dry matter is lost between cutting and the barn?

Published averages are about 2% for mowing and conditioning, 3% for tedding, 5% for raking, and 3–6% for baling depending on the package. Stacked across a typical chain, total field loss commonly runs 10–20%, and experienced producers routinely assume around 20% from standing crop to barn.

Does net wrap reduce leaf loss compared to twine?

It helps, for a specific reason. A round bale must rotate in the chamber while it is being secured, and twine requires far more revolutions than net wrap. Fewer revolutions means less surface abrasion with leaves still attached. Net wrap also holds the bale surface tighter afterwards, protecting the outer layer.

Is a rake or a tedder worse for leaf loss?

Raking is the riskier operation. Published dry-matter losses average 3% for tedding versus 5% for raking, but raking spans 1–20% depending on crop moisture. Swath inversion is gentler than both, averaging 1% loss with no measured change in crude protein or fiber.

Can you avoid leaf loss with a better baler?

Not really. One producer removed the conditioner, tedder and rake entirely and baled the mower swath directly, and still lost the leaves. Leaf shatter tracks crop moisture at the time of handling far more closely than it tracks machine brand or condition.

Do large square bales lose fewer leaves than round bales?

The machine is gentler — 3% average loss versus 6% for round bales — but large squares must be baled at 12–14% moisture against 16–18% for round bales. That drier requirement can cost more leaf than the gentler machine saves, especially in arid conditions.

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The bottom line

Hay leaf shatter is not a machine defect and it is not bad luck. It is the predictable result of touching alfalfa when the leaf is drier than the stem, and it compounds with every pass you make. The producers who keep their leaves are not running special equipment — they are running fewer passes, inside a narrower moisture window, with enough capacity to finish before the window closes.

Start by counting your passes and pricing each one against the table above. Then work backwards from the four-hour window you actually have. If round baling is part of that plan, net wrap keeps the bale turning fewer times and holds the surface together afterwards — a small edge, honestly described, on top of decisions that matter more.

Sources: John Idowu, Kulbhushan Grover, Mark Marsalis and Leonard Lauriault, "Reducing Harvest and Post-Harvest Losses of Alfalfa and Other Hay," New Mexico State University Extension Circular 668 (pubs.nmsu.edu, accessed August 23, 2026), including the dry-matter loss table adapted from Rotz & Muck (1994) and Rotz (2005), baling moisture recommendations from Rotz & Muck (1994), Collins (1995) and Rotz (2003), mowing and conditioning loss estimates from Orloff & Mueller (2008), and wide-swath findings from Shinners & Herzmann (2006); K.J. Shinners, B.M. Huenink, R.E. Muck and K.A. Albrecht, "Storage Characteristics of Large Round Bales: Dry Hay," USDA Agricultural Research Service publication record (ars.usda.gov, accessed August 23, 2026); producer discussion on HayTalk threads "Where does leaf shatter occur?", "An observation on leaf shatter," "Alfalfa leaf shatter!", "Small square balers and leaf loss," and "Round vs large square leaf loss" (haytalk.com, accessed August 23, 2026). Dry-matter and nutritive-value losses vary widely with crop, climate, machine and moisture; published ranges are indicative, not predictions for a specific farm.

Related guides

• Baling hay on the dew — how to run the night window
• Hay tedder guide — when tedding pays and when it costs you leaves
• Rake selection guide — choosing the rake for your system
• Merger vs rake vs inverter — the gentler-pass options compared
• Net wrap vs twine — the full cost and performance trade-off
• Storing net-wrapped bales outside — protecting the surface leaves after baling