Quick answer: Finished bales burst for a short list of repeatable reasons — a bale filled unevenly across its width with too much chamber pressure, too few wraps for a springy crop like rotor straw or cornstalks, dry material that swells after it takes on moisture, net gone brittle from a season or two of UV, and rough or repeated handling of a loose roll. Quality net helps, but most "bursting" is a fill, density, wrap-count, or storage problem you can fix. Aim for a uniform bale, use at least 2.5–3 wraps (4 on springy straw or stalks), and keep bales up off wet ground and out of full sun.
There are two very different "net wrap breaking" problems, and mixing them up sends you chasing the wrong fix. One is net tearing at the baler while you wrap and eject — that is a machine-settings issue we cover in net wrap tearing when baling. This guide is about the other one: finished bales that pop open, split down the middle, or shed their net days or months later in the field, the stack, or during handling. Hay-forum threads on bursting bales come back to the same handful of causes, so let's walk them in the order farmers actually find them.
Cause 1: an uneven, over-dense bale
The number-one way to make a bale burst has nothing to do with the net itself — it is a bale packed harder in the middle than at the edges. A long-time round baler laid it out plainly:
"The best way to make net burst on a bale is to make a bale that is not uniformly filled across its width, with too much chamber pressure, and put too little net on for the circumstances. Do that in cornstalks and you can make nearly every bale burst."
— Gearclash · HayTalk thread 93856
The tell is where the bale fails. When bales burst, they usually bulge and split in the middle, not at the ends — a sign the chamber was overfilled in the center where the net has the least help holding it:
"all of these bursting bales expanded at middle, not the both ends."
— haoyou110 · HayTalk thread 93856
Weave the windrow across the full width of the pickup so the chamber fills edge to edge, and back the density off if the center is packing hard. A uniform bale spreads the load across the whole width of net instead of concentrating it on one bulging band. If your bales will not hold their shape at all, start with round bales not holding shape.
Cause 2: too few wraps for the crop
Springy, coarse crops store energy like a compressed spring and need more net to contain it. Rotor-cut wheat straw is the classic offender — dry, stiff, and cranked tight:
"the bales will expand and cause issues... it can be problem in rotor wheat straw esp with NH baler cranked tight and under 3 wraps, we recommend 4 in that situation."
— swmnhay · HayTalk thread 93856
"+1 on the rotor straw, seems almost like a over compressed spring, something has to give if not enough wraps. They are something to see after the explosion too, wouldn't think it would be that big of a pile."
— r82230 · HayTalk thread 93856
Two and a half to three wraps is the everyday minimum for grass and alfalfa; move to four on rotor straw, cornstalks, and anything you bale dry and tight. If you are not sure what your baler is actually laying on, see how many wraps per bale and, for stalks specifically, net wrap for cornstalk bales.
Cause 3: dry bales that swell after they take on moisture
Here is the one that surprises people: a bale can sit fine for weeks, then burst after a wet spell — because the dry material inside rehydrates and expands against net that was already near its limit:
"There is one odd situation I have seen, very dry tight cornstalk bales bursting the net somewhat after a prolonged period of wet weather. My assumption is that the material in the bale expanded when it took on moisture."
— Gearclash · HayTalk thread 93856
The fix is storage, not the baler: keep bales up off wet ground, leave a gap for air between rows, and shed rain off the top where you can. A bale baled bone-dry and tight has the least room to swell, so it feels the moisture-expansion pressure the most — one more reason to give springy, dry crops an extra wrap. For the full storage picture see net-wrapped bale storage outside and does net wrap go bad in storage.
Cause 4: UV and net quality over the long haul
Net is a plastic, and sunlight slowly makes plastic brittle. Good UV-stabilized net shrugs off years outdoors; thin or poorly stabilized net can crumble in a single season. A north-Texas producer who bales in punishing sun has seen both ends of that range:
"Some of my bales have been stored outside in the N Texas sun for over 2 yrs. I've seen some solid white net that didn't last the 1st year without some deterioration."
— Tx Jim · HayTalk thread 93856
Manufacturing consistency matters too — the thinner a net is stretched, the harder it is to keep every strand uniform:
"The thinner the net wrap, the harder it is to keep consistent during manufacturing. If net is breaking after it is on the roll then it may need more wraps."
— Tim/South · HayTalk thread 93856
If bales you plan to store a year or more are failing, look at the net grade and where it sits. Buy UV-stabilized net, and store long-term bales under cover or at least out of all-day sun. More on that in UV protection and bale net wrap.
Cause 5: handling stress (and the occasional deer)
Every time a bale is speared, stacked, hauled, and re-handled, the net takes a shock load. A loose bale takes those shocks worse than a tight one:
"How many times a roll is handled can also be a factor... A loose, floppy roll will come apart quicker than a nice tight well formed roll. If you spear the roll and it sags then it is time to gear down and move slow."
— Tim/South · HayTalk thread 93856
And once in a while the cause is genuinely not your fault:
"one other bizarre thing I have seen in my life that led to damaged net / exploded bales. Deer... net damage to a bale that had to have come from a buck that took out his hormone driven irritation on a random bale in the back of a field."
— Gearclash · HayTalk thread 93856
The takeaway: make a tight, well-formed bale, and if you are moving them a lot, slow down and handle them gently.
Causes and fixes at a glance
| Symptom | Likely cause | Fix farmers use |
|---|---|---|
| Bale bulges and splits in the middle | Uneven fill, over-dense center | Fill the chamber edge to edge; back off density |
| Straw or cornstalk bales burst | Too few wraps for a springy crop | Go to 4 wraps on rotor straw and stalks |
| Dry bales burst after a wet spell | Material rehydrated and expanded | Store off wet ground and under cover; add a wrap |
| Net brittle or crumbling after a season+ | UV degradation; thin or low-grade net | Use UV-stabilized net; keep long-term bales out of sun |
| Bales let go during handling | Loose, floppy bale; too much handling | Bale tight and uniform; slow down, minimize moves |
Where XES fits
When the fill, density, and wrap count are right, the net should not be the weak link. Our wrap is DLG-tested (Report #7439) for consistent strength across the full width of the roll, and it is UV-stabilized to hold that strength through seasons of outdoor storage — so a uniform, properly-wrapped bale stays a bale. It cannot rescue an uneven, overpacked, under-wrapped roll, but it removes "bad net" from the list of suspects. Compare widths and lengths on the net wrap product page, and match your wrap count to the crop with how many wraps per bale.
The bottom line
Bursting is almost always a bale-making and storage story, not a mystery. Fill the chamber evenly so no band carries the whole load, keep density sensible, and put enough net on for the crop — 2.5 to 3 wraps for hay, 4 for springy straw and stalks. Store bales up off wet ground and out of full sun so they neither swell with rain nor go brittle in UV, and handle tight bales gently. Do that and "the net keeps breaking" quietly turns into bales that stay shut until you feed them.
Frequently asked questions
Why do my bales burst open in the middle?
A bale that splits in the middle was almost always filled harder in the center than at the edges. The net has the least support across that central bulge, so when chamber pressure is high there, that is where it lets go. Weave the windrow across the full pickup width so the bale fills evenly, and back the density off if the center packs hard.
How many wraps of net stop a bale from bursting?
Two and a half to three wraps is the everyday minimum for grass and alfalfa. Springy, dry crops like rotor-cut wheat straw and cornstalks store more energy and commonly need four wraps — producers baling those tight specifically recommend stepping up from three to four. More handling and longer storage also argue for an extra wrap.
Can dry bales really burst after rain?
Yes. Very dry, tightly packed material swells as it takes on moisture, and that expansion pushes outward on net that was already near its limit. Bales can sit fine for weeks and then let go after a prolonged wet spell. Storing bales up off the ground and shedding rain off the top reduces how much moisture they pick up.
Does UV break net wrap?
Over time, yes. Sunlight gradually embrittles the plastic. Quality UV-stabilized net holds up for multiple seasons of outdoor storage, while thin or poorly stabilized net — some solid-white product, for example — can deteriorate within the first year. For long-term outdoor bales, use UV-stabilized net and keep them out of all-day sun.
Is bursting the net's fault or mine?
Usually it traces to bale making or storage: uneven fill, too much density, too few wraps for the crop, moisture swelling, or UV on cheap net. Good net removes one variable, but it cannot hold an overpacked, under-wrapped, unevenly filled bale together. Fix the bale and the storage first, then make sure you are running quality, UV-stabilized wrap.
This guide is maintained by the XES Netting team — a bale net-wrap manufacturer. Every farmer quote in this post is verbatim with a thread link, so you can go read the originals. Always follow your baler's operator manual and lock out the machine before adjusting the net system or reaching into the chamber.
Featured photo: Bale - Voglje, Šenčur by Mihael Grmek, licensed under CC BY-SA 3.0, via Wikimedia Commons.
