Cutting height is the cheapest change you can make to a hay field. It costs nothing, takes about an hour to set up, and it quietly decides how fast your hay regrows, how many years the stand lasts, how quickly the windrow dries, and how much dirt ends up in the bale. Yet most of us set the cutterbar once when the mower is new and never touch it again.
The trouble is that the "right" hay cutting height isn't one number. It changes with the species you're cutting, the cutting you're on, how hot and dry it is, and whether the crop is standing up or laid flat. Get it wrong in one direction and you thin the stand out; get it wrong in the other and you leave real tonnage in the field. This guide covers the numbers that extension agronomists publish, what experienced growers actually run, and the honest trade-offs on both sides.
Quick answer: Cool-season grasses — orchardgrass, timothy, tall fescue, bromegrass — should not be cut below about 3–4", and most experienced hay growers run 4–5". Pure alfalfa tolerates a much shorter cut, roughly 2–3", because it stores its energy reserves in the crown and taproot below ground rather than in the stem base. In a mixed alfalfa–grass stand, set the height for the grass, not the alfalfa. Raise the cut in heat and drought, on new seedings, and on first cutting; drop it only when you have a specific reason.
Why grass and alfalfa need completely different cutting heights
Almost every argument about stubble height dissolves once you understand where the plant keeps its groceries. A forage plant that has just been mowed has no leaf area left to photosynthesize with, so it has to fund the first days of regrowth entirely out of stored carbohydrates. Where those carbohydrates sit determines how much you can cut off without hurting the plant.
Alfalfa stores its reserves in the crown and taproot — below the soil surface, safely out of reach of any cutterbar. That's why alfalfa can be mowed close to the ground and still bounce back. Cool-season grasses store theirs in the base of the stem and in the tiller bases, which sit in the bottom few inches of the plant, right in the path of the knives. Cut a grass stand short and you are literally hauling the regrowth fuel off the field in the bale.
A grower on HayTalk put it more memorably than any textbook:
"Grasses store their sugars for regrowth in that white part of the stem--just above the ground. Cutting too short makes for a sweeter, tastier hay----once! Alfalfa stores its sugars in the crown, just under the ground. So it can be mowed almost at ground level."
— rjmoses · HayTalk thread 22997
The same grower offers the single most useful field rule we've come across for setting the machine, and it works on any species without a tape measure: look at the base of the plant and find the point where the stem changes colour from whitish to green, and set your cutting height there. That colour break is roughly where the storage tissue ends.
There is a second, less-discussed reason grasses need height. Cool-season grasses regrow from tillers and from growing points at or near the stem base. Scalp them and you don't just remove fuel, you remove the buds that were going to produce the next cutting. Alfalfa regrows from crown buds and from axillary buds on the remaining stubble, which is why a very close alfalfa cut is survivable and a very close orchardgrass cut is not.
Cutting height by species: the working numbers
Published extension guidance and real-world practice differ in an interesting way. Extension figures are usually stated as minimums — the floor below which you start damaging the stand. Experienced growers tend to run comfortably above that floor because they're optimizing for drying and stand life, not just survival.
| Crop | Published minimum | What growers commonly run | Why |
|---|---|---|---|
| Pure alfalfa | 2–3" | 3–3.5" | Reserves are below ground in the crown and taproot. |
| Orchardgrass | 3–4" | 4–5.5" | Least tolerant of close cutting; thins out fast if scalped. |
| Timothy | 3–4" | 4–5" | Corms at the stem base carry the regrowth reserve. |
| Tall fescue | 3–4" | 4–4.5" | More forgiving than orchardgrass but same principle. |
| Alfalfa–grass mix | Follow the grass | 3.5–4" | Set for the more sensitive species in the stand. |
| New seeding (year one) | 4" | 4" | Light header float matters as much as height. |
| Heat or drought stress | Raise above normal | +1" or more | Shades the crown and conserves soil moisture. |
Penn State Extension, Rutgers Cooperative Extension and University of Wisconsin forage specialists all land in the same territory: alfalfa can be cut in the 2–3" range without penalty, while cool-season grass hay should not go below 3–4", with 4" recommended in the establishment year. Rutgers is blunt enough to title its guidance around not cutting grass hay too low at all.
The forum consensus tracks that closely. As one long-time member summarized a discussion that ran for pages:
"4" or higher on grass hay is the general consensus. On straight alfalfa 2" is more the norm."
— Vol · HayTalk thread 87362
Why the mixed stand follows the grass
In an alfalfa–grass mix you have two species with opposite tolerances sharing one cutterbar setting. Set it for the alfalfa at 2" and you steadily weaken the grass component until it thins out and the field becomes a weedier, patchier version of itself. Set it for the grass and the alfalfa gives up a little yield but keeps going. The general rule is to protect the more sensitive species.
There's a nuance worth knowing, though: some growers deliberately use the alfalfa-friendly setting as a management tool. Running the lowest setting on a mixed stand takes just enough out of the orchardgrass to slow it from crowding the alfalfa out. That is a legitimate tactic if alfalfa is the component you're trying to keep — just understand you're trading grass persistence for it, on purpose.
What you actually gain by cutting higher
1. Faster regrowth and more total tonnage across the season
This is the counter-intuitive one. Leaving 2" more stubble looks like giving up yield, and on that individual cutting it is. Across a season, taller stubble often puts more hay in the barn because the crop comes back faster and you get more of it. One HayTalk member ran the comparison on his own ground after converting to a 3.5–4" stubble and reported going from 82 bales to 205 bales off the same 5–5.5 acres.
That's an unusually dramatic result and it clearly involved a stand that had been getting scalped. But the direction of the effect is consistent, and it's the single most common report from growers who switch:
"It is always worth cutting higher… Higher stubble will have 2 effects. Faster regrowth and more efficient drying."
— IH 1586 · HayTalk thread 102826
2. Longer stand life
Stand persistence is where the money really is, because reseeding is expensive and a year of establishment is a year of lost production. Growers running 4–5" regularly report getting a decade or more out of a grass stand with proper fertility, where the same field cut short goes thin and weedy in a few years. If you're constantly fighting to thicken a thin hay field, cutting height is one of the first things worth checking.
3. Faster drying — the reason a lot of people convert
This surprises people, but it's the benefit growers mention most after they raise the cut. A tall stubble acts like a mattress: it holds the windrow up off wet soil, lets air move underneath, and keeps the bottom of the swath from sitting in the dew and mud. One member who runs 4.5–5" described the effect on the whole hay chain:
"I added high skids years ago… really impressed with the gradual improvement in stand health. Definitely better drying… I shoot for 4.5-5 in stubble height."
— Hayman1 · HayTalk thread 102826
Another described cutting alfalfa around 4" specifically "so as to have a good circulation of air underneath for drying." If drydown is your bottleneck, this is worth as much as a tedder pass. See our guide on how to make dry hay faster for the rest of the levers.
4. Cleaner hay, fewer rocks, less knife damage
Cutting close drags the cutterbar through soil, gopher mounds, and rock. That means more ash in the bale, more chipped knives and guards, and more time in the shop. It also means dust in the hay, which buyers notice. One grower listed the whole set of reasons he stays at 4"+ on grass — quicker regrowth, better drying off wet ground, less weed pressure, less knife damage on rocks — and finished with the line that sums it up: "My buyers want hay not stems."
Lower ash content is not a small thing. Soil picked up at mowing follows the crop all the way through tedding and raking and ends up in the bale, where it dilutes energy and can contribute to dusty hay.
The honest downsides of high stubble
Almost every article on this subject stops at the benefits. The growers who actually run high stubble are more balanced about it, and the trade-offs are real. As one member put it plainly: stubble height is a compromise, and too much or too little can both cause problems.
You give up tonnage now — and how much depends on the cutting
This is the most under-appreciated point in the whole debate. The same 2" of stubble costs a very different fraction of the crop depending on how tall the crop is. One member did the arithmetic:
"On an average first cut of Timothy that is say 30" tall, 2" is about a maybe 7% difference in yield. That 2" on 10" tall 2nd cut makes about a 20% difference."
— slowzuki · HayTalk thread 76186
That is the practical case for being generous on first cutting and more thoughtful on short later cuttings. A grower on hilly ground in the same thread was candid that setting his 13-foot discbine to 5" would make the later cuttings barely worth taking — which is a completely legitimate position on a short crop.
Hay falls down into the stubble and stays there
A tall stubble is a mattress in a good way for drying and in a bad way for recovery. Cut hay settles down into it, and the rake and tedder can't always get it back out. One grower who otherwise runs high shoes named this directly as money left in the field, along with a related problem: tedder and rake tines tear green stubble off and mix it into the windrow, which slows drydown.
Rakes and tedders may need re-setting
You can't raise the cut and leave the rest of the chain alone. Growers who convert generally raise tine height on the tedder and rake to match. One noted a wheel rake will want to drag green stubble up into the windrow if it isn't adjusted. Budget an afternoon of fiddling with rake settings the first season.
And there are stands that just don't seem to mind
Good faith requires reporting the dissent. At least one member cuts timothy at 1.5–2" stubble and reports no thinning. Another — someone who otherwise advocates high stubble strongly — admitted he cut a timothy field as low as his discbine would go for 12 years and it still had 50–60% timothy at the end of it. Species, soil, fertility and rainfall all move this. The guidance below is a good default, not a law.
How to actually raise your cutting height
Most disc mower-conditioners can't reach 4–5" on their factory settings, which is why so many growers assume they're already cutting high when they aren't. Measure your stubble with a tape before you decide anything.
High-stubble skid shoe kits
This is the standard fix on a disc machine and it's a genuinely cheap upgrade. On one common New Holland discbine, the kit is eight bolt-on shoes — one under each turtle — that raise every position by about 2". Where the standard settings gave 1.5", 2.5" and 3.5", the kit turns them into 3.5", 4.5" and 5.5". The member who fitted his put the cost around $300 and the install at roughly an hour. His summary of the result was short: hay tedded better, dried better, raked better.
Check your own machine's part numbers — kits exist for most major disc mower-conditioner brands, and some Krone, Kuhn and John Deere machines offer factory high-cut shoes or extensions.
Cutterbar tilt
Tilting the cutterbar back raises the effective cut; tilting it forward lowers it and reaches further under the crop. This is your fast adjustment for changing conditions and it's what you'll reach for on a disc mower-conditioner when the crop is laid over. Many growers leave the head tilted back most of the season and only tilt forward when they need to get under something.
Sickle machines
On a haybine, cutting height is set by the skid shoes and by how the header floats. There are usually multiple shoe mounting holes; moving to a higher hole is the equivalent of a high-stubble kit. Sharp sections and good guards matter more here than on a disc machine.
New seedings: float pressure matters more than height
On a first-year stand the consensus is 4", but the more important adjustment is header float. Young alfalfa is not well anchored and a heavy header will pull plants out by the roots rather than cut them. Set your cutterbar float light on new seedings. Our guide to establishing an alfalfa stand covers the rest of that first year.
When to deviate from the standard height
- Heat and drought: raise the cut. A stressed stand has fewer reserves and taller stubble shades the crown and conserves soil moisture. This is also when a scalped stand is most likely to simply not come back.
- Lodged or flattened crop: the rules change entirely — you often have to tilt down and go lower just to get under the crop. That's a different job with different trade-offs; we cover it in cutting and baling lodged hay.
- Final cutting of the season: practice varies. Some growers cut the last one deeper to clean the field up, but pair that with enough regrowth time before a killing frost — commonly cited as five to six weeks. See should you take a last cutting.
- Second and third cuttings on short growth: where slowzuki's 20% figure bites. Many growers drop a setting on short later cuttings and accept the trade.
- Killing or rotating a stand: if the field is coming out anyway, cutting height stops mattering. Take everything.
- Rough or rocky ground: cut higher than you otherwise would. Smoothing the field is the long-term answer.
How cutting height shows up in the finished bale
Everything upstream of the baler lands in the bale, and cutting height touches two things we care about a great deal as a net-wrap manufacturer.
Moisture. Hay that dried on a stubble mattress instead of on wet soil comes in more evenly. Even drydown is what lets you bale inside the safe moisture band instead of gambling on a windrow that's bone dry on top and green underneath. Round bales going up in net want roughly 15–18% moisture, and uneven drying is a leading cause of the wet slugs that later drive bale heating. Our guide to baling moisture for net-wrapped bales has the working ranges, and a moisture tester is worth the money.
Soil and abrasion. Dirt scooped up by a scalping cutterbar rides through the whole system. In the bale it shows up as ash and dust; on the outside of the bale it is an abrasive that works against the wrap and against clean unrolling at feed-out. A cleaner crop makes for a cleaner, better-shedding bale — and for hay that doesn't cost you leaf that the buyer was paying for.
A five-minute cutting-height check
- Walk into a field you've already cut and measure the actual stubble with a tape in three spots. Most people are cutting shorter than they think.
- Identify the dominant species. If there's any meaningful grass in the stand, set for the grass.
- Find the colour break at the base of a plant — where whitish stem turns green. That's your floor.
- Check whether your machine can physically reach that height on its current settings. If not, price a high-stubble shoe kit.
- Raise tedder and rake tines to match before the next cutting.
Frequently asked questions
How short can you cut hay?
Pure alfalfa can be cut as low as 2–3" without harming the stand, because its energy reserves sit in the crown and taproot below ground. Cool-season grasses such as orchardgrass, timothy and tall fescue should not go below 3–4", since they store reserves in the stem base that the cutterbar removes.
What is the best cutting height for orchardgrass?
Extension guidance puts the minimum at 3–4", and most experienced growers run 4–5". Orchardgrass is one of the least tolerant cool-season grasses of close cutting, and repeated scalping is a common reason orchardgrass stands thin out and give way to weeds within a few years.
Does cutting hay higher reduce yield?
On that individual cutting, yes. How much depends on crop height: 2" of stubble is roughly 7% of a 30" first cutting but about 20% of a 10" second cutting. Across a full season, faster regrowth and better stand persistence often offset or exceed that loss on grass stands.
Does higher stubble really help hay dry faster?
Yes, and it's the benefit growers report most often after converting. Taller stubble holds the windrow up off wet soil and lets air circulate underneath, so the bottom of the swath dries closer to the same rate as the top. That evenness matters as much as raw speed when you're deciding whether to bale.
What cutting height should I use on a new seeding?
About 4" in the establishment year, for both grass and alfalfa. Just as important, set your header float light: first-year alfalfa is poorly anchored and a heavy floating cutterbar will pull young plants out by the roots instead of cutting them cleanly.
How do I raise the cutting height on a disc mower-conditioner?
Two ways. Tilt the cutterbar back for a quick change, or fit a high-stubble skid shoe kit for a permanent one. A typical kit bolts eight shoes under the cutterbar turtles and raises every setting by about 2" — for example turning 1.5", 2.5" and 3.5" into 3.5", 4.5" and 5.5".
Related guides
Featured photo: John Deere 1207 mower-conditioner, cut grass by liz west, licensed under CC BY 2.0, via Wikimedia Commons.
