Every day a cutting lies in the field is another roll of the dice with the weather. So the producers who consistently dodge rain have learned to make dry hay fast — sometimes baling barely a day after they cut. It isn't luck or a magic machine; it's a handful of principles about how a plant gives up water, used in the right order. One Michigan hay maker documented his "30-hour hay" in enough detail to learn from, and the agronomy behind it (pan evaporation, leaf stomata, wide swaths) is what lets you compress a four-day job into one or two.
Quick answer: Hay dries fastest when you spread it to nearly 100% of the cut width immediately, so the leaf pores (stomata) keep breathing out moisture in daylight. The two strongest drying agents are low humidity and a light breeze; pan-evaporation (PE) numbers tell you whether a day will actually dry hay. Condition the stems, ted right after cutting, and rake into a fluffy windrow only once most of the drying is done. In good conditions producers bale dry hay about 30 hours after cutting. Narrow windrows, thick mats over ¾", and high humidity are what keep hay wet for days.
The whole game: keep the leaf pores open in daylight
A cut plant doesn't know it's dead. Its leaf pores — stomata — keep transpiring water as long as they see daylight and the plant is above roughly 47–48% moisture. Once it drops below that, they close for good and the rest of the water has to leave the slow way, through the stem. So the fastest drying happens early, and only if the leaves are exposed. The Michigan hay maker's summary of what matters:
"Some key things - Pan evaporation (PE) numbers are important. Spreading hay to 100% ASAP. The stoma openings and how soon the permanently close. Rotary rakes, make a fluffy windrow."
— r82230, Thumb of Michigan · AgTalk thread 1116180
The practical consequence is the most important sentence in this whole article: spread the hay wide the moment you cut it. A thick, narrow mat shades its own leaves, the stomata can't see daylight, and the bottom of the clump stays as wet as the minute it was cut — for days.
The 30-hour timeline, step by step
Here's the documented run that produced lab-tested 10.8% hay off an alfalfa/grass mix, cut to baled in about 30 hours:
"I starting cutting at 10 am day 1. I'm cutting with a NH discbine, with roll conditioning. I ted the hay right after I finish cutting... I start raking hay at noon as dew burns off, day 2... Start baling at 4pm day 2... So, I'm starting to bale 30 hours after I started cutting, hence the calling it 30-hour hay."
— r82230, Thumb of Michigan · AgTalk thread 1116180
| When | Operation | Why |
|---|---|---|
| Day 1, ~10 AM | Cut with conditioner, spread wide | Crack stems; expose leaves to daylight |
| Day 1, right after cutting | Ted | Spread to ~100% so stomata keep breathing |
| Day 2, ~noon | Rake into a fluffy windrow as dew burns off | Most drying already done; rake fluffs for airflow |
| Day 2, ~4 PM | Bale | ~30 hours from cut; lab-tested dry |
Note the order: ted early to dry fast, rake late to finish — not the reverse.
Read the day before you cut: humidity, breeze, and PE
Two weather factors do most of the drying, and they're not the ones people expect — it's not really about heat:
"I had light breeze and low humidity which are the two strongest drying agents for dry hay making. I had 6-7MPH winds, humidity of as low as 27%, even with a partly cloudy day 2."
— r82230, Thumb of Michigan · AgTalk thread 1116180
A partly cloudy day still made fast hay because the leaves only need daylight, not direct sun, to keep transpiring. The number that ties it together is pan evaporation (PE) — a published measure of how much water the air will pull out on a given day. A high-PE day with low humidity and a breeze dries hay even if it's not blazing hot; a humid, dead-calm day won't dry hay no matter how warm. Checking PE turns "I think it'll dry" into a decision you can defend.
Why a thick mat won't dry — and how you cut matters
The single biggest mistake is leaving hay in a narrow rope or thick clump. Below about ¾" of mat thickness the leaves get daylight and keep working; thicker than that and the bottom stays fresh-cut wet. That's the agronomic reason "spread to 100%" beats every other trick. The cutting setup that supports it:
"I cut at around 3" height, discbine rollers are set to they are not quite touching, I leave hay spread just about wide enough not to drive on."
— r82230, Thumb of Michigan · AgTalk thread 1116180
Conditioning rollers crack the stem so the slow-drying stems lose water faster once the stomata close, and a 3" stubble keeps the windrow up off the ground in airflow. Rake choice matters at the finish, too — a rotary rake fluffs a windrow that air moves through, where a tight rope traps moisture. See our rake selection guide for the trade-offs.
Regional reality check
Thirty-hour hay is a function of conditions, not a promise. In low-humidity, high-PE country, hay cut in the morning can bale before dark; in humid regions you may never get below 16–18% no matter what you do, because the air itself holds too much water. The principles still apply everywhere — spread wide, ted early, rake late, read the humidity — they just compress more or less time depending on where you farm. Use them to take days off your normal window, even if "30 hours" isn't on your menu.
Where XES fits
Getting hay dry fast is half the battle; keeping it that way is the other half. The drier and faster you bale, the better the bale stores — but it still has to hold its shape and shed weather through the season. Once you've made good dry hay, protect it: bale at the right density, put enough wraps on for your storage time (see how many net wraps per bale), and keep it off wet ground. XES Extreme net wrap is DLG-tested (Report #7439) and UV-rated 12 months (tested to ISO 4892-2), so the dry hay you worked to make stays tight and protected. Compare sizes on the net wrap product page.
The bottom line
Fast hay isn't about horsepower — it's about physics. Spread the crop wide the second you cut so the leaf pores keep venting moisture in daylight, condition the stems, ted early, and rake into a fluffy windrow only at the finish. Read humidity and pan evaporation instead of guessing, and in good conditions you'll bale dry hay in about 30 hours. Even where the air won't let you hit that, the same moves take real days off your window — and every day out of the field is a day the weather can't ruin your cutting.
Frequently asked questions
How fast can you make dry hay?
In low-humidity, breezy conditions producers bale dry hay about 30 hours after cutting — cut mid-morning day one, ted immediately, rake the next midday, and bale that afternoon. In humid regions it takes longer because the air holds more water, but spreading wide, tedding early, and raking late still removes days from a normal drying window.
What makes hay dry faster?
Spreading it to nearly the full cut width immediately, so the leaf pores keep transpiring in daylight, plus low humidity and a light breeze — the two strongest drying agents. Conditioning the stems and keeping the mat under about three-quarters of an inch thick also speed drying. Heat matters less than humidity and airflow.
Should I ted or rake first?
Ted first, right after cutting, to spread the hay wide for fast early drying. Rake last, once most of the moisture is gone, into a fluffy windrow that air can move through. Raking too early ropes the hay into a thick mat that traps moisture and slows everything down.
What is pan evaporation and why does it matter for hay?
Pan evaporation is a published measure of how much water the air will pull out of an open pan on a given day. A high pan-evaporation day with low humidity and a breeze dries hay fast even when it is not especially hot, while a humid, calm day will not dry hay no matter how warm. Checking it helps you decide when to cut.
Why won't my hay dry in the windrow?
Usually because it is in a windrow too soon and too thick. A mat over about three-quarters of an inch shades its own leaves, the pores cannot see daylight, and the bottom stays as wet as freshly cut for days. High humidity compounds it. Spread the hay wide right after cutting and only rake it up near the end.
This guide is maintained by the XES Netting team — a bale net-wrap manufacturer. The 30-hour example is one producer's documented method, shared verbatim with a thread link. Drying speed depends heavily on your climate, crop, and equipment — these are producer-reported practices and general agronomy, not guarantees.
Related guides
Featured photo: A Claas rotary tedder by Alan Hughes, licensed under CC BY-SA 2.0, via Wikimedia Commons.
