{"id":1217,"date":"2026-07-29T03:54:12","date_gmt":"2026-07-29T03:54:12","guid":{"rendered":"https:\/\/foragebaler.com\/?p=1217"},"modified":"2026-07-29T03:54:12","modified_gmt":"2026-07-29T03:54:12","slug":"baling-hay-in-high-humidity","status":"publish","type":"post","link":"https:\/\/foragebaler.com\/id\/baling-hay-in-high-humidity\/","title":{"rendered":"Membalut Jerami dalam Kelembapan Tinggi"},"content":{"rendered":"
Humidity Management Guide \u00b7 Southeast Strategies \u00b7 Hay Preservatives<\/p>\n
High humidity during hay baling is not simply inconvenient \u2014 it directly affects the moisture content of bales, the quality that reaches the buyer and the safety of stored hay in the barn. Understanding exactly what humidity does to a windrow and how to manage the risk separates operations that consistently produce premium hay from those that struggle with heating and rejection.<\/p>\n
Covers: how humidity re-wets hay \u00b7 RH vs dew point \u00b7 safe thresholds \u00b7 bale heating risk \u00b7 Southeast strategies \u00b7 hay preservatives \u00b7 machine adjustments<\/p>\n
A windrow that reached 15% moisture at 14:00 on Day 3 of curing can register 20\u201322% moisture core readings the following morning without any rain. This is not a measurement error \u2014 it is the result of moisture vapour from humid air being absorbed into the hay fibre when air temperature falls below the dew point temperature overnight.<\/p>\n
The re-wetting process works through the same mechanism as curing but in reverse: as air temperature falls after sunset, relative humidity rises toward 100% and eventually reaches the dew point temperature at which the air can no longer hold all its moisture vapour. Below the dew point, moisture condenses onto surfaces \u2014 including hay fibres in the windrow. The outer layers of the windrow absorb this condensate first. By dawn, the windrow surface may have absorbed 4\u20138 percentage points of additional moisture compared to its peak-dry late-afternoon reading.<\/p>\n
The critical insight: this re-wetted surface moisture is real moisture that enters the bale during compression. It is not simply cosmetic surface dampness. A probe moisture meter reading from the windrow core at 08:00 reflects both the residual core moisture from the previous day and the moisture that has migrated from the re-wetted surface inward overnight. Baling at this early morning reading produces bales that will heat.<\/p>\n
Relative humidity tells you what percentage of the maximum possible moisture the air currently holds at its current temperature. It does not tell you how much moisture that is in absolute terms. At 10\u00b0C, air at 80% RH holds approximately 7.0 g\/m\u00b3 of water vapour. At 30\u00b0C, air at 35% RH holds approximately 10.7 g\/m\u00b3. The warm afternoon air at 35% RH holds more moisture per cubic metre than the cool morning air at 80% RH \u2014 yet the morning reading sounds more alarming.<\/p>\n
Dew point temperature is stable through the day (assuming no weather fronts move through) and directly indicates at what temperature condensation will occur. A dew point of 15\u00b0C means that any surface cooler than 15\u00b0C will collect condensation from the air. If the nighttime temperature falls below 15\u00b0C \u2014 which it will in most regions except the Gulf Coast in peak summer \u2014 the windrow surface will be wetted. The lower the dew point relative to the predicted nighttime minimum temperature, the less overnight re-wetting will occur.<\/p>\n
Low overnight re-wetting. Morning baling may be feasible if previous afternoon core moisture was below 17%. Check with probe meter before starting.<\/p>\n<\/div>\n
Moderate overnight re-wetting. Standard afternoon baling window applies (13:00\u201318:00). Probe test windrow core before starting each session.<\/p>\n<\/div>\n
Significant overnight re-wetting common. Narrow afternoon window (14:00\u201317:00). Southeast and Gulf Coast summer conditions. Consider preservatives.<\/p>\n<\/div>\n
Heavy re-wetting and short window. Gulf Coast peak summer. Window may be only 2\u20133 hours. Preservatives likely required for any mid-season baling.<\/p>\n<\/div>\n<\/div>\n
All hay bales heat initially after baling \u2014 this is normal and expected. Fresh hay contains residual plant respiratory activity and microbial populations that produce heat as the bale stabilises. The question is how high the temperature rises and for how long. A correctly baled small square bale at 15\u201316% moisture will reach a maximum temperature of 40\u201348\u00b0C within 3\u20137 days of baling and then cool to ambient over the following week without significant damage.<\/p>\n
A bale made at 19% moisture reaches 55\u201365\u00b0C within 48\u201372 hours. At this temperature, Maillard reactions begin \u2014 the protein in the hay binds to fibre components in a form that ruminants cannot digest. This protein is still visible in a crude protein analysis but is nutritionally unavailable. A bale that heated to 60\u00b0C may analyse at 18% crude protein but have only 12\u201313% available protein \u2014 a significant quality reduction that buyers cannot detect without acid detergent insoluble nitrogen testing.<\/p>\n
Above 70\u00b0C, fire risk becomes real. Small square bale stacks in covered barns have caused significant barn fires from hay baled at excessive moisture. A bale stack that cannot be touched on the outer surface due to heat within 3 days of baling is at risk. Use a metal rod inserted deep into the stack as a temperature probe \u2014 if the rod is hot to the touch after 30 seconds inserted 60cm into the stack, the stack requires immediate spreading to dissipate heat.<\/p>\n