Last Monday, after two days of dry weather I took down some of the hay racks that we built at the end of July. It was the first chance to compare how the racks with and without canvas “hats” have fared.
The racks have had 133.5mm of rain on them over the four weeks that they have been standing. This included one soaking of 40mm in 24 hours, the kind of rainfall that we have found the racks to be the least resistant to.
The first one I took down had no hat. I removed the layer of hay from the top of the rack and was disappointed to find a patch of mouldy hay just underneath. This was on the south west face, and appeared to be where moisture managed to penetrate the top “thatch” enough to soak the hay, perhaps pushed in by the prevailing winds. The rack top had settled to a less then ideal profile with a dip in the middle, as can be seen in the photo below, probably because insufficient hay had been put on top. It was also made from the hay that had the least amount of drying time on the field, which may have been a contributing factor.
Lower layers of the rack were fine, although not of the highest quality, and were taken to the barn. The mouldy hay was not wasted, but was used as mulch in areas where we are establishing new forest garden areas and edible hedges.
The next rack had a hat, and was much more satisfying. Even from the outside, the sheltering effect of the “hat” could be seen. Exposed hay on the outside was weathered to a pale gray, but on the ends and under the hat it was still a golden green. The quality was much better as well, and I did not reject any of the hay. Again, the quality improved as I moved down the layers, moving from adequate hay at the top to reasonably sweet smelling near the bottom. There was a slight drop in quality at the very bottom, possibly due to ground moisture and splash where the hay hung very close to the ground.
The next rack I took down was again hat-less, but much better then the first. I did put the very top covering layer aside for mulching, but below that the hay was fine and on the lower layers, as good as the hay on the “hatted” rack. This rack had had a much thicker layer put on top, and maintained a much better profile as it settled then the first rack.
I took down several more racks, both with hats and without. My observation so far is that the canvas hats are valuable in helping to cure the hay well on racks, with much less if any damage to the hay from persistent damp. Racks with well built tops also performed well, although I generally still put the very top most layer aside for mulch and the top layers of hay were of slightly lesser quality then that on the hatted racks. Racks with poorly built tops (there were two) showed signs of damage from persistent damp in the hay on the exposed side, a larger proportion of the hay was fit only for use as mulch and the rest was of generally lower quality.
Therefore, it would appear that canvas hats are a useful addition to the style of racks we use. The major disadvantage is having to acquire suitable material to make them. We used old cotton yurt canvas, which will shed the worst of the rain but still allow the hay to breathe. It would be interesting to see how plastic woven canvas or tarps would perform. These are perhaps more readily available but there may be problems if the hay on the rack is not able to dissipate it’s internal moisture through a covering that is too water impervious.
Racks without hats can perform almost as well, perhaps maybe as well, but a well built top is critical. We are improving with practice over the years! The major reason we have experienced for the failure of the top of a rack is putting insufficient hay on the top, such that as it settles it does not form a thick enough cover, a mistake many beginners make. Shape is also important, and we try to aim for a rounded top, sloping in all directions to shed rain.
The other reasons we have encountered for failure of racks in the past is packing the hay too tightly onto the rack and filling them with hay that is too green.