Please: no comments yet from the soil, mulch and compost posters. Nor the organic gardening posters. Let’s first see what the others have to say.

Break them up and mix it in. The manure should help heat it up and kill most weed seeds and the mold is not an issue.

tj

Aaarrrgggh.

I was hoping to read about the dangers of permitting dissimiliar components

of compost (to be) from mixing with each other, particularly when

one constituent was already being acted upon by one or more of a

taxonomically diverse number of fungal species.

Not an issue. There is always a myriad of different bacteria and fungi at work depending what is available and their growing conditions.

tj

I would use it in my compost or as mulch---probably as mulch. A moldy bale of hay is a wonderful thing.

And btw there is no need to add any soil. As for mixing dissimilar components that’s a very good thing, not a negative.

Everything depends on what these bales are made of. My Uncle one time brought old moldy hay to his garden. After that all his vegetables had got sick, no crop. He stopped having veggies on that plot. Still trying to clean soil by sederates, several years passed already.

I would let those bales stay in the field, where they are belong.

I’m not sure about a bale of hay, moldy or not. Straw - yes, hay - no.

Will a hot compost pile destroy all weed and grass seeds in the hay?

I don't have to worry about the seeds in hay, because I mulch, but If you don't mulch, it could be an issue.

tsugajunkie pointed out the big risk with hay, straw, and manure. The aminopyralid class of herbicides persists through composting and through animals' digestion and damages all broadleafed plants, and allows only the grass family to grow well. So it is used on grasses such as hay and grains (from which we get straw). The problem described by avgusta_gw was probably caused by this, not by the mold on the hay, which is great for composting.

There are simple tests you can do to make sure the hay is not contaminated with aminopyralid-type herbicides. Just try germinating a few beans in pots indoors in potting soil with and without the suspect hay. If the beans quickly get deformed, you know the hay is not safe for the garden. If they come up in good shape then it's fine.

Moldy hay is a great addition to compost, or as a mulch on its own. It may have a lot of weed seeds, but deep mulching will prevent most of them from getting sun and growing, and the few that do come through will be shallow-rooted and easy to pull. Or hot composting should kill most of the seeds.

I would be happy to get a load of moldy hay, because it's difficult to get any kind of waste biomass where I live.