Many gardening writers say never to use hay as mulch. The stated reasons are that it contains seeds, and the stems of the plants are hollow so it doesn’t break down quickly. Also, Hay has historically been more expensive than straw, since hay is a food and straw is a waste product. I think all of this is basically misguided and no longer reflecting the reality of contemporary farming patterns.
- If you are making good hay, there should be few if any seeds, because you are cutting before it forms seeds. Straw is a different story, since it almost always will have some weed seeds since the crop went a whole season before being cut.
- The fact that hay breaks down more slowly, I think, is a good thing. I also don’t really see much of a difference anyway. I mulch to provide fertility, retain moisture in the soil (so it isn’t bare), and prevent weed growth (through shading effects). So, slow breakdown is good. Also, Red clover hay is dark colored and absorbs sunlight heat well and keeps the soil warm.
- Straw is the byproduct of small grain production. Small grain production is only practical on a large scale with the use of modern harvesters. It is a waste of time for the small grower. Therefore, straw is going to be something bought by the small farmer. Hay is easily made on even the tiniest of scales (like a backyard), and so is basically free. Also, straw prices have been higher than hay for several years now, supposedly because highway departments have learned that seeding down grass with a straw mulch works better than shredded newspaper or nothing besides seeds. Also, high-yielding semi-dwarf wheat, which is mostly what is grown today, doesn’t make half as much straw as old fashioned tall wheat per acre. Modern hayseeds make more hay than ever per acre.
So, what does this look like? Hay mulching seems best on cucurbits. Here is some around various squashes. I think it works nearly as well as black plastic mulch, and unlike black plastic mulch, you just put it down and don’t have to pick it up at the end of the season.
Also, growing hay for mulching works well in a garden rotation. If you grow Red Clover, or Red Clover + some Sweetclover (don’t use as feed), in the sections of your garden that are “resting” between rotations of garden plants, you will have a ready and nearby source of mulch. Also, legumes will fix their own nitrogen and add some back to the soil, increasing the fertility WHILE they are producing mulch. And of course, if you have animals, Red Clover hay is excellent feed (though it is so rich, I think it should be cut with grass of some sort).
I’ve worked this system out for three years now. It works pretty well I think, though I keep finding improvements. It seems optimal when the garden is 1/2 and 1/4th the size of the “hayfield” used to produce mulch. This may seem wasteful in the sense that you are only producing vegetables on a fraction of the available space, but the trade off would be having to purchase in straw or some other inorganic fertilizer.
And you can directly compost hay (not something you can do with plastic mulch). Just throw it in the pile with whatever and let it rot. What I do is use SPOILED hay, unfit for animal consumption because either it was rained on or rotted in storage, and compost it along with the straw-manure deep bedding I use in the barn to keep animals over the winter. I’ve found this mixture works well and is fairly flexible, and the time of year when you are making hay is the same as when you should be cleaning out the barn and building compost piles.
Straw does make a superior bedding to hay. And I think it is worth purchasing and generously applying for that purpose. Also, since many animals benefit form moderate grain supplementation, I think using the straw for bedding makes sense, since it balances out nicely.