Hay is grass, alfalfa, timothy, clover, etc. that cows eat. Straw is the stem left over after oats, wheat, barley, etc are harvested.
Wheat stems are hollow and have good tensile strength. Hay has seeds in it (like weed seeds). Straw is just the chaff and very few seeds.
Most of the cob books and experts have said we should not use hay for building with cob, rather than straw, but I'm completely at a loss about WHY. I've received all kinds of different answers.... "It will sprout" (so what)... "It's not as strong" (huh??)
For instance, in the Becky Bee book she says "Do not use hay. It decomposes." Yet a few sentences later she states, "If you're an ambitious purist, you can gather your own grass stalks or experiment with other plant fibers." Well, HELLO, what do you think hay is? Grass stalks. Not to mention, as an avid composter, I can tell you that "straw" decomposes just the same as "hay"... and "hay" can mean anything from brittle stalks with seed heads to thick straps of wide grass to bales of weeds and wild rose stalks and willow branches..
Can anyone give me a reason that makes sense to me why we shouldn't just use my neighbor's weedy hay for building with cob?
I think that generally, straw refers to the cellulose stalks of a grain plant, whereas hay can mean the leaves, stalks and seed heads of a green manure crop such as alfalfa, clover, bromegrass and the like.
- No real food value
- Long, skinny fibers are convenient to work with
- Good tensile strength
- Lots of good eating there. As they say, hay is for horses.
- Prone to sprouting and rotting
- Probably a bit more difficult to work with, with all the plant parts present
- Possibly less tensile strength as it's not strictly stalks
When people say to avoid building with topsoil, I think it's a similar argument. Topsoil built up over eons is far too valuable to be used as a building material. Better to remove it for gardens and use the free-of-organic-matter subsoil for building.
Georgia Adobe wrote:Hello Mr. Rigg,
I would answer that Ms. McBride 's answer is more correct , as that Hay is for animal feed. Also, Hay can spontaneously combust , thus - I would NEVER BUILD - with hay bales – nor would I build with Straw bales except for emergency construction situations. I might would also say, don’t build with cob either , go ahead and build a proper wall by ramming the building soil in place . Rammed Earth ( a higher form of Cob ) makes for much safer and longer lasting walls!
Additionally, If your lucky enough to have a quality Hay Field, If your not feeding it to your live stock, you might should be selling it and buying Wheatstraw as that even just good quality Hay, brings a pretty penny .
Best Wishes & Happy Building !
Joe Woodall, Rogue Eco-Architect
Thus , as I said, I always choose 1st, All Masonry Homes - Built Mostly Of Properly Insulated & Moisture Proofed Rammed Earth + up to 80% recycled materials .
Nathan Rigg wrote:We just purchased 11 acres. It is an old pasture land that has been used as a hay field now. I've been reading books on cob and found that they recommend using straw instead of hay. The main thing i've saw is that they say hay decomposes...but so does straw. If I let the hay dry out before harvesting would it be fine to use? Maybe it is cheap enough it would be better to just buy it but I'd like to use everything I can from my property. Of course if we don't get out of this drought here in Texas I may not get much hay anyways.