“Straw” too green to be harvested?

Hey folks.  Love the depth and breadth of experience in this community.  

We’re getting close to buying bales for a small timber frame sb wrapped cottage.  I found a listing for rye straw that’s 15 minutes down the road.  My concern is, he’s just harvesting rye, grain head and all that was grown to sell as straw.  It’s still kinda green as it’s still May.  My own winter rye that we planted for erosion control still has soft grains if you squeeze them.

Does any one have experience with when cereal grains are dry enough for straw bale building sans moisture meter? Usually it would be cut after the grain is harvested and straws are quite golden of course, but this is a different situation.  Last thing I want is too much residual moisture trapped in there.  

I’ve got a more ‘reputable’ broker that’s further out for straw but the shipping would add 500 to cost.  That’ll be well worth it if it is harvested at a more appropriate time.

We’re in Tennessee river valley for reference.

Cheers,
Eric

Your caution is critical.
Straw must be dry.
Perhaps look at this also;
https://www.buildingwithawareness.com/the-pros-and-cons-of-straw-bale-wall-construction-in-green-building/
The $500 you speak of, is that $500 more than $1000 or $500 more than $100, it is relevant?
Good luck with the build, can you post details?
Will you capture rainfall for domestic use, my signature has some information.

Eric Weavet wrote:My concern is, he’s just harvesting rye, grain head and all that was grown to sell as straw.  It’s still kinda green as it’s still May.

If it were me, I'd be concerned that the presence of the grain would attract insects and mice. Straw that is almost only the "straw" part with no grain, is not particularly appetizing as it has virtually no nutritional value. Add even unripe grain to it - well, I know how interested my ducks are to the unripe grass seed heads in my field!

I agree with the other posters. In my opinion if the rye is harvested green then it is hay not straw, we've had previous discussions about the implications of using hay for building here for example. I think it's worth $500 for better straw. Pity you can't get any more locally - maybe later in the year?

Nancy beat me to it. I believe what he is selling is hay. I don't think the moisture content is all that's critical. I would worry about the sugar and nutritional content of the entire plant. In your area and humidity, I would go to every length possible to get the straw least likely to mold\rot\draw vermin, etc.

I agree with everyone on this--be cautious!  

Out here in the arid west farmers harvest the grain (cut the tops off the straw stems), then cut the straw near the ground after it has dried even further--usually down to around 12% - 15% MC.  Depending on the equipment they use and the qualities of the bale they want to end up with, it should have some dampness or else the stalks will shatter when being cut, bunched, and compressed into a bale. They usually bale suitably dried straw during the morning hours while there's still a little dew.  

The issue of grain present in the straw is also something of a concern if you're not going to plaster or otherwise seal the bale walls right away.  It is a food source for pests if they can get at it.  I always find some residual grain in the bales I work with, but very little, and it's not a problem so long as we do a good job sealing the walls so there's no access for critters.  

If you can get your hands on some bales and a moisture meter, find out what the moisture content is.  Should be under 20%, and preferably well under 20%!  The building code (IRC Appendix AS Strawbale Construction) requires that straw bale walls use bales under 20% MC dry weight.  There's a formula in the code for how to do that.  In a nut shell, select a handful of bales from the stack (randomly pulled from the stack--not all from the top, bottom, or sides).  Weigh each one, and measure the dimensions, converted into cubic feet.  Then measure the MC from a few locations on each bale and average the readings.  Subtract the moisture content weight from the bale weight to calculate the dry weight per cubic foot.  It needs to be more than 6.5 lbs./cubic foot and under 20% MC to be used in a straw bale wall.  

Wetter bales can take a long time to dry down, and are likely decomposing in the process.  If you're applying plaster (another wet material) to already not-dry-enough bales you're compounding the problem as now the bales have even more moisture in them and the plaster slows down how quickly they will dry out!  Lighter weight bales may compress in the wall, and won't insulate as well.  

We're typically using bales between 7.5 and 9 lbs. per cubic foot at 12% MC.

Jim
Many Hands Builders

John C Daley wrote:Your caution is critical.
Straw must be dry.
Perhaps look at this also;
https://www.buildingwithawareness.com/the-pros-and-cons-of-straw-bale-wall-construction-in-green-building/
The $500 you speak of, is that $500 more than $1000 or $500 more than $100, it is relevant?
Good luck with the build, can you post details?
Will you capture rainfall for domestic use, my signature has some information.

I ran some numbers and it’s an even smaller increase in price, so I’m probably going with the more dependable option.  

Yeah so it’s a small 500 sq ft 1 bedroom plus loft syp timber frame
Gable roof, that’s getting wrapped with bales, lime plaster on outside, clay on inside.  Bales will sit on a pony wall that is on a grade beam poured over a rubble trench.  That’s the short of it!

Thanks all for chiming in and confirming my suspicions.  I’ve concluded that this really is hay country, which I knew, but now on another level.  Not many grain farmers.  I believe this farmer is just cutting the rye he planted as a cover crop

I asked and it is still a bit green which I suspected, and still has grain heads.  I’m gonna go with another route, either the broker I’ve already found that’s further out, or I think I can find actual* straw closer in the next couple months.

Just wanted to follow up on this. Definitely passed on the “rye straw”.  Found a wheat farmer 2 hours from us that sold us bales out of the field for $4 a bale and loaded a uhaul using hydraulic bundler.  They used and old school combine that keeps the straw quite long.  It was a great solution.  

Bales were nice and dry and consistent size except for length which was fine.  

Also in hindsight rye straw seems much less substantial and maybe less tensile strength than wheat?  


Just wanted to follow up.  

We'd love to see pictures of the build and descriptions of your experiences building it!

I learn a lot from people actually doing things - and don't be afraid of posting mistakes as sometimes those are the most valuable lessons!

If you haven't posted pictures etc. before, there are how-to links in this thread:
https://permies.com/wiki/34193/permies-works-links-threads

Good luck on the building, and I'm glad you found someone with the straw you needed.