Hay bale decomposition

Hey all,

I'm working on a project here, but need some experienced advice.

What does a hay bale left out in the elements (of southern Indiana) look like in 1 year, 2 years, 3 years?

How do to the ties (if it stays tied or if the ties are cut) effect the rate, and quality, of decomposition would you say?

It seems the bale gets much wetter with the straw standing vertically (so the rain can seep all the way down). This should speed decomposition right?

What are some low input additions to speed decomposition? Fungal inoculation? Compost tea? Light wood chip layer? Light compost layer? (not looking to spend a ton of time adding to these bales)

They will likely be sitting in a soggy clay loam field that's generally wet 6 months a year.

Help me turn this bale of hay into soil mounds to plant trees into!

I am ultimately considering putting wood in the middle of an arrangement of hay bales. A hay-hugel, if you know what I'm saying.

Thank you in advance!

The best success I have had (although not intentionally!) was to leave out a pyramid of hay under a hay tarp in the cow pasture. This soon became a pyramid with the tarp uncovered on the sides. And soon it was mostly untarped and partially consumed. Then as the stack started to get moved around, the edges became flattened compressed manured urine-soaked mats. soon this was true of the entire stack and through months of winter, a mound of compost steamed away happily (who knew cows were smart enough to build their own compost heater for winter months!)
...it would have been better had I removed the strings, but then again, this design wasn't really planned

IT DEPENDS!

Round or square?

Wire, sisal, or synthetic twine? or wrap?

Straw or grass or hay?

Tightness/density of the bale?

I have seen bales from the same field, time, and machine, stored side by side--only difference was the operator of the machine--that were so different in quality that one set was compost by spring and the other was still quality feed a year later.


There are things you can do to speed up decomposition if that is what you want. Pretty much the opposite of all the advice to make them last longer (DUH), plus inoculate them-put some forest soil on top and water/pee it in.

If you start with poor bales of a good C:N ratio and inoculate them I think they will be compost in a year. If you start with good tight clean bright straw, it will take longer.

R Scott wrote:IT DEPENDS!

Round or square?

Wire, sisal, or synthetic twine? or wrap?

Straw or grass or hay?

Tightness/density of the bale?

I have seen bales from the same field, time, and machine, stored side by side--only difference was the operator of the machine--that were so different in quality that one set was compost by spring and the other was still quality feed a year later.


There are things you can do to speed up decomposition if that is what you want. Pretty much the opposite of all the advice to make them last longer (DUH), plus inoculate them-put some forest soil on top and water/pee it in.

If you start with poor bales of a good C:N ratio and inoculate them I think they will be compost in a year. If you start with good tight clean bright straw, it will take longer.

They are square hay bales with synthetic twine. I couldn't tell you the density part with any great reliability over the internet, but let's just call it average. I'm encouraged to think this could only take a year! I will try a version without the twine and another version with the twine. I'll treat all if it with compost tea (have to get on making a few batches). With some success I hope to be able to plant the varieties of fruit that do not tolerate moisture. Another benefit is it will solve the "where do I get soil from?" question for hugelkulture.

George Meljon wrote:[Another benefit is it will solve the "where do I get soil from?" question for hugelkulture.

I did that for my first "swale" attempt, not digging just putting a row of mulch hay out. It didn't work as a swale but in 6 months it was reduced by more than 50%. The next year I did dig a small swale and then put logs on the swale berm and covered with more mulch hay. It looked good till the pigs got in to that paddock and ripped the whole thing apart!

You can tell the density by how easy it is to slip the twine off. If it slips off easily it's loose!

The wetter the straw the quicker it will decompose, peeing on it is a big help.

This will solve the "how do I cover the logs" problem of hugelkultur but not the "where do I get soil" one. Without soil added to the mix, decomposed straw is just compost. Sand, silt and clay are all a part of healthy soil. You can mix compost and soil together for a good hugel log covering. I know this from experience! Compost is not the same as soil.

Set them on edge, put good dirt inoculate on top (or use compost tea), water them until they start to drip out the bottom, pile them back into stacks about 4x4x4. As they heat up, restack them so the outside is in like the Berkeley compost method.

Keep them in the twine as long as you can, they are easier to move around that way. But if you break them loose and do a full-on Berkeley compost pile, you will get it done in 3 weeks. I would need the rest of the year for my back to recover, though...

Matu Collins wrote:You can tell the density by how easy it is to slip the twine off. If it slips off easily it's loose!

The wetter the straw the quicker it will decompose, peeing on it is a big help.

This will solve the "how do I cover the logs" problem of hugelkultur but not the "where do I get soil" one. Without soil added to the mix, decomposed straw is just compost. Sand, silt and clay are all a part of healthy soil. You can mix compost and soil together for a good hugel log covering. I know this from experience! Compost is not the same as soil.

The twine is too tight to slip off. On the ends the twine sinks in about 2-4 inches, so I guess that's good and tight!

I wonder if the root system of fruit trees would eventually find what they need of the soil about 2-3 feet down?

My first plan has the bales stacked three high (about 4 feet tight baled). The bottom two layers are like this _ _ _ and the top layer is perpendicular like this I I I across the top. If needed, I could remove a layer from the bottom, putting the height under 3 feet baled. However, if the twine comes off eventually (it will) this all figures to level down to the ground. Makes me think the 4 foot version will end up 2-3 feet finished. So, with that as a goal, is the soil close enough for the roots?

R Scott wrote:Set them on edge, put good dirt inoculate on top (or use compost tea), water them until they start to drip out the bottom, pile them back into stacks about 4x4x4. As they heat up, restack them so the outside is in like the Berkeley compost method.

Keep them in the twine as long as you can, they are easier to move around that way. But if you break them loose and do a full-on Berkeley compost pile, you will get it done in 3 weeks. I would need the rest of the year for my back to recover, though...

This is a creative way to work with the bales, I will try this as an adjunct to my project. Thank you!

We've had good luck running the rotten bales through a PTO manure spreader. You gotta use some sense, don't overload the spreader, you'll break it. Also, we piled horse manure atop the bale pieces, and the manure spreader beat it all up into pieces. Then we watered and made a 21 day "Hot" compost, or "California Compost, " as I call it.

We plant in bales of straw that have been inoculated with potting soil. We set the bales on edge so the water and soil will soak down into the bales. We lay a layer of soil on top and water till it comes out the bottom, repeat every two days for about 2 weeks then we plant the bales. In one growing season they deteriorate enough that we will move the remains to the in-ground beds and start a new set of bales. We grow leafy greens, squashes, cucumbers, peppers and tomatoes in the bales.