You can still use it as mulch. If that material got hot enough any "weed" seeds in there would have been cooked.

The mulch heating up like that is quite common when green leaves are mixed in with wood chips and I have even seen piles of just freshly cut wood chips heat up like that.

kimmq is kimmsr

Sounds like you have a big pile of material that is composting. What are you mulching? Like paths?

Lloyd: We were using it as a weed smothering device underneath established trees. The ground below was covered with scraggly grass, thistle, burdock, nightshade, creeping charlie, you name it. So we hacked all that down and put down cardboard/paper over it. Then we layered this stuff over it to look prettier than just a sheet of paper under our trees. Except it just looks like a bunch of lovely black dirt under our trees now.

i wonder if this compost layer will simply foster the genesis of a new generation of weed seeds that love their new rich bed! Maybe I can sprinkle some perennial native prairie wildflower seeds in there this winter to get a jump on it.

also, will this compost be any good? I thought compost was supposed to be made of fall leaves and grass clippings, not wood.

Compost is made from any organic materials you can get hold of - wood included. There is no 'correct' recipe. Sounds as if your pile had a good mixture of wood and leaves to get it decomposing nicely.

You have really awesome compost is what you have, better compost than you could buy in most garden stores, and just as good as compost produced from a home pile or bin with a LOT less work. I am officially jealous of your awesome compost.

If it got hot and stayed hot, in all likelihood the vast majority of seeds will be destroyed. There are parameters for time and temperature but I'm too lazy to look them up. Suffice to say heat will render most of those seeds nonviable. As for the weeds you had, those are pretty tough weeds. I've had little luck (by little I mean zero) getting rid of burdock and generally resort to chemicals. I tried an experiment just today with cutting down some burrs and treating the cuts with a 50/50 mix of Roundup Transorb. These were pretty healthy plants over six feet tall with a stem diameter of about 1.5 inches. But I digress. If you are using this new stuff (it ain't compost yet) as a smothering mulch I'd say you're good to go.

will this compost be any good? I thought compost was supposed to be made of fall leaves and grass clippings, not wood.

It should be awesome. What you have probably has dry branches, dry leaves, green leaves and fresh twigs and sap-filled bark, all chopped and mixed together. Some of my best batched of compost came from nothing but shredded trees and bushes.

As Floral UK said, there are no official recipes** - use what you have.

** the only real "rule" in composting is that you can't put too much high-moisture material (grass clippings, vegetable trimmings, etc.) in the heap in one layer because of goes anaerobic and stinky. And if you live in bear country, don't add too much fruit or they will raid it and wreck it.

This stuff is ideal for putting on top of that cardboard. I was going to say if it's hot it could possibly stress plants (especially smaller or tender ones) if used as mulch, but for soil building in such a place it's perfect.

I would lay it on thick as it's partially air and will sink down, plus it will decompose. Use several inches - 4-6" is not too much.

When it rains the black composted part will wash down into the layer leaving remaining wood chips on top.

You done good!

Thanks everyone! By the way, how long does cardboard tend to last in the garden? Actually the materials I used were a combo of cardboard boxes and extra large leaf bags I unfolded. If the mulch is weedy, or even if it isn't, how long before the underlying weeds break through and it needs another applications?

I have a wet climate and cardboard breaks down in a couple of months under mulch. Big pieces like boxes for fridges, etc. last longest as they don't have so many edges for the moisture to penetrate.

I have created several planting beds using layers of newspaper as well as cardboard and leaf bags and have found that the grass and other unwanted plant growth was mostly digested in about 6 to 8 weeks. The newspaper, cardboard, and leaf bags were mostly digested in 5 to 6 months.

How long it took some of the more invasive of those plants to grow up again depended on many things, but mostly it was well over a year.

kimmq is kimmsr

Hm. Do you think bulbs will be able to come up through the paper in the spring? Pretty sure I covered up quite a few in the process. Tulips, grape hyacinths, alliums...

If you put the paper down now it will be pretty well digested by next spring when the Tulips, hyacinths, alliums, etc. start to grow, unless the layer of paper is like 4 to 6 inches thick.

kimmq is kimmsr

I noticed that some cardboard in garage that had stayed continuously wet for a few weeks at most had degraded to be so soft it was barely there. So a good soaking at some point will also help. If your winter has snow or even some good rain and it gets natural decomposition, I seriously doubt it would interfere with bulbs growing.

Note that since bulbs will be able to pierce it so will the more tenacious perennial weeds. There is necessarily a compromise if you want your bulbs to grow. I have cardboard and mulch around my soft fruit bushes and while it is relatively weed free, I do still have to keep an eye open for bindweed, enchanters nightshade, couch grass and crow garlic.

Yes up in Wisconsin we get a ton of rain and especially snow, so that is encouraging. Lots of bulbs have naturalized and I'd hate to lose that pretty spring show. That being said, so do you guys mulch and cardboard/paper your beds once per year? Since we get this mulch/compost stuff, that is a "can do." i guess timing depends on zone, but perhaps the best time to Paper and mulch would be after the green shoots of the spring bulbs have died back in early to mid summer. Does that make sense?

Mulch every year is good for the soil, but the paper/cardboard is only necessary when initially covering up existing plant growth like a lawn, to make sure it is killed and doesn't come through.

Hey floral, I notice that you mention couch grass. (I am currently in the process of 'getting rid of it'. I do this on occasion. Then I simmer down and let it run riot.)

Do you think it's the same thing as Bermuda Grass?

Just wondering.

Bermuda isn't hardy over here. Our couch grass is Elymus repens. A rhizomatous hardy grass. I have a bit of couch on my allotment but it is nowhere near as troublesome as the Bindweed, Calystegia sepium.

Just looked on wiki and your couch looks different to our couch.

I've just done some googling and it seems that our couch is Cynodon dactylon.