Compost grass question

[King Edward]

I have recently been scything down a lot of long grass in our 'meadow' area, resulting in a lot of dry grass containing tough dry stems of oxeye daisy and knapweed. Plus also a fair amount of tough nettles from elsewhere. Having added this to the compost heap, I'm concerned that it won't rot down that quickly because of not being chopped up finely enough (or not at all).

The heap is free standing and unenclosed under a small oak tree, so it gets morning sun but very little rain although I have been watering it. I tried mowing some of the cut material to chop it up, but this didn't really work, and there's too much to cut up by hand.

Can anyone advise how successful composting is likely to be with this type of material? Any helpful suggestions would be appreciated. I'll see if I can get some photos posted tomorrow.

[Cotham Marble]

Originally Posted by King Edward

I have recently been scything down a lot of long grass in our 'meadow' area, resulting in a lot of dry grass containing tough dry stems of oxeye daisy and knapweed. Plus also a fair amount of tough nettles from elsewhere. Having added this to the compost heap, I'm concerned that it won't rot down that quickly because of not being chopped up finely enough (or not at all).

The heap is free standing and unenclosed under a small oak tree, so it gets morning sun but very little rain although I have been watering it. I tried mowing some of the cut material to chop it up, but this didn't really work, and there's too much to cut up by hand.

Can anyone advise how successful composting is likely to be with this type of material? Any helpful suggestions would be appreciated. I'll see if I can get some photos posted tomorrow.

Clearly it will eventually breakdown - the question is how long, and whether that is a practicable option. There are two additives that I'd suggest using to help speed things up - nitrogen and lime, and because it's going to be difficult turning this material, adding the nitrogen and lime in solution is probably the best option. If you have a similar grass material in future, building a heap with intermittent layering (a bit like making a lasagne) with manure, top soil and lime on top of thinnish layers of grass is the best option.

I would also suggest topping the current heap with a thin layer of top soil and covering the whole with plastic sheeting to keep the moisture in. With luck in 6 - 9 months you'll have a material that you can cut with a spade, though I suspect it will still have stem structure -if you can cut and turn it, then after a couple more months it should be usable as a compost.

CM

[King Edward]

Thank you for the advice. Why do you suggest adding lime to the heap?

[Dorts]

KE. First I would say, not ideal having your heap under a tree. Plenty of daylight, air and moisture is best.

I would be carefull of using a plastic sheet to cover your heap. You need plenty of air in order for a good breakdown of fibres. Plastic sheets are used on silage heaps for example, to stop the rotting process, not encourage it!

I would mix as much other stuff, leaves, mowings, weeds, etc. as you can to your coarse material. Then, (I know it's hard work), but move your heap as much as you can, treading it down as you go. Two or three times over the winter would help. This will stop too much compaction and introduce air, ang get it to heat-up again. If you do this you can break-down anything, even small twigs and the like, and you won't need to add anthing extra.

Leave over the summer and use next autumn.

I spent many winters as a lad, when doing my horticultural apprenticeship, moving compost heaps; a few yards this way, then a few yards that. It was hard work, but we produced wonderfull compost, and absolutely everything you can imagine went on those heaps.
Best of luck.
Dorts.

[King Edward]

Thank you, Dorts, for your opinion. The position of the heap under the tree is actually very convenient, and it does actually get a fair amount of direct sun and air while being sheltered from the prevailing wind (which would be pretty drying), it just doesn't get much direct rainfall so I have been watering it. I can't really think of a more suitable place for it, but in any case I'll probably have to start a new one once it outgrows its current area.

I have been including the various materials you mention (weeds, fine mowings etc.), and avoiding really coarse woody stuff like brambles, but just at the moment there's a lot of the dry grass about (and more to cut).

I'm also hoping to get laying grass snakes so don't want to disturb it more than necessary, at least not at this time of year - I spotted one female by the heap back in June, but don't know if she laid there or not. Wasps have also taken up residence at the base, so again I need to be careful there.

Essentially, I'm not too worried if the composting takes a bit longer than under ideal conditions, just so long as the end result is reasonable.

[Dorts]

It's interesting you mentioned the Grass Snakes using the compost heap for egg-laying.
The heaps I refered to earlier, always had old Grass Snakes eggs in them when we came to use it in the autumn, sometimes several lots.
Any disturbance via the turning of the heaps was completed by Feb/March, so there was plenty of time and just the right amount of heat left to encourage them to use it for egg-laying.
Also great places for invert's to shelter along with mice and voles etc..
Every house should have one!
Dorts.

[King Edward]

I'll probably leave it relatively undisturbed, except for the addition of new material on top and at the sides/ends, until some time in the mid/late autumn and then see how it looks. Quite likely Toads/Frogs may also take up residence, being quite a lot of them around here, so I'll need to avoid skewering them.

[Cotham Marble]

Originally Posted by King Edward

Thank you for the advice. Why do you suggest adding lime to the heap?

As the heap compacts, because of the nature of the material, anaerobic processes are likely to lead to acidification which may in turn slows the process of decomposition; adding lime reduces this effect.

I agree with Dorts' comments, excepting that what you described was a very particular material - 'thatch' rather than silage, and the microbial enviroment differs greatly between the two. In a properly maintained silage clamp - the material is heavily compressed to exclude air - the main activity is yeast driven and the grass is 'fermented'. In compost heaps the main activity is usually bacterial, with aerobic activity usually preferred because of the lack of bad smells; with your 'thatch' heap the likley main activity will be fungal, which may be somewhat slow and has problems of atomising high spore volumes when handling - Farmers Lung .

Adding nitrogen 'feeds' aerobic bacteria, adding top soil introduces additional bacterial populations, and lime helps keep the environment comfortable for the aerobic bacteria. Keeping the heap moist (but not overly wet) again helps keep the environment suitable for aerobic bacteria. Absent of grass snakes - a loose, dry heap can attract rats, but it sounds as though that's not an issue in this particular case.

CM

[King Edward]

Yes, the potential problem with high spore production was something that I was concerned about, so I'll continue watering the heap to try to keep it moist. I don't think overwatering is likely to be a problem, since the material is mostly quite loose and free draining.

[Hobjob]

I am no expert - but I can remember being told that it is best to get the cuttings off the meadow, as you want it to remain nutrient poor, and the composting nutrients will leach out into the meadow.

I know that adds to the work though

I can think of two local fenns that leave it in piles because of the work involved and lack of limitless workers

Perhaps the exerts would comment?

Cheers