they really should be mixed with some browns (leaves, newspaper, etc).. big piles of clippings will decompose, but will stink like ammonia and likely turn into a icky thick sludge if you don't turn frequently.
if you don't want to compost them with browns, you're probably better off spreading a couple inches on the garden as mulch and letting them decompose that way.

It's up to you whether to accept the clippings but keep in mind that you are basically accepting everybody else's garbage and weed seeds. My brother who had a farm in a subberb area accepted clippings and they were riddled with paper litter, hedge clippings and who knows what else. I would start this agreement with a few ground rules if you proceed.

You'll be shocked at the stench of piles of decomposing grass clippings.

Another problem associated with lawn clippings is the chemicals that are so commonly used on lawns. Herbicides, fungicides, and insecticides of all manner are used in enormous quantities, as well as high nitrogen fertilizers.

These chemicals are adsorbed and absorbed into and into the grass, and are a part of the clippings.

On a vegetable garden? No thanks, no way!

(The best thing that your lawn guy can do for you and his other customers is to add mulching blades to the mowers, which cut the blades into such tiny pieces that they can be left on the lawn to decompose in situ. That's a very good thing, as long as mowing is done on a regular schedule.)

Just adding enuff water to dampen the grass clippings will be enuff to heat it up. Certainly you can add leaves, paper, or other carbon materials but grass clippings alone will compost just fine with the right amount of water.

I prefer to use rainwater as the chlorine from tap water can inhibit the very bacteria you are trying to grow. Or leave some tapwater out overnight in something like a 30gal trash can to allow the chlorine to dissipate.

If you decide to give this a go a compost thermometer can be very helpful to see when the pile is heating up. But it should be heating up a little each day. IF after a day or two you see a gray ashen color in the middle of the pile - that is heating up.

You should cover this pile up if/when it rains or too much water can slow things down or turn it into a slimy pile as mentioned but that is from too much water. A trap will work just remember to remove it after the rain to allow air into the mix.

Air, water, and organic matter are important to the composting process. Not enuff (or too much) of one or the other throws things out of balance.

Also as mentioned you may get scraps of trash or weed seeds you don't want but generally speaking the heat of the compost will kill off weed seeds.

The trick is getting the outside of the pile turned in so it will also heat up. Harvest the compost from the center first - add compost from the outer part to the next HOT pile to kill off those seeds.

Depending on who is providing these clippings you can end up with some invasive weeds also.

HTH

Just be careful that you don't get clippings from someone who has used herbicides on their lawn. Even after the herbicide-laced clippings have decomposed, they can still affect your tomato plants :-(.

Linda

You could also spread them out, rather than piling them & once they're dried out, then they could be piled & turned often enough to aerate & prevent the stink.

Certainly you don't know what others spray on their lawns but will they spray things to kill their grass? Also I would think that any herbicides available to the homeowner today would be neutralized by the composting process.

But hey IF any of that herbicide or weed seed thing make you nervous then don't get you compost from the town who will certainly have some of the nastiest unknowns dumped into it.

Or how about you buy the store bought stuff that you have no idea what went into it?

I have seen shopping centers contract landscapers who put down mulch that later sprouted some on the nastiest invasive weeds in the area like bittersweet. But who knows where the landscaper got the mulch from?

And if you know landscapers looking to drop some woodchips for you - FREE - NO Charge then you can get some invasive weeds that were growing on the trees they just chipped.

My point is IF you make your own compost you will at least know exactly what went into making it even if it is grass clippings from someone else.

Thanks much for some excellent advice, folks. I'm embarking on an adventure. A horse ranch has almost unlimited supply of aged horse manure. Looks like I can achieve a hot compost and avoid a smelly mess, after all.

as long as the pile heats up don't worry about weeds as they will be generally be destroyed.. as for grass treated with herbicides.. these days, most herbicides are a lot safer than in previous years and won't survive in a properly heated bin.. as long as some times elapsed since it was treated, but your best bet is to asked if it was treated and the type of herbicide used.

But isn't aged horse manure also a green? Even if it looks brown? Hmmmm. Nancy

I thought the very same thing. Since I have not composted manure I wanted to wait for someone who knows better than me.

Horse manure (a green) mixed with grass clippings ( a green) could make a mess.

I do know you can just add water to the grass clippings to get it composting hot. Already had someone here who didn't understand that recipe.

Now, I'm on the defensive. The aged horse manure is composted horse manure and straw. That's manure and browns, right? So, logically, I'm layering greens, browns, manure, right? Anyway, 24 hours after receiving the grass clippings, I reached into the pile and felt the warmth. Also had the greyish color signalling the pile was beginning the cooking process.

<Anyway, 24 hours after receiving the grass clippings, I reached into the
pile and felt the warmth. Also had the greyish color signalling the
pile was beginning the cooking process.> And thats all it needed - simple as pie.

<Now, I'm on the defensive. The aged horse manure is composted horse manure and straw.> 1st don't be on the defensive. I did say I've not composted manure before right? So I'm thinking if you have <horse manure and straw.> then you have the right mix - again just add water, no?

Then I also have to ask IF <The aged horse manure is composted horse manure > is indeed already composted why would you have to compost it again? Or why would you want to?

Is that like the "twice baked potato"? <smile>

I started a hot compost pile with grass clippings and aged horse manure compost. Or, I continued the aged horse manure compost pile by adding grass clippings. So, John Deere riding mowers might have a bag to collect grass clippings. That bag is something like 3'x3'x3'. That's a lot of grass clippings. I used about 40% for the pile. Any more, and it would be unmanageable for me. The rest I spread out to dry. Once the pile works for awhile, I probably can add the dried grass a little at a time. And, yes, I'll not be doing a hot compost as long as my horse manure compost resource is available. :)

Yes that bag should heat right up for you - quick n easy. You could add some worms to the composted horse manure if you are up for it. Or just wet it down some and hopefully the red wigglers will show up for you.

> But isn't aged horse manure also a green? Even if it looks brown? Hmmmm. Nancy

fresh it is both. even if it's aged (composted) it still has a lot of carbon, but it has a lot of beneficial bacteria which when added to a compost bin will accelerate decomposition of what it's being added to, so it makes an excellent compost starter/activator. it has just about the perfect carbon and nitrogen ratio, so horse manure can even be composted alone.. i currently have a bin of just manure and it's composting nicely with no added browns.. you'd think a pile of crap would stink, but absolute no foul smell.

there are tons of horses around here and i get the stuff for free. recently visited a ranch that had a pile of composting manure.. stuck pitch fork in and was surprised to see there were hundreds of thousands of red wigglers.. its win-win.. get horse manure and take some of the worms to make a bin for worm castings.

I have a big pile of grass clippings next to my 3 bin compost area. When I put kitchen scraps into the active bin, I top with a layer of grass clippings. I also edge some of my vegetable beds with wet newspapers topped with grass clippings. This helps keep the weedy grass from getting into the beds. I have had access to cattle manure that has too much sawdust bedding mixed in so it needs to break down. I prefer horse manure. The best aged horse manure I used to get had kitchen scraps and bedding mixed in. The owner turned the pile during the winter so it was nicely composted by spring and could be put right on the garden. I've dug into a neighbor's pile of grass clippings to find the stinky stuff but my pile tends to be on the dry side. Not sure why. BTW I was thinking of asking the tree trimmers who work for the power company to dump a load of chips at my house but one time I saw a crew going through a large mass of Japanese knotweed which got mixed in with the wood chips. Ack!