Unless you plan on getting the pile very hot you may get some sprout. Even if you get your pile hot you will need to be pretty active in turning it to make sure you sterilize all the seeds on the cooler outside shell of your pile.

grass clippings can get pretty hot. wet hay bails have burned down barns. right now there are lots of table scraps being worked by lots of black army fly larva. it's a black bubbly sludge.

I bit off topic but green grass is not a brown in the compost, it's a strong green. Dried leaves are browns.

If you were to add grass clippings and kitchen scraps to a tumbler, for example, you'd have all greens, and the result would not be particularly pleasant.

Fresh cut grass is a green. It does not take long for the nitrogen to burn off if left to sit for a whie. Which turns it to a brown.

Grass will heat up quickly but will also cool off quickly as grass tends to mat not allowing in the oxygen needed to keep the pile hot. You would have to be proactive in turning the pile both for the oxygen and to cycle in the seeds that are on the outside of the pile.

it's already mostly kitchen scraps & as I said it's a bubbling mass of sludge. the odor is surprisingly low level. also it's far enough from the house that it doesn't matter. if you've never had black army fly larva in your compost you have truly missed witnessing a marvel of nature. if they are sufficient numbers they can convert garbage to soil in days. it's too early for leaves. I was just hoping to make use of the grass clippings without planting crabgrass in my vegetable plot.

Sounds more like you are fermenting your kitchen scraps if it is wet enough to bubble. Also soldier fly larvae are good for some kitchen scraps but they are not as efficient as compost worms (red wigglers) and if you have bsf in your pile then it is much to hot for worms.

If the crab grass has seeds, even if not yet mature they will mature more in the compost pile and will produce viable seed there. A good hot pile, 135 degrees for a week, could be enough to stop them from germinating next year, however.

kimmq is kimmsr

it's too wet for worms too. I have a 2 bin tumbler. I rotate the use of the bins. bin # 2 has been dormant for awhile & is almost ready to use. I have 3rd tumbler as well. overall i'm not overly impressed with tumblers. I also have a separate pile for leaves. I think i'll put the seed laden grass clippings around my fruit trees for mulch.

Grass makes a excellent mulch. I use it in my garden all the time.

BSF are considered by some to be "The Ultimate Composter".

Green grass moistened just a bit will heat up all by itself. This may be a good time to try it w/o leaves that is. If you don't have a thermometer look for a gray ashen color in a day or two.

Just don't let it get overly wet even if you have to cover it should it rain. When too wet, not only will it not heat up but will turn into a slimy mess.

I remember describing these larva to another gardener a long time ago & asking what they were. she replied " I don't know but aren't they wonderful?" the temps. just dropped & the BSF activity has dropped to near zero.

Black soldier fly larvae eat vegetable and animal scraps but from my experience don't eat many leafy greens. That being said they are much more efficient then compost worms if you find yourself with lots of kitchen scraps. I just don't know if bsf castings are as nutrient rich as worm castings.