By Piers66
Surrey,
United Kingdom 
Should I add grass that's gone to seed to my compost heap?
I let most of my lawn go un-mown for the last few months, and it's gone to seed in the mean time. Apart from allowing some habitat for insects, it's stopped the soil from drying out as much as it would have done in the hot weather, which is a good thing!
As soon as it looks like the drought is ending, though, I'm planning on mowing it. Should I put the clippings onto my compost heap, or will that just mean that my compost is then full of grass seed?
8 Aug, 2022
Answers
I would be inclined to cut the grass now. Not too short but I think that the present dead matter could kill the underlying grass. By all means confine the cuttings to the compost heap and perhaps mix it with any other material you can find. It wouldn't hurt to water the heap to stop it becoming too dry thus speeding up the decay.
8 Aug, 2022
as owd says the seed will survive if the heap doesnt get hot enough.
as the thatch is providing shelter for the stuff underneath I wouldn't mow it until later.
But: make sure the dry grass isn't right up to house in case of fire.
8 Aug, 2022
My compost heaps tend to be predominantly grass already (and I suspect the poor green/brown ratio is why it usually takes a year (at least!) to break down properly).
They're also in a shady area at the end of the garden, so despite the weather having been so hot this summer I doubt they get hot enough to kill all seeds. Certainly when I've used my home made compost in pots a lot of weeds have appeared!
Don't worry about fires, the lawn is actually pretty small, and I mowed a border round the edge so that I could get at the flowerbeds earlier in the summer.
8 Aug, 2022
Previous question
Depends on how hot your heap gets to. Hot composting usually kills all seeds. Cold composting does not have that effect.
Personally I would add it and take the risk. Compost is too valuable to not use something.
8 Aug, 2022