Reconsider composting - it's what Mother Nature uses :)
Maybe increase the frequency in which it is applied. Once you observe the benefits of compost & organic matl. in the soil & your healthy plants you won't want to use anything else

One of the roles/purposes of mulch is to help prevent weed growth. Another is moisture retention(Prevent drying by evaporation).
With regard to those two , I would not use compost, Because it is very close to soil, to begin with.

My favorite mulch is (used to be in GA) pine needles. In the absence of PN, I like small pine nuggets. Both of those, when decomposed, become a good soil conditioner. Wheat straw is also very good but hard to find. I used grass clippings past summer but did not like them. Especially with our rainy cool climate, it will be just too MUSHY all summer long (even after sun drying them) . Black plastic is good,depending on your temperatures and the amount of sunshine on it. Obviously, you wouldn't want to use it down south.

I cannot understand how grass clippings caused grass to grow in your beds unless you don't mow your grass until it is completely seeded out. Generally grass is cut when it is a few inches high--no seeds in that. I suspect that you mulched too thinly and seeds blew in from elsewhere. Mulch needs to be thick, and grass clippings make excellent mulch if you have enough.

However, do be aware that removing the clippings from your lawn inevitably will lead to your lawn going downhill.

I like dried grass clipings and straw that I've run over with the lawn mower and collected in the bag. Straw is just too long to strew among the plants if you don't chop it up a bit first.

Lots of 'favorite mulch' discussions here and even more over on the Soil & Mulch forum. Several contain long lists of things to use for mulching and plastic/landscape fabric isn't very high on the list.

While plastic mulches can work ok on some crops it's is only on specific crops (like melons) and in the northern zones where soil warming is required. And once full summer arrives it can cook the plant roots unless removed or covered.

I agree with lacey that you must have been mowing grass that had gone to seed or a lawn with lots of weeds that had gone to seed. Pretty hard to get seeds from grass clippings otherwise.

Straw, chopped or not, is often touted as the perfect mulch with old hay and compost close seconds. Other good alternatives are leaf mold or shredded leaves, cardboard, newspaper (shredded or multiple layers), pine straw, etc. but regardless of what it used it has to be applied thickly to work and to remain in place.

All of those have the added benefits of soil improvement. Plastic doesn't contribute anything to the soil.

Dave

We have a large, hilly yard and my husband works 60-80 hours a week... I'm not skilled/confident enough to handle the steep slopes with a riding mower, so yes... the lawn doesn't get mowed nearly as often as it should. I often pull tall, seeded grass by hand from around the planting beds and other areas that are hard to reach with the riding mower (we're finally getting a trimmer this year). When I did try mulching with grass clippings, I tried to make sure there weren't any seeds mixed in, but it was just too much trouble.

I hadn't really considered straw, sounds like that might be a good option for me.