Zone 5b…very dry season so far. I have a space that has had black plastic on it for a few years, it is now weed free except for something that is still producing rootlets and some growth that reminds me of blanched asparagus…but 98% clear of weeds. I have taken the weed whipper and buzzed the surrounding 2 feet down to the soil just to try to hold back the nasty mix of tough grasses and goldenrod etc we have here. I’m going to rake it and seed it today…a lot of work unless you have power equipment !! It’s about 55 by 32 feet. Aside from keeping well watered for the first few weeks, does anyone have any suggestions ? i hear that many seed mixes incorporate rye grass or such to help create some early growth and shade to help keep things from getting parched and help the wildflowers along…any thoughts ? I’m not sure whether I should go along the edges with strips of black plastic overlapped into the cleared area and the border to try to keep back the weeds from invading…also wondering about seeding the perimeter with buckwheat to try to keep back the weeds. Anyone with experience establishing a wildflower meadow ?
I wouldn’t add ryegrass unless you want it around permanently. Oats are commonly used here when establishing wild flower plantings.
I’m no expert on the subject, but right now wouldn’t be the time of year that I would try to get wildflowers established. I have about an acre of wildflowers. I burned the area down with glyphosate and 2,4D a number times from spring through fall. I then spread the seed in mid December before a snow fall. It worked quite well.
Good luck with your planting. Wildflower meadows are beautiful
what would be the difference between rye grass and oats ? I mean, aside form one being rygrass and the other oats 
Ryegrass is a perennial. At least perennial ryegrass is. Annual ryegrass is an extremely heavy re-seeder and again…once you have it, you are going to be stuck with it.
Oats are a grain. Having them re-seed themselves is relatively unusual due to the seed being much larger than grass seed.
Winter rye (not rye grass) would be another option as it’s a grain. However, fall planted winter rye doesn’t terminate over the winter. It vernalizes, and puts on huge amounts of growth the next spring/summer. It tends to re-seed itself more readily than do oats, but getting more than a single “free crop” of rye is not all common.
I must have been thinking of winter rye, the grain…i read that it is often mixed in with wildflower mixes to provide ( i think ) some fast growing shade that i believe is supposed to be a nurse crop for the wildflowers and help them get established…I am just out preparing the area today and I believe it is my septic field and the soil is quite sandy, I am concerned it wont hold water…I may sprinkle straw and cut grass over to make a bit of shade mulch to avoid the earth getting parched…we have some rain in forecast for tomorrow but mot much else…I dont really want to hold onto the seed till the fall because of viability, plus i would like to get something started and reseed… I also have a small bag of winter wheat here on my kitchen table…which i think i got for wheatgrass
So i just read that winter wheat will also persist and possibly be toxic to other plants, so that’s out…oats it is !