I haven't tried seed mats, but you could try solarizing the beds if the area is in full sun so that many of the weed seeds are killed. To do that, clean up and level the bed, water it, and cover with thin clear plastic sealed at the edges with boards, rocks or burying the edges and leave for 4 to 8 weeks. Then remove the plastic and plant the annual seeds, preferably without disturbing the prepared bed.

Thanks nhbabs for the suggestion. Worth a try.

I'm thinking the seed mat would eventually allow weed seedlings through anyway. Since I bought the packs, I might as well use them in the conventional way.

I bought 3 of the mats on sale for $1 each during last year. Waste of money. They won't germinate if you do as instructed. (I checked on amazon for other opinions and none got them to work)

The main problem is they do not hold any moisture - you'd be watering them all day long. Also I think if weeds can't get through how can flowers get roots down through?

I tossed soil over them and got one small piece to germinate. Only the alyssum and black-eyed susans though.

Last year I also made wildflower gardens with the cheap seeds and mixes in a can from the dollar store. Worked great and I was even a beginner, and checking the brand, they don't even do pesticides / gmo. I'm not sure why a lot of gardeners don't like them.

The flowers didn't allow many weeds to actually grow, I guess too thick to allow sunlight to the weeds. If you buy seeds too you can sow them evenly which makes it easier to tell a weed. I didn't do anything really though other than dig the weeds / grass under before throwing down seeds, just let the flowers get big and pluck the odd wheat-like grass that came through.

Thanks, that's what I needed to hear kitteh. I'm not going to order the $20 seed mat. :)