An old trick with mint is to cut the bottom out of a bucket, dig a hole the depth of said bucket, put the bottomless bucket into the hole with just the lip above ground, then put all the dirt back into the bucket. That will keep the mint from spreading. If you want a larger stand, do the same thing with a storage tub.

I would dig the mint now, give away what I could, maybe save a little bit. Kill the rest with round up. Once the mint is dead, lay down some landscape fabric. Once the berries are done, harvest the runners and plant them in the fabric, this will keep the berries from getting out of control. Give away any berries you have left, or kill them with round up. You should still have time for some fall crops after the berries are gone.

No Round Up. I don't want to hurt the worms, the birds, or future grass. And I definitely would not use Round Up if I planned to eat veggies from a Fall crop, just a few months later.

I have read that it is possible to smother mint by covering it, so I'm posting in hopes that someone has actually tried it and has had it work.

You can kill off most things by just laying a tarp over it. Mow the area first with a lawn mower. Get a 12x12 tarp and cover the area , stake it down and forget about it till next spring. It will be bear ground by then. Also water the crap out if it before you put the tarp down so that anything that can germinate, will.

I have used this technique my self successfully.

Excellent - that's exactly what I was hoping to hear - somebody who has actually had it work. And I like that you suggested that I cover a slightly larger area - this stuff does travel, so it makes sense to also deal with any plants that are planning to sprout up in the surrounding area. Thanks so much!

Your welcome, now take a pic of it so you have a before and after pics so that others can see it

Stay away from roundup.

Five years later, I'm happy to say the mint is gone - but it put up a good fight. I had to cover it with newspaper and cardboard, and also put a tarp on top of that. It took 3 years for it to finally all die off. The old garden that had been there was moved, and now the area is just grass. It took a lot of patience.