How many pots are involved?

No it wont work as soon as it goes out into the cold the nematodes will die.

You will probably have had the vine weevil in amongst the plants that you put into the pots. So annoying.

Half a dozen pots.

i'd be tempted to empty them out check all roots and then repot in fresh compost.

I usually hand pick out all weevils I can see and feed to the fish. then I spread the 'infested' compost on the borders and let the birds have a good rummage.

Hi Amsterdam, so sorry to hear that you have this dreaded problem. My wife and I suffer annually with this problem. We usually resolve it by tipping the soil from the pot or container into a wheel barrow and sorting through it. We then start again with fresh soil/compost. Like Seaburngirl we let the birds have a rummage through the soil in the wheelbarrow, them blend and re-use the soil at a later date. I wrote a blog relating to Vine Weavil in an Acer pot, 25th May 2014.

You may find it of interest. A link to the blog is attached below.

https://www.growsonyou.com/alanb/blog/26547-vine-weevil-eats-potted-acer-roots

Good luck.

With only half a dozen pots repotting with fresh compost would probably be safest - examine the roots carefully before adding new compost. (Nice idea to leave the contaminated soil for the birds to poke about in!) (Sorry Eileen and Alanb for duplicating your advice, but as I'd asked how many pots thought I'd better reply to the question as well)