[old dave]

Hullo, can anyone advise me on getting rid of ant nests now established in the polytunnel in an humane organic way that's not going to poison the soil (or us)?
I've tried baking powder and coffee grinds to no great effect
Thank you

[Beekissed]

Try setting out small containers of corn meal...we use lids or tuna cans.  It works wonders for the standard black ant that invades the home, so it may work for your ant type there as well.  They take it back to the nest and consume it and feed it to the young, but the corn is corrosive to their digestive systems and they all die from it.  Takes a few days from the time they find the corn to see the results but this works for us every year. 

[AlaninCarlisle]

Isn't that being cruel to ants? I prefer the quick humane way with ant-killer poison

[Beekissed]

Yes...because dying by poisoning is so very humane...      

[8doubles]

A couple of kettles of boiling water sorts shallow nests.

That or flood em out , they dont like it too wet !