Brown ant problem

I'm sure this problem has been raised before so apologies if I'm going over old ground! (no pun intended)

The front lawn that came with my house when I bought it 12 years ago had several patches that had brown ants creating soil mounds. I've tried everything to remove them without success. Ant powder killed off the grass around them, as did boiling water from the kettle. I've tried removing the lumps of earth including the ant eggs where possible and re-seeding on fresh soil, still they returned. I've tried drowning them with water from the hosepipe and that had partial success (not all ant colonies returned the following year). Last November, in desperation, and because by now the lawn no longer looked good with all the patchwork repairs, I had the lawn re-turfed.

The men did a good job, rotivating the soil after the old turf was removed and putting fresh soil over the ground soil (which is basically clay in this part of Surrey). The new turf looked good. However today, when mowing the lawn, I saw that several ant-infested areas have returned. I can't say if exactly in the same places, but in similar places.

What's the current thinking on resolving the problem?

Thanks for your help.

 

I discovered through surfing the net last year that Borax seems to work. It's a natural substance but is poisonous. It's not available on the high street in the UK but you can buy it online which I did. I'll try to search for where I bought it from. It was relatively inexpensive, under £10 I recall for a tub that is clearly going to last me for years.

The general consensus online is that you mix it with something sweet which the ants are attracted to, put small blobs in areas that the ants are travelling around in, the ants eat it and take it back to the queen and they are all killed off over a period of time.

I mix 1 part borax powder with 3 parts jam (19p for sainsburys basics which they seem to like!). Last year I had massive infestations going on, one in the back garden, one around the front of the house, and one around the side. I'm pleased to say the side of the house seems to be clear so far this year, and I've just started dosing again at the front and rear.

Last night I was lucky enough to find a nest when taking two Silver Mugwort from a container, it was completely infested. I immediately surrounded the container with ant powder,and mixed a load in the soil in the container, and half an hour later there was no activity at all. I feel like I won a war! I'm hoping that this was responsible for the large quantities in the back garden but will still dose with borax. I am also aware that my herb pot is frequented with the b*ggers so I think I'll have to take that apart too and investigate.

Why am I feeling itchy again now!

 

I wonder, how do the nests get there in the first place? Is it the type of soil that attracts them (my soil is clay)? As an alternative to the given solutions by marley farley and debbiem for removing nests once they're there, is there any easy way to make a lawn unattractive to brown ants in the future?