Ant invasion in greenhouses.

[greenishfing]

In two of my greenhouses I plant directly into the border soil in a slightly raised bed. There is a line of stone flags running from the door up the centre. Both of these greenhouses are overrun with ants which are preventing me from weeding and working. The greenhouses are home to tomato and pepper plants which they are not climbing. The main reason I want rid of the ants is that when I try to work in there they try to crawl all over me. I have tried putting lots of water down any visible holes. I obviously don't want to harm my plants. I suspect the nests might be under the flags but I can't lift them until the greenhouses are empty. I have tried various so called deterrents: lemon, mint, cinnamon to no avail. Has anyone any suggestions?

[Plot70]

I use a spray can down the holes as long as they are more than a foot from the plants.
That white powder only works if it is pumped into the holes with compressed air so it is a waste of money.
If you can expose any eggs spray them as the ants will take them into the nests.
Have they done much root damage to the plants?

[burnie]

I have a few ants in my greenhouse and asked a similar question last year, I have just ignored mine as they don't seem to be a problem for me, would wearing gloves improve things?

[MarkPelican]

The ants are unlikely to attack your tomato plants because of the Tomato Tar on the stems (it sticks to their feet). I get ants early on in the season and I use ant nest killer (either powder or liquid) and they seem to go away.

[ameno]

Nest killer granules or bait stations are you best bet if you really want rid of them.
Unlike the powders and sprays, they are formulated not to kill instantly. That way, the ants take the poisoned bait (it's sugar) back to their nests, where it kills the whole nest.

[MelanieSW]

I haven't tried it yet, but you can get nematodes against ants. They don't kill, just deter the ants so they they move on. Looking to try that next year in the hope that it will help to reduce blackfly infestation.