Are they fire ants? How large are the containers? Do these plants live in the greenhouse all year, or did you bring them in there for the winter? Do these plants sit on the floor of the greenhouse? And is it a dirt floor?

You have several options but further information is needed.

Go to a hardware store which sells insecticides. Buy Cygon. It is a systemic insecticide, so it is safe to mix and pour around your plants roots. It will kill the ants. I used it today. I watered everything in the greenhouse with it to control spider mites, plant lice and mealy bugs. I use it on tropical hibiscus all year long.

Terry

Thanks everyone. I have been so busy with the new grandbaby that I haven't been back online. Hey Terry how long does it take to kill them when you water. Is this something you also spray on your plants?

Cygon can ne used as both a spray and as a ground soaking systemic. The ants in the ground will be dead within 24 - 48 hours if you pour the stuff on them. I warn you, this stuff stinks. It's like the Loudon Wainwright, III song from the 1970s. It smells like a Dead Skunk In The Middle Of The Road.

Good grief! Cygon has been yanked off the market for ALL residential uses. It is a very hazardous product and has no use in the enclosed environmental whatsoever. TSmith, if you are smelling the stench of a chemical such as this, you are absorbing it into your system. Inhalation is a primary pathway into the mammalian body.

Good grief.

Here is a link that might be useful: Cygon withdrawal

OMG, I love Cygon. Been using it for years. It is so good. Stinks to high heaven, but effective. What can I use to replace it. I better go down to Lowe's to see if they still have some in stock.

LOL, Terry! So THAT'S what's wrong with you all this time! (Just kidding)