ant, ants, ants
I have raised garden beds made of pressure treated lumber. While preparing a bed to plant I discovered that it was full of ants, those tiny little sugar ants. I sprinkled the bed with a combination of Borax and Grits. That was two days ago. The ants are pretty much gone. My question is how soon can I plant that bed. Or should I leave it dormant for a season. It's not the grits I'm concerned about, it's the Borax.
The most important factor is to determine how much boron is in the bed because the range between boron sufficiency and toxicity levels is very narrow. Excess damages plants.
Where soil is boron-deficient in Oregon, the amount to add is very small. Directions say “to dissolve 1 tablespoon of borax in 1 gallon of water and apply the solution evenly with a sprinkling can” to 100 square feet. In other words, a minimal amount. (See page 4 in Fertilizing Your Home Garden http://extension.oregonstate.edu/polk/sites/default/files/MG_Handouts/ec_1503_fertilizing_your_garden_0.pdf .
The only way to determine how much boron is in your raised bed is to have a professional lab test. So, I suggest you have the soil tested by a professional laboratory. Be certain to explain what you did and what you want to grow. Also request the lab include recommendations in the report of what to do. Contact A & L Western Agricultural Laboratories at 503-968-9225; the cost of a basic soil test is about $35 or so.