Does First Saturday Lime Insect Repellent Actually Keep Bugs Away?

How First Saturday Lime actually deters insects

Here's what's actually happening under that white dust. First Saturday Lime is a very fine grade of calcium carbonate, ground down close to powder, and when you lay it across grass and bare soil it works the way lime has always worked in a barn or a coop: it pulls moisture. Ants, fleas, ticks, mites, most of the soft bodied pests that bother a yard, carry their whole defense in a thin waxy coat. Walk them through an alkaline dust like this and that coat breaks down, the moisture goes, and the insect dries out from the outside in. No nerve poison, no residue that needs a warning label, which is why it's rated safe around pets and food gardens; it's mineral, not chemical. The trade-off is built into how it works. Because the lime does its job by sitting on the surface and drying things out on contact, it isn't doing anything once it's not physically there. Rain knocks it down into the soil, a sprinkler cycle rinses it off the blades, and the yard is back to being just a yard until you put more down. That's not a flaw so much as the nature of a mineral dust instead of a systemic chemical, but it means this only earns its keep if you treat it like mowing and not like a one time spray. Once a month, maybe twice through a wet summer, and the barrier holds. Skip three months and you've got a bag of chalk sitting in the shed.