A few minutes ago one brand food grade diatomaceous earth at Amazon was $1.99 lb and both Walmart and Home Depot were closer to ~$3 for their least expensive.

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And how much is Amazon shipping? Oops. $12 S&H for 10 lbs. Unless you have "Prime" of course.

Today Amazon shipping is free for orders over $25 for non-prime customers. This varies quite a bit.

That is orders totaling over $25, not just this one product.

Many don't bother to understand this. ETA it really is a bother. To get absolutely fee shipping one must click a box that says 'I do not want two day free shipping'.

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The 10# food-grade bag on Amazon I was looking at was $19.99. No free shipping. $12 to me for "Standard Shipping" (3-day delivery). No free shipping options available if this is all you're getting. Somewhat strangely, one-day shipping is only $10!

I posted this on another forum here, so I apologize for the duplication.

I discovered that DE is used in pool filters and called a local pool supply dealer. He had DE for $24.95 for 25 lb bag. This sounds like the way to go in the long run, but I ordered one of the smaller bags from Amazon to try first. I'm told that DE will take care of all beetles-bean, cucumber, etc. Unfortunately it will also get Lady Beetles if they encounter it, but I didn't notice any on the affected crops last year. I'll report back when my beans are in and up.

I'm suspecting that food grade DE is an unnecessary expense, and I suspect that pool supply DE is not food grade, which may make it cheaper. Does anyone know what is in NON-food grade DE that one wouldn't want to consume? I suspect it's nothing that will bother plants, and nothing that plants will transfer to humans as food.

On the other hand, I see it said that non-food grade DE is not an effective insecticide, for some reason. Everyone says that to kill bugs, you need food-grade stuff. Again, would be interesting to know the chemical difference.

I'm in agreement, Dan. It appears that some people do take DE internally as some sort of a system cleanse (but I know nothing about it) and for that I would want food grade, but I don't think he plants would care, but you would want to wash your produce well.

But lots of people say that you need food grade DE to be an effective insecticide. No explanation as to why. Sounds a bit fishy, and maybe a rumor started by the food grade DE producers!

I found a website that claims to explain the difference. Food grade DE, it says, is DE that you can safely consume! Thanks, um ...

ETA: the following is a pedantic comment about the definition of ''food grade'' and is not necessarily germane to gardening per se. An acquaintance of mine who has some familiarity with a diatomaceous earth mining facility says 'food grade', at least from this one facility, simply means it has less sand in it.

ETA; just checked. This facility harvests fresh water diatoms, specifically Melosira, or so I am told.

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https://www.tractorsupply.com/tsc/product/red-lake-earth-diatomaceous-red-lake-earth-with-calcium-bentonite-20-lb

Tractor Supply Co has 20 pound bags of DE for $13. If you have one around that's where I'd get it.

Rodney

So if you have sand in your DE, it doesn't kill bugs?? Whyzzat?

Re Tractor Supply, their DE is mixed with bentonite. So it isn't food grade. On the one hand, at least one of the reviewers says that they asked the folks there if it was good as an insecticide, and they said no. On the other hand, I sure wouldn't want to put bentonite in my garden! Bentonite is the stuff they make clumping cat litter out of. The clumps NEVER go away when you toss them on soil. They'll be there for years and years. I stopped using clumping cat litter a decade ago for that reason. It is entirely uncompostable. I still have clumps of bentonite out in my groundcover from a decade ago when I last used it.