Is it possible to dilute horticultural DE into a water solution and be able to spray it? If so, is it just as effective to use as the powder form it comes in?
Any ideas, let me know.

Yes you can and there are DE based products on the market that use that method. The effect as an insecticide is when dry, however. But getting it out there in a wet solution should work after it dries off. Is that how you wanted to use it? Remember that DE shouldn't be used around small animals as it can affect their breathing.

Kathe

I figured it was best used in it's dry state. But, when I was using it this morning around some areas where I have some ants the darn powder got everywhere. I thought "this would be a heck of alot better if it were in liquid form" and I could use a small sprayer to control it.
I appreciate the feedback!

I have another question: will DE hurt earthworms?
thanks, mary

No it will not hurt earthworms. I raise composting worms and have used it if I get ants in my worm boxes and it does not hurt them at all.
Richard Spitzer

No, it will not hurt earthworms. I raise composting worms and have used it in by worm boxes to control ants and it does not hurt them at all.
Richard Spitzer

Richard's right but let me add this little codicil. If you use it too heavily and it gets all over them it will have a drying effect so make sure they aren't in a situation where they're covered in it without enough moisture or other material to get it off.

I had a friend with a small child who managed to dessicate several of her earthworms once on accident. Mum wasn't pleased but she learned the lesson to watch the little boy around the bin. He was trying to help... as little children do sometimes. DE is a great natural product.

Kathe