I have mixed them with no problems.

It is never a good idea to mix two different products without good research to see what the reaction would be. What would the Neem do to the bacterium that is the Bacillus thuringiensis? Would the Neem kill these bacterium? Render them less effective? What will happen? Is there s synergistic affect that causes this mix to be something more potent that now kills off many more species of insects, including beneficials?

kimmsr brings up a good point. I've contacted the U. of Fl. agricultural extension with this ? and will post their reply.
I have found that it is often necessary to apply BT more often then weekly in times of frequent rain. I like to keep the dust form of BT, Dipel is one brand, on hand as well as the liquid form. It is often quicker for me to dust between rains than to mix up a tank, spray, clean the tank, etc. This has helped me control caterpillars in the rainy season and maybe it will work for you too. Just my 2 cents. Good luck in your bug war.

works fine. Neem and BT are compatible. Don't stress over the details as neither is a reactive chemical so just mix and spray and don't worry about it.

Those who wish to over caution can continue to have poor results year after year.

I seldom find a reason to use either anymore, occasionally some BTK for Tentworm caterpillars, because I seldom have pests. If you have a good, healthy soil your strong and healthy plants will resist attack by both plant pests and diseases and you will not need to concern your self with these remedies.
Work on getting your soil into that good, healthy condition and spend less time worrying about the pests.

Thanks Peggy and Justaguy. Hopefully there is a responce back from the university.
Kimmsr,
I am trying to build my soil but I still want to get at least a little Harvest in the mean time. I only moved to this property 9 months ago so the soil building takes time. Some of the ground around here was bare sand. It will take some time before my soil becomes healthy enough to protect my plants from sub-tropical numbers of pests.

Did you try your county/parish agent? Sometimes you can get answers soon,

Mixing Sevin and Diazinon can kill you.

Kimmsr isn't going to like this, I use an old tobacco juice formula that will take care of all the bug problems.

Tobacco can kill you too, perhaps why it works so well on bugs.

Hay, thanks peggy!!!!
Actually, you are not supposed to let either Neem or BT alone sit in the tank after mixed so it seems pretty reasonable not to let the combined mix sit either.

This is great news as spraying takes quite a long time and trying to spray separately was becoming way too much with all the other garden chores.

I am so looking forward to the day that the soil starts helping me out a little and I get some population of beneficials.

I've been catching critters so I can try and look them up to identify what I have. Easier said than done though.

You are not supposed to let anything you mix sit in the tank. Once done spraying you are supposed the rinse and clean that spray container and let it dry.
The best pest control is a good, healthy soil. While it will take time to take any soil that has been gardened "conventionally" for years to build up the Soil Food Web needed for a good healthy soil and some means of pest control will be necessary until that time comes, due care should be used. There is no sense in simply subsituting one set of poisons for another.

For small gardens a spray bottle like window-cleaner comes in works good. So much easier than bothering with a spray tank and hose. I mix a little dishsoap in with bt to make it stick to foliage better.

I've learned to be careful with the dishsoap. With the intense sun and heat around here some plants are rather sensative to it which then means washing the plants off afterward kinda defeating the purpose. Anyway, I have to many plants to make squeeze bottle application effective.

Last time I sprayed BT I went through 3 tanks worth. I'm definitely looking for some of the BT dust to see if it is any easier/more effective.

Anyway, I am trying hard to use methods that will target the pests and protect the beneficials. The other half keeps offering to spray chemicals but I won't let him. The fact that Neem is also supposed to help with powdery mildew and rust sounds good to me. As well as the fact that it is relatively safe to handle.

Central FL might be a wonderful place for gardening since you can do it year round but the drawback is that pests don't get much population control over winter and pest problems can get out of hand.

Now that the spraying is done for the week, I'm going to go plant some companion pest controls. Onions and garlic!!!!

I live in central FL too, worked at a ranch where owners had $$$ they ordered in dump trucks of "soil" which After 3yrs working there and in my own lawn /garden THE SOIL makes a world of difference. I lived 11 miles away and I'm here to say it's all in the grounds soil! I can't afford trucks of good rich dark soil; but I can get cow poop free which helps smells a couple of days ;! But I can get over that. I hate the dusty sand I have! It's not close to what I had in Ohio and it's where nothing grows easy aside from weeds, that attract the pesky pests. Then the summers heat and water restrictions on top doesn't help. I've learned that mulch gets yucky with white & yellow mold also attracts many ants, so I don't use that, what I found that does help us the black fabric ground cover. Killed off all growth put down some bagged rich soil, milogranite(?) turned it over, in and around with a shovel raked it smooth (didn't bang /pack it down) put down fresh ground cover *get the thickest you can or double it, I as the ranch use the black with the purple stripes, the green stripe is good too but I feel that should be doubled make sure you lay it down taunt ( well it looks so much better laid out tight AND it makes it easier to plant in, too. You can top it with pea gravel or bigger rocks if you want. However, I'd say leave the mulch away just cuz the ants and fungi and cost to replace and to keep the look appealing you have to fluff it up, add to freshen it up. As well as replace it for the mold it gets underneath ;/ . The ground cover held in place by 8" yard staples where ranch not at home spared those either at a min. One staple every 1 sq foot. The ranch has had it this way in some areas for 7 yrs now uncovered too without any weeds rips or showing signs of wear for that matter it looks nice and neat. Then for planting used a razor knife cut "X's" and tucked in and under. Seems to be worker getting better results each year. ✌🏼 Thank care of your ground and it will take care of you! The work gives me pleasure ... Yes I'm a dirt girl 😅

I live in central FL too, worked at a ranch where owners had $$$ they ordered in dump trucks of "soil" which After 3yrs working there and in my own lawn /garden THE SOIL makes a world of difference. I lived 11 miles away and I'm here to say it's all in the grounds soil! I can't afford trucks of good rich dark soil; but I can get cow poop free which helps smells a couple of days ;! But I can get over that. I hate the dusty sand I have! It's not close to what I had in Ohio and it's where nothing grows easy aside from weeds, that attract the pesky pests. Then the summers heat and water restrictions on top doesn't help. I've learned that mulch gets yucky with white & yellow mold also attracts many ants, so I don't use that, what I found that does help us the black fabric ground cover. Killed off all growth put down some bagged rich soil, milogranite(?) turned it over, in and around with a shovel raked it smooth (didn't bang /pack it down) put down fresh ground cover *get the thickest you can or double it, I as the ranch use the black with the purple stripes, the green stripe is good too but I feel that should be doubled make sure you lay it down aunt held by 8" yard staples and for planting I used a razor knife cut "X's" and tucked under. Seems to be worker getting better results each year.