Mix BT w/ Potassium Bicarbonate?

Does anyone mix Potassium Bicarbonate with their BT (spinosad) spray? Is it effective? Any negative side effects?

Thanks in advanced.

I've been considering doing that. Although BT and Spinosad are very different, I think you are asking about mixing the beneficial bacteria with Potassium Bicarb. I haven't done it, but I don't see why not.

Mixing a pesticide like Spinosad may affect the bacteria, although I have used SoluNeem mixed with BT because the SoluNeem label says it's OK. If you have pests, then use a pesticide.

So I'm anxious to hear from others about it. I spray for both worms and fungus, so mixing them would make me happy.

The only time I mix together is if its BT + a bacterial antifungal. I don't mix something like potassium bicarb because of the chance of killing the BT.

I suppose you could do a test to see if the BT dies when mixed with something else. Next time you find a caterpillar, bring it inside into a container with a leaf and spray with mixed bicarb + bt.

Yes, sorry I meant Monteray BT or Spinosad. I'm spraying for worms and fungus right now too and I'd like to get 2-in-1.

I don’t do that. The ph is important for potassium bicarbonate to work. It works very well. I’m not sure BT won’t be affected by the other. Spray opposite days. They both are very effective. I’m using both. i have used both, same days, different sprayers when PM appears. I spot treat with potassium bicarbonate. It keeps, easy to have handy. BT mix use throw away. I think there’s a 24 hour window to use it. Good luck with your harvest.

Not sure what the living BT spores would do, but Spinosad is a byproduct of bacteria, not living bacteria.
Monterey spinosad adds way too much ppm with the carrier solution and bicarb, Conserve SC may work, much higher concentration of spinosad.


I tank mix the bt/spinosad with each other and Regalia, it just seems too complicated with a reactive chemical like potassium bicarbonate to mix anything

This “spinosad soap” is labeled for powdery mildew and other pests.

Never used it, so can’t comment. It just popped up in search.

High pH renders BT ineffective

Potassium bicarbonate is useful against PM because it's alkaline, and molds thrive in acidic conditions

BT is a bacteria which sporifies and produces a toxin when it's exposed to the alkaline lower gut of lepidopterus insects