Backyard Aquaponics
A place to discuss aquaponics

I was reading that calcium hydroxide, which some of us already add to our system water to buffer the pH up, is a decent insecticide by it's own right when sprayed onto the offending insects.

I've had some aphid problems on my capsicums and could not find much to use against them that was fish-safe. However if I were to spray calcium hydroxide foliarly, it seems like that would have no negative effect on my AP system water, correct?

Hydrated Lime
Hydrated lime is also called calcium hydroxide. This simple substance has been mixed with water and sprayed over plants as a basic pesticide for many years. It is known to repel aphids, flea beetles, Colorado potato beetles, squash bugs, cucumber bugs and other undesirable insects. Hydrated lime is distributed with the use of a garden hose and garden sprayer and can be applied to dormant plants prior to the growing season. If applied directly to foliage or to roots, it may burn and destroy them due to its corrosive base properties.

Hydrated lime can also be used as a deodorant for organic wastes and carrion.

http://www.epa.gov/pesticides/reregistr ... es_red.pdf
http://www.ctahr.hawaii.edu/coqui/docum ... label5.pdf
http://naldc.nal.usda.gov/download/IND43894203/PDF

Aye, the question is, is a dilution that is safe for plants going to be effective against insects?

Hydrated lime is also called calcium hydroxide. This simple substance has been mixed with water and sprayed over plants as a basic pesticide for many years. It is known to repel aphids, flea beetles, Colorado potato beetles, squash bugs, cucumber bugs and other undesirable insects. Hydrated lime is distributed with the use of a garden hose and garden sprayer and can be applied to dormant plants prior to the growing season. If applied directly to foliage or to roots, it may burn and destroy them due to its corrosive base properties.

Never tried it,but first thoughts would be it wouldn't work,the stuff is a bugger to dilute,so the particles you would be spraying would be quite large and i think it will coat the leaves as it dries causing problems for the plant.Secondly as a very strong base i wonder what effect the very low PH would be on the plant leaves and the plant itself,i could see that being a benefit against fungus but at what effect to the plant itself,maybe worth a try on a sacrificial plant to monitor the effect and effectiveness
Wood Vinegar gets my vote in the fight against bugs..

+1 on everything Dasboot said and a double plus on the Wood Vinegar.

Yea, very low solubility, so you wouldnt need much- just use the fines.



It's a strong base or alkali, which has a high pH, and I think it would damage leaves on some plants.

Ok, calcium hydroxide looks like a no-go.

I've never seen/heard of "wood vinegar", it's not a product anyone in the US uses I think.

My biological controls for insects seem to be working though, I noticed there were 3 adult aphids trapped in the sticky droplets of my sundew plant that I placed in one of the grow beds

Here's some reference to where it might be available in the US.
http://backyardaquaponics.com/forum/vie ... &start=630

It's a great natural product and works instantly but again it needs to be used carefully.