growing inside

[4d3d3d3]

I'm kinda curious as to why you're including Pyrethrin in your watering solution.

Me too. I think the 'why' is fairly obvious, but does it work?

I'll come at this in a different direction...

Bill, are you having mealybug and/or spider mite problems with your plants? If so, the Pyrethrin should knock them down. If not and you plan on growing your plants indoors on a permanent basis, it's highly unlikely that you'll get hit with either type of pest. Such being the case, using Pyrethrin as a preventative doesn't make any sense.

From my understanding pyrethrin is a contact insecticide and isn't taken up by the roots systemically, so a soil drench with it would really only be effective for insects living in the soil. Personally I use an imidacloprid soil drench twice a year as it kills stuff in the soil and is absorbed by the roots to provide protection to the whole plant. It's ineffective against virtually all populations of thrips in our area though due to resistance

[Steve Johnson]

From my understanding pyrethrin is a contact insecticide and isn't taken up by the roots systemically, so a soil drench with it would really only be effective for insects living in the soil. Personally I use an imidacloprid soil drench twice a year as it kills stuff in the soil and is absorbed by the roots to provide protection to the whole plant. It's ineffective against virtually all populations of thrips in our area though due to resistance

Nerts! I've been doing Imidacloprid soils soaks as a preventative every year in spring, and I was hoping that I could rotate it with a non-neonicotinoid systemic so I don't end up with Imidacloprid-resistant mealies. Coming up on 10 years since I starting doing it, and I haven't seen that problem -- at least not yet. If Pyrethrin won't cut it, I'm really hoping that one of our forum members can suggest something effective I can buy for home use in California. As long as Imidacloprid continues to be effective for me, I won't worry about it -- simply a matter of being prepared just in case.

[4d3d3d3]

I know that Bonide recently came out with an acephate-based product for consumer use. Kind of an old-skool systemic insecticide but it's pretty nasty stuff and I wouldn't want to use it on anything indoors. The reason they brought it back is because neo-nic resistance is becoming more and more common. I doubt small-time use like in our case is breeding resistance or contributing in any significant capacity to neo-nic resistant populations. But it's really getting worse. If you search for 'weevil imidacloprid resistance' or 'thrip imidacloprid resistance' there's a lot of recent studies on how prevalent neo-nic resistance has become in the last 5 years.

As long as it continues to work on mealy bugs and scale though I'll keep using it as a preventive. For thrips I use spinosad spray. Very low toxicity and while not a systemic, it does have some trans-laminar ability and gets absorbed in the plant epidermis locally

[billgo2]

A dehumidifier might be a good addition to your setup - actually remove moisture from the air, instead of just moving it around with a fan. Would also provide a source of mineral-free water for your plants.

I plan to have a fan mounted above each grow light, tied into the light timer. I plan to have a dehumidifier tied into the house wiring. Do the fans need to run if the lights are turned off?

[ohugal]

A dehumidifier might be a good addition to your setup - actually remove moisture from the air, instead of just moving it around with a fan. Would also provide a source of mineral-free water for your plants.

I thought you couldn't use that water for anything? At least says so in the manual of my dehumidifier.

[DaveW]

"I thought you couldn't use that water for anything? At least says so in the manual of my dehumidifier."

See:-

https://www.airreviews.co.uk/can-you-us ... er-plants/

However you should not use water from a water softener, that includes the jug type too:-

https://www.gardeningknowhow.com/plant- ... plants.htm

[ohugal]

Thanks!
After reading the article, two things stand out:
1) The author mentions the use of a proper filter, but doesn't specify exactly what type. HEPA-filter or not? I have a standard filter for dust, but fine dust particles still find their way into the water reservoir.
2) He says a well maintained dehumidifier is important. In a few days I'll be giving my unit it's yearly vacuum session. Dust buildup at the coils happens fairly quick.

@billgo2: My apologies for interupting your last question/post.

[billgo2]

I have followed the suggestions. I have a lux meter, local de-humidifier (24 hour), 16" isolating fan (24 hours) and timers for the lights. I started overwinter procedure Nov 1 with very slight water every 4th week and lux reading 10 to 12K. So far, so good.