Quote Originally Posted by SyDsHo
I just remembered your "spraying only the lower nodes as to not scorch the top? What do u mean by this? Because it is cooler lower? And what are u spraying? I only spray my girls with Neem. Are you talking pest control spray also? Thanks. Again.
Someone else will have to answer the neem oil question. Have never had pest issues, but wouldn't apply neem with lights on. Worst bugs I get here are the wasps, and the neighbors flies. (all of my neighbors have got horses)
Looking back at the post, I noticed I didn't mention that I veg indoors and flower outdoors. Fewer hours of heat in the shed helps. A few years ago I tried vegging outside too, and took me 4 months of frustration and failures to finally talk my wife (Amber) into at least starting the plants indoors.

Every little drop of water acts like a magnifying glass, and can burn, especially using HID's...plus there's the added worries about high humidity and heat causing mold.
The combination of desert heat, and using 400w HPS's, I avoid misting the tops with water and foliar applications, unless I raise the lights (or just swivel the lights out of the way, see picture below) till the water has been absorbed or evaporated. (10 minutes or so)

When I need to foliar, I go in about 15 minutes before lights-out, turn out all but 1 light, do the foliar thing, then as I'm leaving the room I turn out the last light. Turning lights off a couple of minutes early has never caused me problems.

I usually have no problems at all with lower humidity levels in flower, and strive to keep the levels lower. Also, I vent the room, even with the a/c on. But evaporation just from watering gives a little bump to the humidity anyways.
Flushing the pots is staggered over a couple of days, and is done first thing in the morning. If I flush 'em all at once, humidity skyrockets, like Houston during a heat wave.

Lastly, I use a sheet of 3/8" plexiglass under the lights as an added barrier to help keep the direct heat off the plants. (wiped clean of dust, daily)

(* pix below...The 2 x 4's are screwed-in to the 2 x 4 on the back wall (tall white) with only 1 screw, but they rest on top of the other 2 x 4 allowing me to swivel the lights to any position I need) Perhaps I can get a better pix later today, if anyone is interested.

HTH...Rusty