superfruit Posted January 21, 2021 Share Posted January 21, 2021 @growinggold thanks mate. Are you using LED? 1 Link to comment Share on other sites More sharing options...
growinggold Posted January 21, 2021 Share Posted January 21, 2021 Yeah I'm running 150w scope v2 led and 220w highlight led in a 80x80cm Link to comment Share on other sites More sharing options...
superfruit Posted January 21, 2021 Share Posted January 21, 2021 (edited) Should be fairly easy for you to manage VPD then as your leaf temps will be sensible. Due to using HPS I think my leaf temp will probably be significantly higher than the room temp and will throw those charts out the window. If you try changing the chart to +5c leaf temp then there leaves no green zones. Something feels off here. If i'm understanding this correctly I probably want to be targeting an ambient temperature of around 23c where possible, to help keep leaf temperature down a little while under the HPS. Into the rabbit hole I go: dammit @NezA why did you have to tempt me into this fancy tech haha Edited January 21, 2021 by superfruit Link to comment Share on other sites More sharing options...
growinggold Posted January 21, 2021 Share Posted January 21, 2021 I think you maybe be being a bit hasty with your temps. I get that hps is hotter but surly Its +2 rather then -2 give the 4c difference. +5 seems an awful lot. Link to comment Share on other sites More sharing options...
superfruit Posted January 21, 2021 Share Posted January 21, 2021 (edited) At the moment @growinggold I'm only going by what these websites state - a +10f difference, which is 5c I think. I guess here's why it's important to have good airflow around them. Edited January 21, 2021 by superfruit 1 Link to comment Share on other sites More sharing options...
growinggold Posted January 21, 2021 Share Posted January 21, 2021 We need uk420 infrared thermometer. Someone must be able to give us a steer here.. 1 Link to comment Share on other sites More sharing options...
superfruit Posted January 21, 2021 Share Posted January 21, 2021 (edited) Another nice quote from the BlackDogLED website: Quote High Pressure Sodium (HPS) in particular converts a significant portion of the energy consumed by the light directly to non-visible infrared light in the 810-830nm range, peaking about 819nm. This infrared light is perceptible to you (and plants) by the warmth it creates when exposed to the light. Additionally, much of the visible light HPS bulbs produce is yellow and not highly-utilized by plants. This radiation not used for photosynthesis or other chemical reactions only serves to heat up the leaves, requiring cooler ambient temperatures to keep the plants' leaves at their ideal temperature. Edited January 21, 2021 by superfruit Link to comment Share on other sites More sharing options...
growinggold Posted January 21, 2021 Share Posted January 21, 2021 So about 4c difference 1 Link to comment Share on other sites More sharing options...
superfruit Posted January 21, 2021 Share Posted January 21, 2021 1 minute ago, growinggold said: So about 4c difference And if you pop +4c leaf temp into one of those Pulse charts a really ambient low temp of 22c requires 80% humidity for a VPD of 1.2. just feels wrong for some reason - 80% humidity will case a Carboair to lose efficiency, among other issues. Google isn't making life much easier Link to comment Share on other sites More sharing options...
growinggold Posted January 21, 2021 Share Posted January 21, 2021 Imo you want to put plus +2 in not +4. As the difference is from -2 not 0. ? Link to comment Share on other sites More sharing options...
mikeydoughnut Posted January 21, 2021 Share Posted January 21, 2021 (edited) @NezA sounds like your journey is planned out. Wish i could be so organised. Good luck with the living soil n that. I like how its pretty much how nature intended but theres no way im having worms in my house! @superfruit this is what i learned, again, practically the other day. Cannabis can can consume ridiculous amounts of light energy. I believe its the far red spectrums in HPS that will generate the heat (uv). Have you got a fan speed controller? Try and use that to negate the heat generated by the hps. A cannabis plant can efficiently use upto 2000ppfd. This is assuming you are feeding enough and watering is bob on. You want to use as much light as possible whist controlling temps. So a combination of extraction and oscillation of air over the leaf surface could bring your temps and humidity down in one swing of the bat. The crucial thing here is leaf surface temp. I hear its around 1/2 degrees below ambient air temp, i could be wrong. Depending on you stage of growth it might not take much tweaking. If you're about to go into or in flower get those numbers down as best you can. I was watching a video on youtube and a lady said she understands the frigtening thought on budrot but if you follow the vpd and its in balance you should be good .... obviously 70/80% humidity isnt good but a bit above or below ideal isnt the end of the world. Apologies if i mistook what you were discussing, my heads fried from home schooling. Edited January 21, 2021 by mikeydoughnut Link to comment Share on other sites More sharing options...
superfruit Posted January 21, 2021 Share Posted January 21, 2021 37 minutes ago, mikeydoughnut said: The crucial thing here is leaf surface temp. I hear its around 1/2 degrees below ambient air temp, i could be wrong No trouble man i know the pressures of home schooling - quite the world we are living in! I think previous discussions have been based on LEDs which give off much less heat, whereas my issue is the HPS bumps leaf temps up by around +4C 1 Link to comment Share on other sites More sharing options...
superfruit Posted January 21, 2021 Share Posted January 21, 2021 On the plus side, I've just connected up the Inkbirds and sure enough I can see them working to meet the preliminary rules I've created. Impressive gear! Using an Android emulator I also get the data streamed to my PC too 3 Link to comment Share on other sites More sharing options...
mikeydoughnut Posted January 21, 2021 Share Posted January 21, 2021 5 minutes ago, superfruit said: No trouble man i know the pressures of home schooling - quite the world we are living in! I think previous discussions have been based on LEDs which give off much less heat, whereas my issue is the HPS bumps leaf temps up by around +4C But 4 degree could be negated fairly easily if your water, nutes and root temps are all in check and you get to keep all the light energy you're providing. Just bring cooler air in quicker. Cools shit down, gets shut of some humidity and creates really nice airflow between the plants. My sms is @35% and the ladies are in their dancing. The easiest option would be to reduce light intensity but then you'd sacrifice yield. I know where youre coming from though i had a 400w hps and i was literally losing my mind in summer time with temps. Try dial it in before we get to june/july/august. Yeah this teacher lark is pissing me off to be fair. Its made me realise that my youngest lads teacher is fucking useless. Hes gone backwards since. Ive ordered some textbooks off the internet. Im going to try get him past where he should be. Thing is without all this i wouldnt know until parents evening and she'd blame him. Hes a good lad. Hes too scared to be naugty or misbehave because be knows theres a time and a place. Theres things he should know that he genuinely doesnt. Its not on. 3 Link to comment Share on other sites More sharing options...
superfruit Posted January 21, 2021 Share Posted January 21, 2021 @mikeydoughnut stick in there with the schooling, sounds like they're benefitting! I'm only in the very early seedling stage (just showing the cotyledon today. The 250w hps hung high is creating an ambient temp of 22c with the 4" rvk at 50% speed. The RootIt is keeping roots at 24c, and the Inkbirds keeping temp at 24c & rh at 63%. Clever these gadgets! 4 Link to comment Share on other sites More sharing options...
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