Using arm to test how close to plants can safely get

i’m pretty sure i read this in one of these threads but can’t find it now. I have new light coming in and i was going to try and find how far away from plants i needed to keep them to be safe by putting arm under light at different heights. anyone got a method for doing this?

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If your hand/arm feels heat from the light then your plant will too

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yep, i got that part, but if you just go under light for 5 seconds u might not feel it but if under 30 seconds u might. was wondering how long to not feel heat. was going to keep getting closer to light until found when could start to feel heat.

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@monkman I use the backside of my arm or hand to hold underneath the light. If it’s too hot for my arm then it’s to hot for my plants! It’ll literally feel like a skin burn so be careful! I actually got way too close one time and burnt my hand really bad. OUCH!

There are tool to measure the light distance too. The only time I’ve used one is for demonstration at work. If you pay attention to your plants growth they will actually tell you if they’re happy, lol. Too close and they get burnt by the light. Too far and they will grow really slowly. The sweet spot is anywhere from 12-24 inches depending on the light and stage of life. LEDs don’t have a lot of heat and most people think it’s ok to get them really close. They don’t take into consideration how INTENSE the LEDs have become. I’ll post some pics of my new LED this afternoon to give you a better idea. Hope that helps!

Happy Growing!
GrowMarijuana.live

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You are going to use a cmh light if I remember correctly, you want your lights at least 18" or more

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If your at that point where your just not sure exactly where to put it, them hang it where you think it needs to be, monitor it for two days, if the plant still looks happy, then drop the light 2" and repeat the process

The plant can tell you more about where it wants the light than your arm ever will, you just have to monitor it and see how she responds

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yep, that’s it @HornHead will be using 315 for this and thanks don’t have to put arm under, i also would have probably given myself sunburn lol

ty @TDubWilly i will use that procedure when i get it installed later today, i hope lol. i was planning on starting at 3 or 4 feet as they are just coming out of germ. got second set of leaves showing yesterday, but i had to get change of light because i have to run in dome until i get tent in in a month. would not be able to use the 5 led a21’s i was using as wouldn’t be able to get them close enough with new dome. the dome i have now only has a half inch clearance of two of the plants.

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LED’s during veg keep around 18 to 24 inches . Then during flowering put the light closer like 10 to 12 inches from light keep the humidity around 55% to 65% seems to make [he buds bigger more dense and if you keep a bag of (co 2 )365 co 2 you can find it on Amazon the bags are lots easier to use then the co 2 tanks … co 2 the 365 is activated and ready to just hang in your tent 1 per 25 square foot . Not cubic feet just do the math on a 10x10 you have 100 square feet so 4 bags of co 2 365 plus … one co2 takes one month to get activated and it’s also a 365 … They last around 8 months for $34.99 you can’t go wrong 1 plant will produce at least another ¼ lb. With the co2 denser buds … I’m old school so I call them buds instead of flower it’s legal in Okla now I can grow 12 plants legally that’s my 6 and wife’s 6 . It’s great to finally be legal to drive away from dispensary and have 3 ounces on my person (or 6 oz’s me and wife ) Okla Grower JJ

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Ok seeds started on November 9 this is where they are at currently They look healthy but does the distance from plant to canopy differ with say y’all leds and my cfl? If so what’s recommended for cfl distance from canopy, always grow outdoors but adopted two inside plants from friend. Weather doesn’t permit outside right now thanks a million y’all.

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don’t know which cfl you are using but i have a sunsystems 315 for veg and 630 for flower. i keep them 15 to 18 inches above plants but not when they are little. when in seedling stage i keep light at tallest it can be and then start lowering it after going into veg stage.