Will switching from hps to led stress my plants?

Hello I'm currently growing with a 400 watt hps dimmed down 50% in a small grow box. Its doing ok I guess but having heat issues if turned up to 100% so decided to purchase an led light suitable for the space. Its a real nice light, cree cxb3590 chips, and only uses 165 total watts! Anyways, the girls have been in flower for only about 2 weeks, will switching the lights stress my plants? Or should I just finish these guys under the hps and scrap it after?

What temps are you hitting now?.. You can change your light it's fine

You're gonna love it... so are your plants. Just prepare for a slight learning curve if this is your first round on LED. Don't be mad and switch back if your normal yield is lower, adjust the recipe and make sure the light is at just the right distance. 6inches or so

Why not keep it at 50% and add the led?

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420monster said:

Why not keep it at 50% and add the led?

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Honestly I don't think I will be even needing the hps. Turns out that the light I got is perfect for my grow box, the box is 18" x30". According to the site the light will produce a ppfd of 1015 for that space! http://www.tastyled.com/product-p/t2-2100.htm

dubekoms said:

Honestly I don't think I will be even needing the hps. Turns out that the light I got is perfect for my grow box, the box is 18" x30". According to the site the light will produce a ppfd of 1015 for that space! http://www.tastyled.com/product-p/t2-2100.htm

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You got the right idea. If a 400w bulb is too hot, 160w of cxb's should help you out! Just gotta dial in the light and nutes again.

Why not just cool down the tent? Could you run a better exhaust system vs changing out lights?

HydroRed said:

Why not just cool down the tent? Could you run a better exhaust system vs changing out lights?

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The hps is in a cooltube withh a 4 inch inline...something like 195 cfm. Damn thing heats up the whole room the tent is in when its at full power and its winter haha can't imagine what its like during the summer ugh I should've done more research and gotten the led to begin with. Oh well it should be here tommorow I'll be selling the hps too a friend anyways

dubekoms said:

The hps is in a cooltube withh a 4 inch inline...something like 195 cfm. Damn thing heats up the whole room the tent is in when its at full power and its winter haha can't imagine what its like during the summer ugh I should've done more research and gotten the led to begin with. Oh well it should be here tommorow I'll be selling the hps too a friend anyways

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Why don't you bring in cold air from outside, or push the heat outside, with the cool air you should be able to run anything as long as you got a decent enough fan to push or pull some air, seems like a major downgrade with LED, I've used led's during flower and there junk compared to what a hps light does, im not saying all the Led's are the same but the one I had sucked for flowering but was good for vegging. I would upgrade the 4inch fan to a 6-8inch you can always turn it down if need be and get a reducer for the size.

What stage is your plant in? Try not to disturb plants in their early flowering, you'll lose yield and maybe create hermaphrodites in the process.
Use a narrow spectrum LED, introducing it for 3 days along with HPS (if you can dim them both), then slowly removing the HPS. But any stress is un warranted in the flowering stage, my man.

You picked yourself a high quality LED. You should see about the same amount of usable plant light as from 200W of HPS (rough estimate, as the HPS is approx. 40% efficiency and the new fixture is @ 50%). The naysayers that diss LEDs are usually thinking about the old-school 'blurple' LEDs that were inefficient and/or underpowered for the areas they claimed to be able to cover. I just had a great first indoor run with a less efficient set of fixtures (based on Vero 29 COBs instead of Cree 3590s) yielding about a gram per watt despite my newbie growing errors such as needing to chuck a couple of ounces due to powdery mildew problems (not enough air circulation and keeping humidity levels too high at night).

Expect to get up to about 4 ounces (or more!) from that fixture (assuming you veg out the plant(s) long enough to properly fill the space).
[In your case the limiting factor is going to be canopy size, not lighting - you have 3.75 sq. ft. ]

Don't worry about spectrum - your Cree COBs emit a plant-friendly broad spectrum.
The only stresses you need to worry about are if if the temps drop too much quickly thanks to the LED, or if your plants experience calcium or magnesium deficiencies due to the use of LEDs. The latter issue won't be a problem unless you are using RO water or tap water that is very low in those minerals. There are 'cal-mag' supplements that you can get for cheap which would address this issue.

If he uses both the HPS at 200W and the 165W of CXB, it would put him at about 146.5W of PAR. (assuming ~32% efficiency for the dimmed HPS and ~50% for the tasty) In his space, that's 39W/sqft of PAR which is extremely high and will likely scorch the canopy. With the tastyLED alone, you'd be at 23.6W/sqft of PAR which is also very high. 23.6W/sqft of PAR is enough to grow 3-4 foot plants.

I'd honestly ditch the 400W HPS unless you plan to use it for a different tent.

Haha I thought yesterday was thursday, so the light will here tommorow not today I have 6 plants in there, only vegged about 3-4 weeks all looking happy and healthy at the moment. When the light comes I'm just gonna replace the hps with it and put it a little high for the first couple days to acclimate them. I don't even really care to much on yeild as this is my first real indoor grow, I'm focussing on keeping them as god damn healthy and happy as can be until harvest. Honestly I would be happy with 1-2 ounces of good bud

ryan1918 said:

Why don't you bring in cold air from outside, or push the heat outside, with the cool air you should be able to run anything as long as you got a decent enough fan to push or pull some air, seems like a major downgrade with LED, I've used led's during flower and there junk compared to what a hps light does, im not saying all the Led's are the same but the one I had sucked for flowering but was good for vegging. I would upgrade the 4inch fan to a 6-8inch you can always turn it down if need be and get a reducer for the size.

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I was thinking about that but summer is coming anyways (gonna be a fucken hot one) and if a 400 watt heats my room up with the windows open now that its winter and 30 f.....I really don't wanna deal with it in the summer even with an ac! As for quality of the led light.....I'd be lying if I said it was amazing which im sure it is because I haven't gotten it yet, but I've done my research and I 100% believe it's a quality , efficient light that's gonna kick the shit out of any other option for my space

dubekoms said:

Haha I thought yesterday was thursday, so the light will here tommorow not today I have 6 plants in there, only vegged about 3-4 weeks all looking happy and healthy at the moment. When the light comes I'm just gonna replace the hps with it and put it a little high for the first couple days to acclimate them. I don't even really care to much on yeild as this is my first real indoor grow, I'm focussing on keeping them as god damn healthy and happy as can be until harvest. Honestly I would be happy with 1-2 ounces of good bud

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Probably more like 6-9oz if the plants are healthy at harvest.

LED or CFL is the way to go when growing in a small area like a grow box or closet....HPS just gets too dang hot in small places......HPS should only be used in larger areas w/ air conditioning and good air circulation ....Yea you will sacrifice some yeild but your plants will be much cooler and happier....plus you will save some money on the electric bill

ryan1918 said:

Why don't you bring in cold air from outside, or push the heat outside, with the cool air you should be able to run anything as long as you got a decent enough fan to push or pull some air, seems like a major downgrade with LED, I've used led's during flower and there junk compared to what a hps light does, im not saying all the Led's are the same but the one I had sucked for flowering but was good for vegging. I would upgrade the 4inch fan to a 6-8inch you can always turn it down if need be and get a reducer for the size.

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dumb uneducated splooging. LEDs come in all shapes and sizes, and quality.

OK now I' m really confused some are saying Led OK for flower. Others swearing no they give no good yields. God now my confidence is shaky for I soon need to flip! Have a 300w going now & Iplan to add another 300w. You guys!

It could be a problem if your LED ain't putting out as strong of light but if she is truly equal shouldn't be a problem just HPS is still superior from every LED I looked into some claim better ones but then why don't commercial growers and breeders use LED?

They ain't trash but I have many doubts sure years from now the technology will be kicking ass if the plasma lights don't kick the shit out of LED. They do really sound promising but again the technology is pretty new but I can imagine plasma taking over in 5-10 years. LED ain't really beating HPS and HPS vertical takes the cake in most efficient grow light hands down.

ryan1918 said:

Why don't you bring in cold air from outside, or push the heat outside, with the cool air you should be able to run anything as long as you got a decent enough fan to push or pull some air, seems like a major downgrade with LED, I've used led's during flower and there junk compared to what a hps light does, im not saying all the Led's are the same but the one I had sucked for flowering but was good for vegging. I would upgrade the 4inch fan to a 6-8inch you can always turn it down if need be and get a reducer for the size.

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I'm with you on that. My led was awesome for veg but flowering took longer and yielded less for me. Like you said though, could have simply been the wrong led 'cause my temps still weren't all that low! Had to upgrade my vent system for all light systems.