Led vs HPS growing

PJ Diaz

Well-Known Member
I read a lot of post which say this, and it makes me question if people are doing the right thing using the light to heat their environments and not floor heating to warm up the roots.

What are your temps in the winter season and what changes do you make from summer to deal with it?
VPD is determined by leaf temp, not root temp. Using a heater seems like a waste of energy to heat up the leaf temp. I figure it's better to use some HID type lighting to get the infrared heat blasting directly on the leafs, and you also get the nice side effect of photons. In winter, I will struggle to get temps above 70 with LED lighting only and no supplemental heat. Part of the issue is that I have to run lights at night when it's cooler, because the cost of running them during the day is like 4X vs at night.
 

DukeFluke

Well-Known Member
Easy solution is don't put your pots directly on the floor. Use raisers.
True. Underfloor heating is also a solid investment if it's viable. Cheap as well. Can transform a winter grow and comes into it's own if you can't get the root temps to stay at or above 19c without burning Kw of leccy.

VPD is determined by leaf temp, not root temp. Using a heater seems like a waste of energy to heat up the leaf temp. I figure it's better to use some HID type lighting to get the infrared heat blasting directly on the leafs, and you also get the nice side effect of photons. In winter, I will struggle to get temps above 70 with LED lighting only and no supplemental heat. Part of the issue is that I have to run lights at night when it's cooler, because the cost of running them during the day is like 4X vs at night.
I can only speak from my experience, but lowering my extraction and turning on the underfloor heating has got my plants loving life, even with ambient temps not far above yours.
I think warming the root system speeds up their metabolism and mitigates a lot of the problems of cooler starting air temp.
 

Kassiopeija

Well-Known Member
Part of the issue is that I have to run lights at night when it's cooler, because the cost of running them during the day is like 4X vs at night.
still better this way as otherwise most growth would've to occur during an even colder night... enzymatic activity would limit tremendously then...
 

Kassiopeija

Well-Known Member
I guess that depends on what our opinions are of blowing the other away. IMHO, the right LEDs have shown in case studies to increase thc and yield not a ton, but i thought it was impressive. Then you add in operating costs, cooling, and bulb replacement. Are all factors i consider and LEDs are far better. Granted, Im talking about high-end LEDs like California lightworks, Electric Sky, HLG etc. Not these cheaper one's
Well, the argument goes both ways, some need to heat up their place in winter under LED. PS & enzymes is actually stronger under heat, if you sup CO2, its necessary...

Then, generic white CRI LED or blurple lacks UV, which is energy-costly to create but one major factor to increase THC. They DO give off more PAR, granted :hump:, but you mustn't get fooled by some of their marketing gags:

COBs are very respectable lights. Crees are classics. California lightworks has a newer more efficient led thats about 40% more efficient than anything else on the market. Their 400watt LEDs pull 400 watts at the wall and American made. Their 400 out grows a 1000 watt mh light and a lot cheaper.
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Kassiopeija

Well-Known Member
Hey buddy I was replying to someone who said LED has more evolving to do to catch up.
yes, that's been me... with maurice liking my post outlaying some of the weaknesses of LEDs, which you did snipe at. Perhaps a misunderstanding on my part... :eyesmoke: hope you didnt took too much offense.:peace:

LED is great, esp. lots of diodes driven undercurrent, can be kept close... have you amended with 280 or 310nm? Damn expensive, degradation, cannot be kept close, and IF, increased UVB diode count would kill your upfront cost calculation. Some wavelengths are missing... monochromatic excessive light is not optimal for leaves...

Some of the height problems of HIDs can be overcome by vertical, or smart plant training, or...

Long story short, optimally is perhaps a combination of different designs, but individual situations are different, so are calculations.
 

DaFreak

Well-Known Member
I personally have not noticed a big change between HPS and LED. Obviously CMH is better than HPS. But I had always heard slow growth for years and that's one of the reasons I held out so long, but honestly I don't see it. Messed up my first grow with them and trained less thinking they weren't going to get that big and I ran out of space. I'm comparing 1000 hortilux bulb and 600 COB. And I saw people get good results with blurples but sorry, that color would have taken any love for these plants I have left.
 

Kushash

Well-Known Member
When dialing in a grow after someone makes the switch to LED, do they find the need to increase or decrease the nutrient solution E/C in a DWC or drain to waste grow?
 

Rocket Soul

Well-Known Member
When dialing in a grow after someone makes the switch to LED, do they find the need to increase or decrease the nutrient solution E/C in a DWC or drain to waste grow?
Id say the tendency is yes, a bit more ec for higher intensities (who changes their light for something weaker?) but it really depends on where your starting.
 

Kushash

Well-Known Member
Id say the tendency is yes, a bit more ec for higher intensities (who changes their light for something weaker?) but it really depends on where your starting.
I would compare the two types of lighting with the LED being more intense, not weaker, working the plant harder.
Transpiration would increase in this situation. I would wonder if E/C should be lowered not raised with the increase in transpiration even if the plants growth increases.
That's why I use hydro as an example not soil. So many variables in soil would make it harder to judge vs hydro IMO.
 

Kassiopeija

Well-Known Member
That's why I use hydro as an example not soil. So many variables in soil would make it harder to judge vs hydro IMO.
Well, you got your frequency of fertigation in hydro which affects some of the nutrition uptake, in soil one can just stretch sharp soil down a bit with either perlite or lightmix or else... then begin feeds once the first def symptoms start showing in places that get lollipoped away, anyway
 
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