Switching from hps to led

[Guest]

12 hours ago, ratdog said:

i think it would be useful for those succeeding with all led to give us the ambient temps of the rooms they grow in without heating

My south facing room is 20c with the window open and no heating on.  I need a 180w tube heater in there for lights off. 

My North facing room is 18c with the window shut.  I need a 240c tube heater in there for lights off. 

Lights on for both sits around 25-28, if it's in that range I leave shit alone. 

[KC]

When we're talking temps where are people talking about? Canopy or floor? I measure at the floor with a govee and a cheap thermometer sits on the top of the carbon filter. There's a difference as you can imagine.

[Guest]

Just now, KC said:

When we're talking temps where are people talking about?

I always monitor canopy, very little interest in the rest. 

[blackpoolbouncer]

13 hours ago, ratdog said:

i think it would be useful for those succeeding with all led to give us the ambient temps of the rooms they grow in without heating

 

i would find it very interesting considering some comments recently

Well, to throw a cat amongst pigeons. Growing in the house with ambient temps never going above 23'c pot level I did 1400g on 720w of LED with issues. The lung room was set at 20. 

 

Anyone that thinks hps is a superior light is definitely a dinosaur. 

 

Cant comment on my shed grow as that's obviously heated and I'm keeping roots and ambient between 25-28 to see if it actually makes a difference.

[NezA]

Just now, blackpoolbouncer said:

ambient temps never going above 23'c pot level

 

Any idea on what RH you were running at those temps?

[Guest]

@blackpoolbouncer aye, 2gpw is definitely the new benchmark.  Hitting it on the regular now. 

[blackpoolbouncer]

Just now, NezA said:

 

Any idea on what RH you were running at those temps?

Low for the most part given time of year 45 average at a guess. 

 

I'll be honest mate. I've not had a hygrometer in my tent for over a year. Other than day 1 in the new shed I just have a thermometer on the wall in the lung room which tell me everything i need to know. 

I feel all fancy now ive got a probe in the soil for the inkbird tbh. 

 

As long as my lung room is warm when I walk in I know everything's all good without without checking my one thermometer. If I sweat my tits off were getting close to 30 and if its not still warm in  t-shirt it's getting too low. Don't even bother with a thermostatic plug or controlelrs for the heaters. Just flick a swith if it's gonna be frosty to turn it up to max and flick it off to nothing if its a really hot day and that's all the control I need.

 

I guess that comes with experience though. 

 

@fatboy77 certainly is mate. 2gpw is quite easily achievable imo and tbh with the right cutting monocropped I dread to think of the possibilities. 

I've got cuts that I'm sure would do not be that far of hitting 3gpw. 

Mental

[NezA]

Bob on what I'd expect for those temps @blackpoolbouncer thanks for confirming.

 

I'm itching to get set back up now! If I can hit anywhere near 2gpw that'd be awesome. Can't wait to put all these thoughts into practice. It's driving me nuts sitting on my thumbs.

[4kali]

talk about how ive been stuck in my old ways, i must be the t rex of all  dinosaurs, reading this thread makes me realiase just how much ive got to go with the times, or be left behind so to speak

I really like the idea of a lung room though its something ive pondered on for a while now.

which leds would you guys go far with low head height, one that you can get really close to the plants without having negative effects

 

[Should Know Betterer]

Do leds give less urgent need for air exchange? I always thought with hps you've got to aim for around 3 changes a minute, with leds is it OK to turn down the extraction to maybe 1.5 to 2 air exchanges a minute? 

[NezA]

@Should Know Betterer with HPS your extraction is primarily for removing the heat from your grow room. A HPS in a 1m2 tent would need a 6" fan to bury the heat. The air exchange provided is way way more than adequate to keep the air fresh you can do the calculations yourself. 

 

LEDs require the exact same air exchange to vent O2 and intake Co2 but HPS requires more extraction than that because they're more efficient at heating a space than an LED. If you ran a HPS at the minimum level to maintain Co2 you'd cook your plants.

 

E2A: I suspect that even an LED will require more than the bare minimum extraction but just much much less than we're used to with HPS

Edited April 12, 2022 by NezA

[blackpoolbouncer]

Of anything they woukd theoretically require more exchanges per hour because the plants are "breathing" harder.

 

In reality if its a toss up between cold and turning the extraction down a bit I'd go with the lesser of the twoneveiks with extraction. As long as humidity isn't an issue it would be fine I'd say.

 

E2a. @NezA above does make good points 

Edited April 12, 2022 by blackpoolbouncer

[NezA]

Agreed, we already know that in order to run some LEDs flat out requires more Co2 than is present in the atmosphere naturally. Think of it like climbing Everest without oxygen, we're working the plants hard but not giving them enough air to breathe. Obviously there's a hard limit to the Co2 available in the atmosphere though, so at a certain point it doesn't matter how good your air exchange is you've hit that limit. 

 

I'm fortunate to be in a loft where I can intake directly from the bedrooms below (thanks to some defunct warm air heating ducting) which will have a way higher Co2 density than occurs naturally in the atmosphere. My hope is that I will potentially be able to push my plants a bit harder than most because of all the additional Co2 the people below are expelling in their sleep.

[Linch]

@Should Know Betterer you got that the wrong way round mate. Its 1 air exchange every 3 mins I believe. 

[Guest anarchycamp]

Has no one tried ceramic heat bulbs to keep the temp constant lights on/off?

Going to look into Leds this year I reckon, shame I've got a beast of a wrong driver