Welcome to UK420

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more!

This message will be removed once you have signed in.


GSZZ

Light spaces NOT plants

44 posts in this topic

Sorry to revive a semi-old thread from January but I always had the impression that the plants would stretch to get to the light if it was left at the top of the tent for the plants life....

 

Does anyone know, do you only leave the light at the top of the tent for the whole grow or just at the start of flower.

 

I have 3x 400v 600w dimlux and I kept them 2ft away until they kept stretching in flower and now have ended up with quite a few scorched buds which I'm not too pleased about.....

 

So if i keep these lights at the ceiling the whole grow I will not have plants overly stretching for light? 

Edited by charliepotatoe

Share this post


Link to post


Depends on your ceiling height I guess my friend.  I struggle with stretching plants but its usually down to my bad with the temperature.

Edited by FatBoy77
1 person likes this

Share this post


Link to post

You've only got to watch canna cribs and all the commercial grows in the states, a lot of their lights are always up high and they dont have stretched plants. How high is the sun in the sky? I guess if your lights are bright and strong enough then the plant wont stretch.... PPFD

2 people like this

Share this post


Link to post

This is interesting and I think we’re awaiting an informed explanation.  

There’s a received wisdom, with pretty much any photosynthesising plant, that they’ll stretch and reach for light and we want to limit that in many instances.  Thus, I always had T5s within a few inches of my tops, lots of fan stirring, to dissipate the little heat produced.  Same with bulb LEDs at the moment.

 

T5s aren’t going to put out the heat and light that certain other lamps will (I’m not really au fait with the bigger, brighter, hotter light systems), so it’s harder to mess up.

 

However, it’s intuitive to get the lights as close as possible without scorching.  With tubes, that’s fair enough and manageable.  My current fridge grow relies on a lot of internal reflection and diffusion, which allows a lot of light to reach below the canopy.  Now, the fridge is a tiny space with 5 bulbs totalling 55W, but I can imagine that good lights, higher up in a reflective tent will give a better overall spread of the ambient light than, say, T5s much lower in the same tent.

 

Is the point that, for an equivalent “level” of light at the canopy, a more intense light mounted higher will give much more reflected and diffused light around the rest of the plant?  I can see how that might dissuade the plant from reaching up and, instead, put more effort into the rest of the stem and fattening up.

 

There are some general principles here that I can’t quite figure out and this thread feels like a loose end...

Share this post


Link to post

does this still apply to/with led? 

 

 

 

1 person likes this

Share this post


Link to post

Posted (edited)

@buddy13 I think the whole plant stretching thing is a misnomer. 

 

I've always had my lights firmly fixed at the top of my tent. Ive run t5's 2 foot + above the canopy. Veg plants in the big tent with 2m of head room. I've never seen any excess stretch.

 

Excess stretch comes from low light levels. A plant stretches in low light conditions because of phototropism. When one side of plant is in darkness, auxin cause a growth spurt of the dark side. This is how plants stay directed towards the light. 

When we see low light conditions covering the whole plant the auxin are in overdrive telling the plant to break out of the dark space.

It the same reason a full dense canopy grows faster that an open canopy. Its the shade that drives stretch. 

 

 

 

Put it this way. Id happily run my light on its lowest setting at the top of the tent for vegging and excess stretch wouldn't cross my mind. 

 

Always kinda baffled me people  feeling the need to get light as close as possible. Makes no sense

Edited by blackpoolbouncer
9 people like this

Share this post


Link to post

I’m a growing ‘herbert’ to put it mildly so just me two penneth. Putting my lights up to the top of my tent is something I’ve done perhaps last 12 months. I got pissed off of constantly wondering if they’re too close or too far away (as well as frying some seedlings). My tent is 1.8m it’s not like they’re 92 million miles away. Never noticed any undue stretch really. Infact this is my first grow where running out of height isn’t an issue. I think in part due to knowing what I’ve got to play with from the get go rather than thinking ‘fuck I’ve raised the lights again, when’s it gonna end’. In terms of penetrating light I got rock solid buds everywhere on the last plant I cropped. Hardly any fuzzy shit or trim to speak of. I’ll be leaving my lights up at the top right indefinitely.

3 people like this

Share this post


Link to post
2 hours ago, buddy13 said:

does this still apply to/with led? 

 

 

 

 

Yes, although with big bar LED there's less uneven light when it moves closer due to the very design. Same cant be said for board LEDs

4 people like this

Share this post


Link to post

i'm slowly setting up a new 1.5 tent, had to send for chain and hooks to complete the set up, i run a marshydro ts3000, i'm wondering if i should get another light, thinking neither would be on full power would it be beneficial

Share this post


Link to post

Posted (edited)

Sorry,was a bit early and brain wasn't switched on yet....

Fully agree about the stretching, I've not moved my lights for years...

Was more wondering about the spacing...

Was under the impression that LEDs throw  the light downwards better so less crossover? 

Would this mean having slightly less gaps than with hid lamps, between multi light fixtures?

 

 

Edited by buddy13
Spelling
1 person likes this

Share this post


Link to post

Posted (edited)

A few years now since I heeded the advice from this post. My yields have went up and I grow nicer buds (even the ones furthest away) since I raised the height of my 600w hps. Obviously not too high but I don't heat stress my buds anymore. 

Edited by lennyd79
4 people like this

Share this post


Link to post

Wow, this is the post I've needed to read since I got my decent set up in late January/early February. I've followed the wrong advice for a few months now. I was under the impression that plants had to be a certain distance from the light to get maximum nutrition from them. One site I read advised 12 inches from the plant at 250w, 18 inches for 400w and so on... The light manufacturer also advises this. 

 

I wish I'd asked this question here myself. Thanks to the oracle of this amazing site I shall adjust my set up tomorrow. Which might allow me to crank up the power as the light and most of the heat it generates will be closer to the extraction. 

 

Everyday's a schooldays. 

1 person likes this

Share this post


Link to post

Posted (edited)

6 hours ago, buddy13 said:

as under the impression that LEDs throw  the light downwards better so less crossover? 

Would this mean having slightly less gaps than with hid lamps, between multi light fixtures?

 

Yep :yep: Worth paying attention to whether they have those lenses over the diodes and what degree angle when making choices on LEDs layout. I like the straight down bar lights personally, I imagine for great coverage with panel/board LEDS it'd require alot of low wattage fixtures, but the coverage, output and end result would be spectacular. 

 

e2a I am using a par plus in a single 1m x 1m and its a amazing light, hung straight at the top of the tent. 

Edited by GSZZ
6 people like this

Share this post


Link to post

@GSZZ

 

Hi mate, I just installed a ppfd meter app on my phone (real ones are bloody expensive lol) my question is :

 

Running 2 x CMH (942 & 930) in a 1.2m tent, what ppfd should I be expecting? I've never looked at this before but, never too old to learn so I'm just starting out. 

 

Cheers 

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now