Lighting & leaves

[The Devil]

My little 30cm tall plants have been going beautifuly with the old MH light set at 1300mm away, the leaves pointed up in the air & leaf internodes were 25mm between.(very healthy looking)!

 

Since changing the old globe to a new one & adding the 600w cooltube in the closet,(i havent played with the digital HPS yet) i followed the light height placement guide on Cannaversity. I moved the lights down to the roughly optimum recomended 45cm away from top of plant. The room temperature & humidity levels are exactly the same as when everything was running smoothly, but now my leaf internodes are 5mm & the leaves are green looking, but facing downwards & they are turning or folding in on themselves like they are closing up. is this normal? i have done research on my problem, but the only information that seems to apply to me is that the lights are too close?? although Cannaversity is stating that they are at a good height for the wattage.. I have moved them up to 65cm away to be on the safe side. So should i keep following Cannaversities information, & i have nothing to worry about? or am i doing the right thing & moving the lights up? as they were going really well beforehand.

Cheers,

[Dallas]

Gday mate..

 

The best way ive found is to put your hand on top of the plants and if your hand feels to hot, well then its to hot for the plant

 

Raise light until its feels at a good temperature. But you have to check the hight of the light and correct when needed every week depending on growth rate..

 

Or it might be The Claw..

 

Dallas..

Edited July 4, 2010 by Dallas

[jimbojones5678]

It definitely sounds like you have the bulb too close - as Dallas said the hand method is fool proof.

 

Jimbo

[The Devil]

Thanks guys, it definately dosn't feel hot even holding the cooltube "which has me baffled".. and at even 20cm from my hand it actually feels slightly warm,not hot at all. so could the new light globes be producing too much light? if i leave the lights at 1mtr away, is this the safest way? from what iv'e researched & then applied, i should be on the money, but i'm not...

[Free Wheelin Franklin]

hey the Devil how are ya mate?

I have found in the past that sometimes if you lower the lights even to the right height too quickly you can burn them a bit, better lowering gradualy over a few days.

 

FWF

[Dallas]

If u can mate, take a few pics that would help us to determin whats going on

 

Dallas..

[Mercury1600]

Does the kelvin rating of a bulb affect the plants growth much?

for example would a plant under 6700k (closest to natural) grow better then something under 4700k (yellow) or 10000k (very white, turning blue) ?

 

merc

[Free Wheelin Franklin]

Too much light intensity too soon! Edited July 7, 2010 by Free Wheelin Franklin

[Radic]

greetnz

leaf curl is often a direct result of shock

and can happen in 1hr

imho

always make changes gradually

eg lower the lights over a period of a day or two

by about 1/3 of the distance from the plants till the correct hight is maintained

flush asap

spray with Kelp for shock

air circulation is crucial do you have a osculation floor fan???????

low grow room temps are a must to maintain

irey guidance

[The Devil]

Thanks guys! makes loads of sense FWF, i will try moving them gradually down over the next few weeks. i am guessing that if it was working well before i shouldn't actually fool around with things too much though.. Yes Radic i do have a fan blowing (one of those new fandagled Dyson bladeless ones) for 18hrs a day just moving the leaves around slightly & the lights are on for 24/7. Thanks for the kelp suggestion as well! Alls good now since i raised them to 1300mm from top of plants, & in three days they are doing fine again