Hi

Can anyone give me some advice on how far I shud have my lights from the tops
of plants?

I'm one week into veg, using 250w son-t. It's currently 4ft from the top of the plants
which I think is right but wonder when/if I shud start dropping it a bit closer.

cheers.

As close as u can m8!

Just keep an eye on the temp 28c is about wot u need!

Peace!

Drop it to 18" and see how it goes, if she`s ok you can eventually goto around a ft above the tops with good ventilation.

Mine are never more than 9 inches. I have a computer fan keeping the air moving.

[attachmentid=101166]

3 weeks of vegging.

when people say 28 degrees im assuming that means the temp at the tips of the plants. because the ambient air temp would be much lower,

Yep, although the temp must be read out of direct light. When in direct light it will read much higher.

ok this is interesting as i always went by the probe which was in direct light, basically underneath the globe on top of the plant tips.

ideally where should i place the probe? say for example in between two lights?

i dont think that putting the probe on the wall for example would be correct as that is obviously much cooler than the canopy

ive just pickep up one of those infra red hand held thermometers which you point at shout. where should i read the temp from? thanks guys

wow don't know about the IR temp thingy, but for my readings I simply stick the probe on the soil under the shade of the plants and then guesstimate, but for a while I had a piece of cardbox attached to some string hanging to the same level as the tips, and on the underside of the cardbox was where the temp probe was stuck

worked for me.

so if the temp directly heated by the raditing light was say 40 degrees woudl that be ok if the ambient temp was only 28 degrees?

Yes mate, solong as the plants are the correct distance from the light source, so they are not recieving the radiated heat.

I have my 14 day old plants under 400w HPS and its 2 ft above them. I have a 9 inch oscilliating fan blowing just above the plant tops. It seems to be working ok.

Stick your hand under there for a minute or so, if it burns your hand its too hot for em.

This chart might be of some use..

[attachmentid=101408]

Excellent

I've had mine about 15-16" away for the last couple of days (thanks to the weather, I need the light to keep it warm in there!) and they LOVE it... I don't think I'll be going any closer though, it would require a lot of monitoring - I hate to come home to find them cooked!

Blimey ... I'm really not that keen on 600s any more after seeing that ...

So are they stretching a lot ?

I reckon they're telling you they're ready to flower.

I don't go for this "wait for alternate phyllotaxy" lark myself.

4 weeks seems optimum for me.



oops - just read your other post. That light needs to be 9 inches from the light, trust me..

Or is the light covering a wide area ?

Hi,
Why not

So you keep saying but if you are flowering seedlings after 4 weeks you are never and i mean never getting the best out of em cos they have never become mature.Potency and yield is affected not to mention vigour

So i disagree and say to anyone,let your seedlings get to maturity before flowering or taking clones

If height is an issue from a seedling,wait a while to take cuts and start from there or when the seedling does become mature you can always chop it back at worst

Owd

Wow, your right - at 18" the 400watters do better than the 600's at 24"!



Really? I still have a lot of upward room left - I was going to wait another couple of weeks or at least wait till I see the sex naturally without using 12/12. How much further do you think they will grow up given they are 90% sativa?

EDIT - Owberb, just saw your reply... I take it you think it's worth the wait then I don't want to rush anything, I really want to treat myself to something a bit special if I can

Might as well flower the first crop though

Hopefully I'll have some cuttings later to try ... and I'm evaluating the cured product while getting another grow in.

My clones are going to be from revegged mums so ought to be pretty mature ?

sorry theory I misread your other thread to mean you were at week 6.

If you have the headroom longer is better up to a point.

Awesome cheers for that, I was excited and isaapointed all at the same time