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Punk#1

Dimmed 315w cmh for seedlings

30 posts in this topic

Was thinking about dimming my 315w cmh to 50% power to start some seedlings, so that's what.. 157w give or take.

 

How far.. Or how close to the seedlings shall I hang the light?

 

Only going to be 9 seedings in 3" pots so not going to take up any more than a square foot of area

 

Ta

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That's a lot of watts for seedlings. You can get by on 30W for the first week or two. Not sure how high to suggest hanging it sorry. 

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I don't dim. 

 

My light starts off about 150cm up and works its way down as the cuttings get stronger. 

 

These cuts were done 5 days ago and have good roots and have been given Canna Start. 

 

As a rough idea, by 2 weeks I expect the cmh to be reasonably close to babies. 

 

large.IMG_20200629_190153_copy_480x640.jpg

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3 minutes ago, Nervous said:

That's a lot of watts for seedlings. You can get by on 30W for the first week or two. Not sure how high to suggest hanging it sorry. 

 

Yeah I know it is a lot, just being lazy really..

can't be bothered going up into the attic to get my 70w mercury vapour, Which seems to do OK for seedlings being about 4000k... it's hanging it and moving lights about and all that faff

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@kaydog might just try that mate do you lower gradually over the 2 weeks yeah?

 

 

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Yep. 

 

If you want, I'll post you each time I drop so you can get a better idea of the rate? No worries either way :)

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5 minutes ago, KayDog said:

Yep. 

 

If you want, I'll post you each time I drop so you can get a better idea of the rate? No worries either way :)

 

That's kind of you mate cheers, you got a diary on the go I could drop in on?

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Posted (edited)

25 minutes ago, Punk#1 said:

 

Yeah I know it is a lot, just being lazy really..

can't be bothered going up into the attic to get my 70w mercury vapour, Which seems to do OK for seedlings being about 4000k... it's hanging it and moving lights about and all that faff

I've got a Lumatek variable cmh but use it vertically with Secret Jardin parabolic. I would set ballast on lowest marker and set it at a height where I feel minimal heat at seedling height. Probably a couple of feet above. If your reflector is horizontal, 3ft might be optimal.

Edited by catweazle1
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Posted (edited)

Just out of curiosity cis I really don't know, how does cmh react to being dimmed? Does it shorten the bulb life any? 

 

Not a diary right now @Punk#1.

 

I will be soon. 

Edited by KayDog

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2 minutes ago, KayDog said:

Just out of curiosity cis I really don't know, how does cmh react to being dimmed? Does it shorten the bulb life any? 

 

Not a diary right now @Punk#1.

 

I will be soon. 

Ive no idea mate I was thinking that myself.. Also with hps if you run the incorrect wattage for the lamp it will give off a different colour temp so was wondering if that applies for cmh too

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Posted (edited)

12 minutes ago, KayDog said:

Just out of curiosity cis I really don't know, how does cmh react to being dimmed? Does it shorten the bulb life any? 

 

Not a diary right now @Punk#1.

 

I will be soon. 

 The colour at the lower settings is very slightly different to the full setting. The full setting is noticeably brighter and bluer. Whether it shortens the life I don't know. The Lumatek is clearly designed with its bulb to be dimmable because the settings are in per cent. The plant grows fine, that's all I can say. This is the way I intend to carry on using it. Will report when the bulb dies. :) Note. A new bulb needs to be run in at full power for a few hours to fuse the bulb chemicals before using the lower settings. Also, a new bulb needs to run for at least 30 minutes from switching on without interruption.

Edited by catweazle1
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Posted (edited)

The bulb should last a year, I'm told. I hope you get a decent life out of it. 

 

E2a - what a shocker.... My cmh bulbs are slightly over 3.5 years old! 

Edited by KayDog
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1 hour ago, KayDog said:

I don't dim. 

 

My light starts off about 150cm up and works its way down as the cuttings get stronger. 

 

These cuts were done 5 days ago and have good roots and have been given Canna Start. 

 

As a rough idea, by 2 weeks I expect the cmh to be reasonably close to babies. 

 

large.IMG_20200629_190153_copy_480x640.jpg

 

 

you back home now then bud?

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@ratdog

No, bro: I'm getting ready for a flying start. I go home this Saturday. I've lost half a year so I've got to catch up. 

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Posted (edited)

51 minutes ago, KayDog said:

@ratdog

No, bro: I'm getting ready for a flying start. I go home this Saturday. I've lost half a year so I've got to catch up. 

 

so this is the grow you are looking after so you can live in a squat ?

 

 

Edited by ratdog

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