seedling / MH use

[darkhollo]

When can you put seedlings under a MH?

I have a 600w MH that I'd like to use for veg. Currently the are under 4 CFLs and I was wondering when/how to transition them to the MH.

How close should it be? (It's an air cooled hood.)
Do i have to ease them into the higher intensity?

TIA
-dh

 

[Raistlin Majere]

i veg from day one under 600w MH (conversion bulb)
however i have CFLs now to start them under next time
i always keep mine within one foot with my aircooled hoods
hold your hand under them backside towards the light
if its to warm for the plants you can tell

i don't know if they must be eased into the HID lighting or not i have never done that
but mebbe, if it was me i would keep the light a bit high and lower it slowly
but get advise from someone who has done it, i am just rambling now

welcome to ICM

 

[Buzz Lightyear]

Get your chloroplasts stacked up not spread out

Get your chloroplasts stacked up not spread out

When I move my seedlings from indoors to outdoors, I give them only 1/2 day of morning sun for a week then full sun. You have to harden them off. The plants receptors to catch light are geared toward maximum absorbtion using florescent lights and want need this as much with the hid.

Thomas Watson explains...

To make the most of the light you've given them, the plants have grown leaves that are a bit wider and thinner than those of outdoor plants of the same type. Inside the leaves the chloroplasts, those little bundles of chlorophyll (that stuff that makes the plants green), are arranged in thin, even layers throughout the leaves, to better capture and use every bit of light striking those leaves. In other words the leaves are adapted to be excellent solar collectors.

Take that plant directly out into bright sunlight, and the intensity of light is overwhelming. Plants grown in direct sunlight respond - as they grow - to this very different environment by producing slightly smaller leaves and by arranging the chloroplasts inside the cells of the leaves so that they are not as exposed to broadside blasts of sunlight; they sort of stack up, instead of spreading out. A seedling grown indoors has not made such an adjustment; the leaves are over-exposed and sometimes, quite literally, burn out.

And so, when the time for transplanting seedlings approaches, this is what you are most likely to have under the seed starting lights: healthy, lush, green little plants with wide leaves, a thin cuticle, long cells with thin walls, and chloroplasts arranged to grab as much of that gentle fluorescent light as they can. Seedlings perfectly adapted to life indoors and under lights, but very poorly suited to the real world of your garden.

Existing leaves cannot grow smaller, but the cells of which they are made can rearrange their chloroplasts well enough - given time - to prevent serious damage while the plant is busy putting out leaves better adapted to life in the sunshine. (After the plants have established themselves in the garden take a close look. Compare the old leaves with newer mature leaves. You can often see the difference.) A plant can thicken its cuticle by depositing waxes on the outer surfaces of its epidermal cells, and can thicken existing cell walls to better brace the plant against wind and the battering of raindrops. These matters take time, and that is what hardening-off is all about, giving those seedlings the time they need to make the essential adjustments.

Maybe have the light 18 inches away for most of a week...then drop it down closer to 12 inches. As mentioned before, use your hand to judge if they are getting too hot. Your going to have to water more often with more heat around.

(Just to give credit for the explaination --Thomas Watson is graduate of the University of Arizona College of Agriculture, where he earned a BS in Agriculture, majoring in plant sciences. )

http://www.gardenguides.com/how-to/tipstechniques/seedsbulbs/hardening.asp

 

[DIGITALHIPPY]

When I move my seedlings from indoors to outdoors, I give them only 1/2 day of morning sun for a week then full sun. You have to harden them off. The plants receptors to catch light are geared toward maximum absorbtion using florescent lights and want need this as much with the hid.

Thomas Watson explains...



Maybe have the light 18 inches away for most of a week...then drop it down closer to 12 inches. As mentioned before, use your hand to judge if they are getting too hot. Your going to have to water more often with more heat around.

(Just to give credit for the explaination --Thomas Watson is graduate of the University of Arizona College of Agriculture, where he earned a BS in Agriculture, majoring in plant sciences. )

all this, BUT
STRONG HID MH light grows amazingly strong seedlings. no stringy strechy plants there. i use a 1k or 600wmh...

 

[Tony Aroma]

I too use MH from day one, growing from seed. I have 2 250-w MH bulbs. At first I raise them as high as I can, about 36 inches away, then gradually lower them over the first week or so until they are down to about 14 inches.