125W CFL distance -newbie Q

[Delta9]

My beans are popping- and Im getting ready to drop them into soil and shift them into my tent under a 125W cfl.

Now- there seems to be a lot of varied opinion online about the best distance from the cfl to the top of the soil/seedling.
Some say 2-3 inches, some say 5-6 inches and others 18 to 40 to 80 inches!

I would love to get a consensus about this from someone here-

 

[Delta9]

My apologies for the elementary question-i am sure veteran growers will be like... duh?! !faceslap! i know...
But I would like to get the lamp in the correct range
My setup consists of a 6ft tall, dual compartment tent
The upper, smaller section will be devoted to clones eventually-
For now my seedlings are up there with the cfl..
The larger "downstairs" compartment will house my veg to flower HID.

As far as I am told the cfl's run relatively inefficiently
Which makes me wonder whether closer with the lamp is better..?

 

[Delta9]

"Marijuana Horticulture - The Indoor-Outdoor Medical Growers Bible" states 2-4 inches for a cfl such as this -mounted vertically is apparently more efficient for this bulb.

In the absence of further advice,
I will go with that.

 

[BenfukD]

lower light above the plants canopy. place your hand over the plants. If it is too hot for your Hand than its too hot for the plants. I think My cfl are around 5 inches away. Do you plan to use this light for the grow? Best of Luck

Ben

 

[The Hemp Goddess]

Is the 125W actual wattage or is it equivalent wattage? This makes a huge difference.

A 125W CFL is going to put out more heat in one spot than a bunch of smaller CFLs or fluoro tubes, which spread the light and heat better. CFLs lose light intensity over a small distance, which is why you are encouraged to keep your plants as close as you can to the light. At 80" I doubt that the plant would be receiving any significant light--you would have a tall stretchy plant with very few internodes.

Smaller seedlings are going to need to be further away than established plants--they can burn up before you know it. I would start at about a foot and then lower it a little every other day or so if the plants show no stress. Take temperature readings at the canopy. Generally speaking, we tell you to put your hand under the light and if it feels too hot for your hand, it is too hot for the plants. Be cautious with seedings. In fact, if you have some lower powered CFLs lying around (I use them for all my household lighting) you might want to start the babies with something that will be cooler.

Are you going to have enough light with the 125W?

 

[Hushpuppy]

I totally agree with all THG said. It is a balance of heat and intensity that you have to maintain on the seedlings. Make sure you have a fan circulating the air in the clone space. And if you close it up then you will need to put a small exhaust fan to pull the heated air out of that space so that fresh air comes in. There are several options for that fan but don't get the "duct booster" they just don't work for suctioning of air.

 

[Delta9]

Thanks everyone for your input

I found this info finally-

hxxp://www.enviro-gro-lites.co.uk/stuff1.asp

And it illuminates the subject rather clearly

 

[Delta9]

Is the 125W actual wattage or is it equivalent wattage? This makes a huge difference.

A 125W CFL is going to put out more heat in one spot than a bunch of smaller CFLs or fluoro tubes, which spread the light and heat better. CFLs lose light intensity over a small distance, which is why you are encouraged to keep your plants as close as you can to the light. At 80" I doubt that the plant would be receiving any significant light--you would have a tall stretchy plant with very few internodes.

Smaller seedlings are going to need to be further away than established plants--they can burn up before you know it. I would start at about a foot and then lower it a little every other day or so if the plants show no stress. Take temperature readings at the canopy. Generally speaking, we tell you to put your hand under the light and if it feels too hot for your hand, it is too hot for the plants. Be cautious with seedings. In fact, if you have some lower powered CFLs lying around (I use them for all my household lighting) you might want to start the babies with something that will be cooler.

Are you going to have enough light with the 125W?

125 actual wattage I believe. I took your advice and lowered the light incrementally to get the right balance of heat and light.
I have them sitting around 6 or so inches away at the moment and two sprouts have broken the surface of the soil so I will be keeping a close eye on them to avoid stressing or frying them. The 125W will be plenty of light for this small compartment I think...At least I hope so! The height in this area is only 60cm in total and I not filling the rest of the space [80 x 120cm] entirely with seedlings-just six seedlings in a propagator tray so maybe in about a week or so I will move them downstairs to the HID.
Its moving quickly into winter here now and the temperature under the light shifts from about 25 Celcius during the day to 18 Celcius overnight..
Thats seems not too bad considering its 8 degrees outside tonight..brrr

 

[Hushpuppy]

That sounds good. Just don't let it drop below 18c and keep the light on continuously (24/7) while they are vegging and the warmth of the radiation will protect them if the temps do drop below 18c

 

[The Hemp Goddess]

You are probably not going to want top put them under an HID at a week--they are still to small and fragile.

Be wary about hype put out by bulb manufacturers. I had an enviro bulb many moons ago and they are simply not all they are supposed to be (actually no better than any other CFL, just bigger, which is not an asset, IMO). For instance, you could never save money over an HID with fluoros. When you have enough light from the fluoros, you are using way more watts than if you were using HID. They also do not really give you any real information about the light either--just keep saying how good it is. We don't know the spectrum, we don't knowe the lumens, etc. However, you are only going to be using it for a short time in a small area so I am sure that it will work just fine.

LOL--it is going into summer here and I still have temps colder than yours--30F last night or in your neck of the woods, -1 c. Brrrrrr. Your temps are good and the seedlings should like that. Since it is only 1 bulb though, the heat and intensity are concentrated, so keep a close eye on the babies and don't let them dry out.

Sounds like things are going good.