How far should my lights be?

[chronic_zhen]

Im using 2 of those curly tubed energy saving 100w output bulbs for 2 plants, how far should they be from the soil? and how far should they always be from the top of the plant?

[Sunstar]

I'm not sure . I have never used that type of bulb. Maybe the best way to insure the best result would be to place a thermometer about a foot below them and check to see what the temp is. Best result happen when you keep the plant at a steady 75 degrees. Do you have a fan blowing on them or away from them to draw the heat off? I have heard its best to draw the air away from.

[Tsering]

I'm new to 'topia (Hi Mycrotopia!) and growing as well, but in the Overgrow Archives posted in the sticky thread at the top of this GrassRoots forum it says that compact floral bulbs, as you have described, should be placed within an inch of the top of the plant.

I confirmed this report using a cheap-o light meter that came built in with my moisture meter. The meter showed no reading until placed within an inch of the bulb.

[chronic_zhen]

1 inch? i dunno scares me that i might burn the lil tiny thing when it pops out the soil and im not there, the soil feels warm on top i think they are doin the job, as for ventalation these dont put off much heat and my closet sticks out from the wall and there is no top on it, i keep my room fan on at all times to kee proom circulation, and during light hours i sometimes keep the closet door open with my pedistol fan blowing air towards the door from like 8 feet away cuz i dont have a plce to plug it closer and no more extensions lol, well i guess ill find out if they dont pop out the soil and reach for light, right now there like 2-3 inchs cuz like i said im scared of killin the lil ones when they pop up, i already germinated so hope i see some results soon! thanks for the suggestions

[StroFun]

i put a 75 watt flouro 1/2 inch from my salvia plant with no fan and no problems but i have a plastic light diffuser on the light that allows about 1/4 inch but my sally grows right up against the diffuser. If i don't hack mine up into cuttings i'm going to need to get 2 more of them or go HPS.
Just start with 2 inches even and then gauge it by the seedlings growth. If they grow tall and fall over obviously your light is too far away. If they start to burn obviously move your light farther away. Sometimes you have to make some sacrifices before you get the hang of things.

[chronic_zhen]

yeah i understand its a learning process, its just that its a super cheap setup, and i only did it cuz im really hurtin for some buds, and i wont have the extra money for a while, and these are the only 3 seeds i have my ex GF stole the other 17-18 i think GRRRRRRRR plus im gonna have to stick with these compact flouros through the whole life of the plant, im gonna foil line the grow box once the seedlings pop up to hopefully spread out the light and, so im just really trying to do everything i can to make these survive

thanks again for the advice guys

[Godflesh]

1" for the first 3 weeks of life.

[Sunstar]

I heard you post if they pop outta the soil.
I have been told if you take 4 papar towels, lay 2 of them on a plate and wet it down with warm water, place yer seeds on the plate and put the other 2 paper towel over top them. Then turn the plate and let the excess water drip off of it then place in a plastic shopping bag like the ones you get from the grocery store.
allow a little air in the bag and spin it to keep it shut. Place bag in a warm spot like above or near yer lights. Within 7 days the tap root will show and yer germination rate will be much improved. Place seed root pointing down into the soil with the seed just sticking out of the soil and give a light spray with water to ensure the soil surrounds yer lil root then cover sprouts with celaphane and put under lights. It will work out very well for you.
The plant really doesnt need light or air till it gets it first leaves so you can keep the seeds on the paper towel in a warm dark spot till the lil tap root appears.Once the first leaves appear loosen the cellaphane to allow air in. Its best to not let the tap root grow over a quarter inch to a half inch in length.

[chronic_zhen]

Oh yeah i already germiated in paper towels, these puppies showed nothing 2nd then then suddenly massive tap root in 3 days! so hopefully they will be some fast growers too! And actually i just went to turn my lights on and 2 have poped out the soil today with there seed leaves!

Now that i think about it....i started germination Monday, here it is Thursday and they are already 1/5 in tall is that pretty fast?

[doobydoobydoo]

Originally Posted by chronic_zhen

Im using 2 of those curly tubed energy saving 100w output bulbs for 2 plants, how far should they be from the soil? and how far should they always be from the top of the plant?

Very simple, as close as possible to the plant tops without stressing them or burning them. A fan moving air will greatly reduce the temps around the bulbs and plant tops and also make for far stronger plants and insure constant fresh co2 around the leaves. With floros like that you need to get fairly close.

With light, the further you move away, it exponentially drops it's strength. Even 1" or 2" can mean such a huge difference. I forget the exact formula, it's like it cuts in half each segment you move away from it or something. Keeps halving it self.

I've seen a 400 watt setup where someone was only getting 16,000 lumens on their plant tops, they moved the plants 4" closer using whatever they could find to raise them since the light was as low as it could get. The light at the tops was near 25,000 or more after the lifting!

That's 9,000 lumens! (this is from a light meter reading), That's a lotta lumens, esp if you run low watts. So closer, the better as long as they don't stress.

Signs of stress will be the leaves curling and burning and/or wilting and drying out from direct contact with a hot bulb. Another sign, if they are too far, the stems stretch to try to get closer more so than bulking up.

So, keep the as close as you can, even from the start, as long as no stress. And, to reduce the heat, air movement via a fan works awesome all around.