Question on "Bubbleponics"

[Panos]

Hi all-
I am a first time grower.
First attempt was with CFLs.
Got one seed to germinate out of three. Was doing fine till i thought it has reached the vegetative state then I got nutriment burn. [At least I think thats what ailed it.] Flushed and now trying to revive it. Just giving it plain water with correct pH. I hope it will revive.
In the mean time read about 'bubbleponic' method Top-Fed DWC Cannabis Setup Guide - Bubbleponics | Grow Weed Easy and got intrigued. So am currently in the process of setting up such a system [waiting for the various components,etc].
OK thats the intro.
My question is:
During the germination stage, at what point does one turn on the 400w MH light?
Have read all the pages, links, etc especially How to Germinate Cannabis Seeds in Marijuana | Grow Weed Easy
But other than: "leave seeds in dark or use an incandescent bulb",see no specific mention of when (at what stage? height?) to turn on the main grow light (400W).
Apologies, perhaps I missed something but would greatly appreciate some advice on this. Only have 3 seeds left and hate to make a mistake--
Regards,

Panos

[IanHale]

I turned my light on when the first two round leaves pop.

currently I use 1 of my two 2 600w MH/HPS. My seeds popped out of their rooters quickly and for 4 days I kept the light about 4 feet above them. I lowered my MH light down to about 14" to prevent anymore stretching. I should have lowered it two days earlier.

[DW2]

Howdy Panos, and welcome to the forum. I am currently on my sixth DWC (Bubbleponics) grow. I germinate my seeds on a wet paper towel in an aluminum pan. The water is pH'ed to 5-0 and just enough is added to the pan to cover the folded paper towel, but not enough to immerse, or cover the seeds. I cover the pan with plastic wrap and then foil to block out the light. Keep it in a warm place around 75°-80° F. After they sprout, I transfer them to rockwool cubes (with a small amount of rooting gel in the hole) and place them in the net pots. I use a bottom feed irrigation and cover the net pots, Hydrotron pebbles, and all with aluminum foil to block out the light. Keep the water well aerated and the temperature below 70° F, keep the pH between 5.5 a 6.5, and completely drain and change the water out each week. As Your plants grow, add only pH'ed water (@ 6.0) to top off reservoirs between feedings. Here are a couple of photos of the current and a past grow.

[Panos]

Thank you for the info--nice pix-- will keep your technique in mind when starting germination.
But I'm still looking for some 'guidance' on when to turn my main (400W mh) lights on.
Is this just when one is 'satisfied' that the germinating seeds have grown a few leaves / reached a certain height?
I suspect that I have answered my own question but since I have no experience with growing, would like some 'reinforcement.'
Thanks again
Panos

[DW2]

I use CFLs (220 watt each reservoir), but I keep them at about 12", until the sprouts start to stretch. I would guess that one would want to keep almost twice the wattage a little further away, until they get the third or forth set of leaves on them. That is how long I keep my lamps at 12", then move them in close, about 3" to 4" above the plants. If Your lamp is not air cooled, You may want to keep it farther away due to the heat generated by a MH lamp.

[D.A.A.S.69]

When you first see anything green growing turn your 400 on ,they don't need light if they haven't come up. Nebula has plenty of information on light distances look under LIGHTS ,she will tell you how far to keep it above your seedlings, if I had to guess I would say 14 to 18 inches above them till they got little older then bring your light down some. Hope this helps some Panos

[Panos]

It helps a lot. Believe or not I've spent days up and down nebula's pages clicking on the links (imo I think there are too many) but never found the specific information that you gave me. Currently waiting very impatiently for all my components to arrive -- so I can start making mistakes!
I do have a question on the manifold for hydro system but perhaps I should start a new topic.
Again, many thanks for your input, appreciate it.

[POKEDSMOT]

Welcome Panos. As stated before once the cotyledon show give them light. If you still have the CFLs you could put them damn near right on top of them and be good. I have a multi watt ballast 400/250/150 on 150w @ 12"-16" until the first true set of leaves come in then 250w @16"-20" just to give you an idea of what has worked for me. No light burn or stretching.

[D.A.A.S.69]

Hey Panos , look under lights right at the beginning. She has distances for every light you can think of especially HPS lights of every watt. It's there ,Good Luck

[Panos]

Thank you for your response.
Yes, I've noted the distances you mentioned. My question (probably poorly stated) was: when to turn on the lights after placing the seedlings in the rapid rooters.
I've got my answer.
Thanks again.

[Zativa]

Going through something similar with an heirloom variety that seems to need **LOTS** more light than others I have grown. With my LED fixtures at normal distance, the plants kept trying to grow tall and spindly. Had to lower those lights way down close to the seedlings, now they are working on a few more leaves. Watch the plants, they tell you when they are getting what they need (or not).