If you're going to use an HPS for early growth, just reflect the light up, not at the plants. Keep an eye on them. If they grow stringy, get more light on them, if the grow into shrubs, you win. I use a 600HPS for the entire process. Sometimes I'll throw in floros too.
yeah hps is great ,just dont get them to close .a good floresence is good to .i like using floresence for the first two weeks and switch to hps so i can trick the plant to thinking the the season changing.better chance of females .but this time around i treid hps first and got mostly males
I list the high intensity toward the last only because of the heat and light burn problem. If you are confindent you wont scorch them, and you have the space to keep the lights far away, then have at it. When cloning, you don't want a lot of light. You want the plant to concentrate on building roots instead of photosynthesis. Plants tend to abosorb what they need in the day, and build tissue at night. That's why it's a balancing act when determining the best "on" cycle.
1st choice, MH
2nd choice, HPS with some blue spectrum
3rd choice, flouros
4th choice, incandescant
Flouros work surprisingly well for vegging and produce very little heat. But of course it's nothing like 600 watts of shiney blue light.
The only choice for flowering is the choice between straight HPS, and HPS with some blue spectrum. I've never tried the latter, but I believe it is supposed to keep the plants from stretching as much. I will never again try to use any other light for flowering (except for maybe the sun). It is mostly just a waste of time.
This is all just my opinion, but I am basing it on experience.
I agree with gqone333. That's way too close, unless maybe you have some fantastic cool tube and ventalation. Don't forget there is such a thing as light burn too. You can actually give them too much light and they will curl up and die.
floresence are better for cloning i did a test under a 35watt florences and a 1000 watt. the floresent grew a taller ,hps grew thicker but i had diffrent veireityies the white widow strain difrently grows fast second week of flowering you should know the sex the skunk special doesnt show until the 3rd week. i think its the strains but i have both lights on now.if you have a water heater it difflenty help to grow bigger buds and try to keep your temps between 75-85 80 if possible set you water heater to 23 c. i put a few drops in 5-6 2 times a day for though veg and flowering not to much during veg work your way up.that when you miss you plants .mening when the leaves fell dry , i remeber to trim all the dead meterial on the leaves ,so it wont spread .youlet it get to bad without maintence you got a 20% chance off harvest you trim the dead leaves you get almost 100% succes of harvest .just some tips .if you dont think im right .follow you own judgement .any questions let me know .
do all my vegging under an hps-im vegging 56 young plants under two 400w-shaded hps lights now in a nft system.what ive found works best for me is to keep clones under growlux fluros from the time they are cut off the mother for a few weeks until a good root mass has established itself then transfer them under the hps to get the vegging started,you dont want them under a hps too soon because theyll start trying to pack on the leaf before they have the roots to support the growth.
i also keep 4 mothers under a 400hps light and they do really well.