Slow growth and yellow leaves - need help

[tsox]

I planted the seeds on the 19/10. Now, three weeks later the tallest one is 20cm. I use 4 400w HPS and I light them 2 at a time (18/6).

Temp: 28-31 C
Humidity: 50-75
Air-Condition is used and an oscillating fan

I water them every 3 days (PH 6.5)
The soil I used is Biobizz all mix.

At the beginning the lights were a meter higher than the plants, and now I put then at 70cm.

What's more, they don't seem very healthy.. Some leaves have turned yellow.. and most of them seem to still be seedlings!!!

I haven't used any fertilizers yet.

Could you please help?????????????

 

[fish cake]

can you post some pictures?
also what kind of lights? they sound as if they are too far away.
but more info is needed for anyone to give help and advice

 

[tsox]

as i wrote above i use 4 x 400 watts DUAL SPEC HPS lamps. what other info do you need? i will post fotos in few hours as soon as the lamps are on.

 

[tsox]

the prob is that i ve got stretched plants with tinny leaves most of them are yellow with green vains. some leaves are twisted too.

 

[Muttt]

Sounds like they need more nutes and more light. But, hard to say ..... what does your setup look like.

 

[tsox]

the soil i use is bio bizz all mix. it is allready pre-fertilized and there is no need for feeding for 3 weeks. i am now on the 3rd week. i have a small grow room 12 square meters and planted 19 ladies in 18 lit pots. i really dont realyse what seems to be the prob. exept the fact that the lapms were too high until today. after all this info can someone tell me what is going on?

 

[tsox]

can the lack of light couse such problems like streched plants with tiny yellow leaves and green vains some of them twisted too? us i wrote above im on the 3rd week and most of them seem to still be seedlings but streched ones!!!

 

[tsox]

in about an hour ill post some fotos too

 

[fish cake]

some sounds like to much or even to little water and yes if the light is to far away that will make the plant reac for the light.
after some pics someone here will be able to give some kind of help or suggestions to help your grow.
everyone here has it in their best intrest to see a fellow gardener succeed. at least I do

 

[tsox]

thanks fish cake ill post some pics in a little while. hope to talk with you couse thats my 2nd grow and i really need to have healthy plants

 

[fish cake]

hey bro not to toot my own horn but if you go to my thread there are a lot of folks that visit me, they will also try to get your grow on if you ask

 

[tsox]

 

[fish cake]

almost looks like a P or K diff. but they are way to young as far as I can tell.
thats my guess but now you have pics up someone else should chime in

 

[tsox]

..Thanks, but what could cause this P or K diff?? I am asking because I am using pre-fertilised soil and the water PH is 6.5. Should I check the EC value of the water?

 

[fish cake]

sure why not brother
to tell you the truth I have never bothered with ph,ec ml or any other of that stuff. if it looks bad I have always just compared it to what other folks grows are like or remembered what someone suggested. the last thing I will do is to tell you how to fix something I cant say for sure is wrong. I would never feel good about helping screw someones grow up! so thats what I think but it may not be right

 

[tsox]

Thanks mate