New Grower Back again... few concerns! curly leaves and stunted growth

[Seanybo1969]

Hey all, Back again with more questions. (Day 22)
Im using 600hps light in a 1.2x1.2x2.0m tent. Im growing 9 plants (3 rows of 3) 5 w/w 3 candy kush and 1 northern lights, they were germed in soil (biobizz all mix) 2 of the candy kush are a yellowish but this is getting better the older they get (pics in old posts) 1 is slightly yellow. 3 w/w are fine and the same size and i have 2 smaller w/w that sprouted at the same time but seem to be much smaller than all of the others. I started using grow yesterday. I have an extractor fan and a desk fan running all the time.
A few of the plants leaves are curling upwards at the edges.. does anyone have suggestions as to what this is... heat burn.wind burn maybe?
The two smaller w/w dont seem to be gaining height.... Ive heard that sometimes they can get nute block from ph lock out.. could this be the case and if so will flushing them save them?
pics attached

 

[RebelRoy]

hey Seanybo.. i`l try answer some of your question until someone more experienced on this field steps in

A few of the plants leaves are curling upwards at the edges.. does anyone have suggestions as to what this is.

most of the cases this is caused due to heat issues. they will curv up to "hide" from the warm light. how far away from top is your light and how hot is it? often, putting a circulation fan up to take away the worst heatwaves from the bulb helps a long way. (theyy dont seem to curv to bad in the pics tho)

Ive heard that sometimes they can get nute block from ph lock out

from the looks of pic 2 i would def check my ph asap...

 

[StickMan]

I concur with RR, as far as heat stress, and checking your PH level asap.

Also looks like you may have some light bleaching going on from your HPS. How close do you have your light to the top of the plants?

 

[armory]

Hey all, Back again with more questions. (Day 22)
Im using 600hps light in a 1.2x1.2x2.0m tent. Im growing 9 plants (3 rows of 3) 5 w/w 3 candy kush and 1 northern lights, they were germed in soil (biobizz all mix) 2 of the candy kush are a yellowish but this is getting better the older they get (pics in old posts) 1 is slightly yellow. 3 w/w are fine and the same size and i have 2 smaller w/w that sprouted at the same time but seem to be much smaller than all of the others. I started using grow yesterday. I have an extractor fan and a desk fan running all the time.
A few of the plants leaves are curling upwards at the edges.. does anyone have suggestions as to what this is... heat burn.wind burn maybe?
The two smaller w/w dont seem to be gaining height.... Ive heard that sometimes they can get nute block from ph lock out.. could this be the case and if so will flushing them save them?
pics attached

Heat stress! im also using same sized tent inside a closet and I have to have a constant 600 cfm pull on it with 300 cfm fresh cold air from outside to cool it down!

 

[Seanybo1969]

Hey folks..our light is 30ins about pot level...on advice I lowered the light by 2ins per day until it was at 30 above the pot...our ph levels are between 6 & 6.4...we did reckon burn fom the light and have now moved the lights 6ins higher so we're hoping this will cure some of the problems we have....we believe the soil we used (biobizz allmix) was/is too strong for the candy kush seeds and therefore some of our problems we are having with those are arising from that...we have just fed our plants the last time using Dutch Pro grow and in a few days we will be changing to Dutch Pro bloom...when changing do we start at a weakened strength and build it up? Thanks again for all the help...Sean and Patsy.....