i would bet that that 600 watt light is bleachingthe ever loving shit out of them at 12" to 15" away from the canopy, even blooming plants like the 600 watter @ least 18" away, if closer you get MAJOR stretch with a 600 watt hps that close(when budding that is) after stretch period(1st 2 weeks of 12/12 you can try and get it around 12" or so if properly cooled hood is in effect)
same shit happend to me i was using rockwool for years and then all of a sudden it seemed like i turned back into a novice with rockwool.
they say the newer rockwool thats made last and this year ('07-'08) is cleaned up like the "AOK rockwool starter cubes" from grodan.
when i say cleaned up i mean they have pre-treated it and leached all the petroleum and limestone residue out of it.
when we (growers) soak rockwool we are told to soak it over night in a weak nute solution with a ph of 5.5, then rinse each block out with freshly made nute solution @ ph of like 5.8 then plant seed orstick cutts.
the reason for this is because of the left over residues and such from the manufacturing process (the petroleum, limestone and adhesives to keep the block tight and together).
rockwool when fluched and pretreated properly, will have a neutral ph and you can , orshould be able to water it at a ph of 6.0-6.2.
now when soaking rockwool that needs to be soaked before planting in,they say to use a weak nute solution, this is because the nute solution (water and nutes) is buffered a little so it is not as likely to turn the ph of what the block is. where as on the other hand if i were to just use straight "RO" water or distilled water and adjustitsph to 5.5 for soaking, as soon asit got in the blocks it would immediatley takeon the ph of the block, becaseu there is nothing in the water other thatn just a little bit of ph adjuster to buffer the water.
so thats why i quite with the rockwool, it has to many variables.
like: "i just got some ROCKWOOL at the hydro store, now is this old stock that will need soaking or is it new stock and just need to be planted in?" then if you soak to low on the already pretreated ones you can dammage the fibers in the block and then you will always be fighting PH swings cuz the blocks fiber's integrity is comprimised.
hang that light higher and flush with some clearex, i would usually recomend final faze or flora clean as the flushing agent but thay are to harsh in this situation, where as clearex is sucrose and glucose based, and will do the job you need done right. only 9 buck a quart.
flush with clearex, then flush with plain RO or distilled (to get the clearex out of the system, then hit em iwth 1/4 strength nutrients. now when i say quarter strength i don't mean take the higest bottle recomendation and cut it to a 1/4 of what they call for , but add nutrient to water and check with a meter till it gets to about a quarter strength of what marijuana usually grows best at, which is about 1200-1400 ppm @ .7 conversion factor, where 700 ppm = 1.0 ec. so you want about 300-450 ppm which would be about 0.55 ec or so no more than .60 ec sor the first 2 weeks. but you know this as you have been growing for 5 years or so. but the seed you have may want a lot lower of ec strength than what you are used to growing, thatswhy i never go by the back of the botttle, instead i just measure the actual strength with a meter before giving it to the plants.
nute manufacturers, i dont care which one itis, always try to get you to use as much nutes as possible per cycle without killing your crop (sometime they dont even care they just want you "throwing"nutes at the plants) so you ultimately have to by more nutes more frequently. |