Adjust rockwool PH after planting

hicksy

Well-Known Member
Is it possible to adjust the ph of rockwool after a plant has been planted?

Runoffs are going higher. first grow. didnt adjust ph pre hand. :(
 

mygirls

Medical Marijuana (MOD)
Is it possible to adjust the ph of rockwool after a plant has been planted?

Runoffs are going higher. first grow. didnt adjust ph pre hand. :(
if your runout phishigh then just water with ph'ed water just like you would any other normalfeeding or wateringday. if your ph is low just adjust with your ph UPtell itis were you want it. good luck:hump:
 

hicksy

Well-Known Member
yeh think the rockwool ph causes higher runoff. im using a return sys into res. so its causing the res ph to rise daily.

so i should put ph at an even lower level?
 

mygirls

Medical Marijuana (MOD)
yeh think the rockwool ph causes higher runoff. im using a return sys into res. so its causing the res ph to rise daily.

so i should put ph at an even lower level?
im asoil grower but you should change the res every week or two. that should fix the ph problem
 

hicksy

Well-Known Member
ta mate.

Yeh i change it weekly. its only had 1 change so far. but ph is still rising. i might just do another change anyways and lower ph down abit further. so by the time it runs back into my reserve it should be the correct ph. i just hope that means it will be the right ph range as the plant is taking the food untill the res becomes right again and the ph of the rockwool as settled
 

mygirls

Medical Marijuana (MOD)
Rockwool cubes

How Do I Prep My Ebb & Flow Table, using big rw cubes?



Contributed by: SOG

Rockwool Prep:


In this application, running tight spaced cubes with the intention of doing a spike type, mostly single cola grow, 218 cubes are placed into the table. Thats a full table, less 2 for the fill/drain holes. The tray is first flooded to the top of the cubes, with water at PH 4.7 and allowed to stand for 12 hours. This helps keep them from drifting up in PH. They are then flooded with straight tap water to rid of any debris that may have come in the manufacturing or handling of them. Next they are flooded with PH 5.7 water, at this time the cubes should be at PH 6 and ready to accept clones. This is also a great time to check that your table is level.




Each table is a standard 4'x 8' ebb & flow with 2 x 1000wt HPS air cooled lights. Air stones are added to the table and large four inch rockwool cubes are the medium. The cubes are covered with mylar and "X" cuts into the holes that accept the 1" rockwool cubes. This is done to help keep the roots dark, keep the algae growth down and to reflect a light back up to the plants when they are small. I use a very small submersible pump for pumping the water to the table, a couple of shut off valves are also helpful to control the flow and also keep the water in the table for PH adjusting the cubes. A digital timer is used here so that the flood time can be adjusted to the minute.





Above dual picture, shows prepared table with pre-vegged six inch clones inserted and ready to go. Tables are flooded one hour after lights on and again every two hours after that for a total of six feedings during lights on, nothing is used at night. Flood height is adjusted to roughly three fourths of the cube height, and takes just over six minutes to fill, pump runs for eight minutes.

Added on: Saturday, March 24, 2007 Viewed: 1662 times
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hicksy

Well-Known Member
Thats awesome info mate. will keep in mind for the next batch. unfortunately as i was saying my plants are already about a month from seed :(

already in the RW and in hydroton pots

Is there anything i can do now? Just keep flushing?
 

sfjohnson

Member
Thats awesome info mate. will keep in mind for the next batch. unfortunately as i was saying my plants are already about a month from seed :(

already in the RW and in hydroton pots

Is there anything i can do now? Just keep flushing?
I have the same problem. I've been doing a pH down on my res daily but it keeps popping up. Finally determined that it's the rockwool and upon checking the pH in the E&F buckets - sure enough, it's about a full point higher. :wall:

Tomorrow I am going to treat some fresh rockwool and then replace the majority of the stuff I have in the pots. Will then flush the entire system while the pots are removed and introduce new water. I'm hoping that this will replace the untreated medium with the "neutralized" stuff and my pH will become controllable.

I'll let you know how it goes.

The other alternative I considered was trying to just treat in-pot during an extended flood cycle... but that just feels dumb for some reason. Seems a better path to simply deal with a little short term stress to root out (pun only partially intended) the problem...

... and then never to forget to prepare our rockwool again!

- S
 
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