Rockwool problem def.

[STLbudz]

What up guys still tryna get a hang of this rockwool game .. anyway every time I feed my plant the bottom leaves seem to shrivel and yellow , put new growth seems fine every watering it the older leaves wilt n yellow plus I can't solve my phosphorus issue ...? So I been feeding at ph 5.8
2ml cal mag / 2ml An sensi grow a&b and a little silica blast for ph up strain is purple punch

 

[STLbudz]

Just checked my ph pen it was off by 2 so I was actually putting in 5.6 instead of 5.8 I'll post back to see if this helped

 

[STLbudz]

So I've corrected the feeds to 5.9 and ph is calibrated correct .. and the phosphorus lockout seems to be clearing up a bit , but the lower growth seems to shrivel or yellow out as soon as I feed ..? Any input ?

 

[JDMase]

http://www.growweedeasy.com/nitrogen-deficiency-cannabis


I had the same thing with tangie in rockwool. Just fed nitrogen and it cleared up quickly.

 

[im4satori]

for now im just guessing

I think your under feeding across the board
and I betting your nutrient ratios are out

lets get some more info and get you straight!
id been in rockwool forever

the silica is likely also giving you trouble

theres a delicate relationship between potassium, calcium and magnesium

adding silica adds a large amount of k and can easily throw out the balance between these elements
theres also a relationship between K and N which could also be a smaller factor

I need some info on the sensi part a&b
either take a picture of the label of each bottle showing the listed % for each element and post it so I can see it
or clearly tell me what it says in a way that's easy to understand
for example

part A
N.........5%
P.........2%
K..........7%
Ca........2%

and so on

 

[STLbudz]

@im4sato I'll check that tomorrow , have no idea lol ... but yeah I was checking run off and it was 6.3-6.4 I flushed it last week and feed 5.8 this am came out 6.0-6.1 so look like ph is getting better . Stalk is clearing up but have some stripping .. trying to dial this in lol ??? Rockwool lil difficult ??? , all my soil plants are killing it !!!!

 

[mjinc]

What EC or ppm are you feeding your plants?

 

[im4satori]

@im4sato I'll check that tomorrow , have no idea lol ... but yeah I was checking run off and it was 6.3-6.4 I flushed it last week and feed 5.8 this am came out 6.0-6.1 so look like ph is getting better . Stalk is clearing up but have some stripping .. trying to dial this in lol ??? Rockwool lil difficult ??? , all my soil plants are killing it !!!!

that small a ph difference isn't an issue

if your anywhere from 5.4 to 6.2 your good

the fact that your ph is rising

5.8 going in and 6.2 going out is a positive thing...as in good..thats what you want

are you running a closed/recirculating reservoir or an open drain to waste system??

what that might tell me is your likely feed an appropriate EC/PPM
you might need to water a little longer duration each time you water
the longer waterings will bring your RW ph samples down a bit

but it doesn't explain a nutrient issues or imbalance
I suspect (since your using silica) you've got in imbalance in the potassium, calcium , magnesium ratios

when you get the nutrient mix balanced the rockwool is easy enough