Help with my stealth rockwool grow-

[The Botanist]

Hi all, long time listener first time caller. I've got two Nebulis Kush plants in 4" Grodan cubes. They are five weeks old, fed Flora Trio and Cal Mag with a few mLs of silica. They are in a stealth cabinet with a very low ceiling, the upper leaves are only 4" from the light, an Ionboard at level 2 is showing 650 ppfd at canopy height. These girls have been very healthy, I thought the leaves looked a bit pale last week I upped the nutrient solution from 1340us to 1992us last week. The reservoir is just 6 liters and pumps over the cubes for three minutes four times a day. Light is 20/4. RH has been 70 percent and the temp has been between 69 and 72 degrees F.
This is my first rockwool grow and has been great until the last couple days- I noticed clawing and then curling and am getting very concerned. I have been chasing the ph, I reduce it by the drop until 5.6 or 5.6. It's usually 6.2 or 6.5 in 24 hours. Having read that as long as it's between 5.5 and 6.8 all is well, I have not adjusted it the last two days, yesterday the ph was 6.7 and the EC 1750us. Today it is 6.4, EC 1769.
Using Apera instruments, calibrated weekly.
I've never done hydro or rockwool before, but I've been very careful and taken notes. I pumped up the lights from level 1 to level 2 last week.
Thanks so much for your advise, I'm at a loss here.

 

[Creeperpark]

Hi all, long time listener first time caller. I've got two Nebulis Kush plants in 4" Grodan cubes. They are five weeks old, fed Flora Trio and Cal Mag with a few mLs of silica. They are in a stealth cabinet with a very low ceiling, the upper leaves are only 4" from the light, an Ionboard at level 2 is showing 650 ppfd at canopy height. These girls have been very healthy, I thought the leaves looked a bit pale last week I upped the nutrient solution from 1340us to 1992us last week. The reservoir is just 6 liters and pumps over the cubes for three minutes four times a day. Light is 20/4. RH has been 70 percent and the temp has been between 69 and 72 degrees F.
This is my first rockwool grow and has been great until the last couple days- I noticed clawing and then curling and am getting very concerned. I have been chasing the ph, I reduce it by the drop until 5.6 or 5.6. It's usually 6.2 or 6.5 in 24 hours. Having read that as long as it's between 5.5 and 6.8 all is well, I have not adjusted it the last two days, yesterday the ph was 6.7 and the EC 1750us. Today it is 6.4, EC 1769.
Using Apera instruments, calibrated weekly.
I've never done hydro or rockwool before, but I've been very careful and taken notes. I pumped up the lights from level 1 to level 2 last week.
Thanks so much for your advise, I'm at a loss here. View attachment 18992941 View attachment 18992942 View attachment 18992943 View attachment 18992944

You need to presoak the cubes in a 5.5 ph before using them. Also, you don't have to hit them 4 times a day only once. Rockwool naturally has a pH in the sixes and will rise after feeding. Just keep the incoming liquid at 5.5 pH and let it rise.

 

[G.O. Joe]

Less is more. Maybe the feed would work with less light, or the light would work with less feed, and who knows what your water needs are, but the minimum is not a bad plan. Shit you not.

HPS rockwool heresy and a tent of freebies

contains no: popular clones or seeds, led, cmh, dwc, lst, scrog, sog, lucas, hempy, or anyone else, topping, defoliation, temperature or humidity measurement, added co2, o2, o3, calmag, tea, booster, silica, vitamin, neem, bacteria, fungus, fungicide, pesticide, bug eating bugs. necessities...

www.icmag.com

 

[Ca++]

The pics align with your description. You raised the feed about 50%, and a few days later they are burning.

Your temps are low, which might be why they were a light colour. The feed increase to explore the situation was too drastic though. I'm not sure how it's 1.8 now, be it you changed things are they ate it down from 2.0 But changes like 50% are a big step. 10 - 20% might of been safer. Just to get a look if they liked it.

 

[The Botanist]

The pics align with your description. You raised the feed about 50%, and a few days later they are burning.

Your temps are low, which might be why they were a light colour. The feed increase to explore the situation was too drastic though. I'm not sure how it's 1.8 now, be it you changed things are they ate it down from 2.0 But changes like 50% are a big step. 10 - 20% might of been safer. Just to get a look if they liked it.

I decided that I had too much calmag. Looked back over my notes and decided to dump the reservoir and start fresh. Took cuttings to clone/top yesterday and decided to remove the airstone from the reservoir. The reservoir was 6.6 yesterday, now it's at 5.6 with no adjustment. New growth looking mottled but vigorous. I left the funky fan leaves on the mothers for diagnostic purposes, they have stopped dying back and look very good. Planning to flip to flower next week, I thank y'all for your help.

 

[Creeperpark]

I decided that I had too much calmag. Looked back over my notes and decided to dump the reservoir and start fresh. Took cuttings to clone/top yesterday and decided to remove the airstone from the reservoir. The reservoir was 6.6 yesterday, now it's at 5.6 with no adjustment. New growth looking mottled but vigorous. I left the funky fan leaves on the mothers for diagnostic purposes, they have stopped dying back and look very good. Planning to flip to flower next week, I thank y'all for your help.

You could remove any damaged leaves so you can spot recovery growth or future decline. Plus the bronzed leaves will attract plant pests into the garden. Some pests love to hide and make their homes in damaged leaves. Thanks, for sharing friend and keep us posted.