Just bad genetics ??

[Steveo h]

I have a four pot RDWC system. My last grow was just a single DWC and went well. I have four super skunks going , three weeks old , two are very healthy , bushy.... two are sickly , small leaves , brown spots , brittle etc. Using advanced nutes , grow , micro , bloom . Good ph but ppm this morning was 131 ?? Also , I'm using full strength. Bad genetics ?

[OzBud]

How are you checking ppm? 131 seems low for full strength nutes for plants 3 weeks old.
For comparison the GH Flora Series drain to waste schedule at full strength should be between 600-900 for week 3 according to their feed chart.

[9fingerleafs]

What scale are you using ?? You all guys need to start talking in EC cause ppm meters have different scales

[Steveo h]

I'm using a TDS Meter. All I have right now . It checks out with my tap water which I know is 97 ppm. I just checked it again..... 121 . Damn !!! But I'm using ph perfect. Advanced Nutrient Rep said ..... don't worry about ph or ppm as long as I follow the rules... which I am.

[9fingerleafs]

What brand and model is your meter? I can help you figure out your scale

[NebulaHaze]

Can you post a picture of your plants in the setup? Sometimes a picture is worth a thousand words when it comes to diagnosing plant problems

I agree it seems like the PPMs are really low, which could mean your plants need higher levels of nutrients. Are you following the nutrient schedule from Advanced Nutrients, or are you using less than they recommend?

[Steveo h]

[NebulaHaze]

The closeup photo with the spots looks like a Calcium deficiency. That could be caused by the pH being too high or too low (5.5-6.5 is ideal in hydro) or it might mean your tap water/nutrient system doesn't have enough Calcium and you may need a plant Cal-Mag supplement (since you're using Advanced Nutrients, their Cal-Mag supplement is called Sensi Cal-Mag Xtra). Needing extra Cal-Mag is relatively common in hydro and coco. Cannabis plants seem to love Calcium.

Also, what do the roots look like for your hydro plants? Are they bone white or do they have spots or patches of brown?

I noticed your coco-grown plant seems to be struggling a little. It looks dry and I wonder if it might need to be watered a little more often? It looks like it could bounce right back with a little TLC.

Overall your DWC plants look good. They don't look nutrient starved, though if you're still using seedling nutrients I'd definitely go to adult-strength vegetative nutrients by now. Like everyone said, your PPMs seem too low for the stage your plants are at. If the plants start getting pale or lime green all over (even though the pH is right and roots look good), that's another sign they need higher levels of nutrients overall.

Just curious, what grow lights are you using and how far are you keeping them from the tops of your plants?

You have a nice little garden developing!

[Steveo h]

Here's some pics since I added cal mag. I'm using two 600 watt HPS set at 250 watt at the warmest part of the day and back to 600 watts at night , ( heat ). I am using full strength advanced trio with all the bells and whistles . The coco is a bruce banner clone. Using GH lucas formula with cal mag and hydro guard.