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Medibud Seedlings Leaves Yellowing & Splotching


New Member
Hello Everyone,

attached below is a picture of one of my seedlings. They're all 2 weeks old, brought up under 2x75W CFL with 6500K, approx. 10 cm above the plants.

Room temps are around 22-24°C, light cycle is 18/6, I water only when the pot feels as light as a dry one, which is about every other day. Started them off in jiffy pots, moved them to pots with CANNA seed soil & perlite, NO added nutrients.

They were doing absolutely great until yesterday, I noticed a yellowing in a couple of seedlings. Today, the first grey blotches appeared all over the leaves. The most developed seedlings seem the most affected.

Is this bleaching? Do they suffer any deficiency? I fear for my babies' lives!

Thanks a lot for your help!



New Member
As I said: I water them only when the pots feel light (I have a dry pot next to them for comparison). By coincidence, I took this picture a couple of hours after watering.

I've searched the web for literally hours and couldn't find this exact condition in seedlings anywhere. The seed mix I use is supposed to be ph-balanced and perfect for these plants, the perlite adds drainage and aeriation so the roots should be doing fine. I've added no nutes at all, so I guess there shouldn't be nute burn here.

And yet: those leaves are dying.


Member of the Month: Mar 2011
It's definitely not bleaching or overwatering. To test pH, you should really check the runoff to see what's going on.

I'm not familiar with the type of soil that you are using. Does it have nutes in it? Your girls might just be hungry. It looks to me like N and P deficiencies. They probably just need to be fed.


New Member
Thanks, Hemp. That seed mix contains a lower dose of ferts than other pre-fertilised soil, but it does contain everything you should need during the first couple of weeks. I'll transplant some of the larger girls into a real veg mix later today and see how that goes.

In the mean time, some updates: Flushing seems to have corrected the pH desaster, runoff is a good 6.2-6.5. The conditions have not worsened, in fact new growth has resumed on some of the less stricken plants.

Pics below, the topmost is the most stricken.



New Member
Good news: Flushing seems to have worked. In addition, I started giving them a very low dosage of nutes in case they needed any.

Next time, I'll forget about jiffy pots, start them off in seed mix and move to regular pre-fertilized soil as soon as the third set of leaves appears. And pH my water, of course...

The plants are looking much better now, new growth has resumed, the most afflicted leaves are wrinkling away while newer leaves look and feel as they should.

I just hope I didn't hermie my girls in the process... ;)


New Member
Hey guys, just a quick question, should my ph runoff be right at 6.5 which is my goal or should the water im feeding them be. I fed 6.5 phd water and the runoff was 6.9. does this mean that i need to undershoot the water i give to compensate for the higher soil ph?
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