Seedlings Seem Burnt in Good Soil! Urgent Help Please

i have 9 seedlings, two in soil in which i've grown very well before, and seven in coco. the two in soil are now showing leaf-tip discoloration, indicating possible nute-burn!

The seven in coco do not show burn, but other symptoms which are not in this discussion.

Background and details:
These are 9 days old (from hatching up in rockwool) Hindu Kush seedlings in a standard organic potting soil (with peat, coco, consolidated volcanic ash, "aerators" and "slow release fertilizers" (no indication here, most likely red worms and such). I also mixed some hydroton (expanded clay?) in it to keep better drainage. They are under 400w HPS lighting, and are receiving RO water (80ppm) at 6.5 pH with no additives (except some root juice before planting). Last watering was about 96 hours ago. Besides that, their conditions are identical to those in coco (which haven't show burn symptoms) and they have shown this symptom sometime between 2-12 hours ago.

Like i said, i've been growing with this soil for a couple of months now (bagseed) with no such symptoms (i've had yellowing leaves early at flowering but nothing during veg or seed).

What could be the case then?

The watering before last, which was when planting the cube into the soil, was with mineral water, about 400 ppm. Could this be why? It doesn't make any sense though. Why did this happen? Perhaps a sensitive strain?

and what do I do?

flush the soil thoroughly? I doubt if that would help me get rid of nutes that I didn't put there! or will it? should I try to decrease the soil ppm? to what point?

also: I have 3 seedlings I just put in this soil (with the rockwool cube) 48-60 hours ago. Do I still have time to remove them? or will it stress them much?

please I seriously need helpful advice right now.



You probably can't tell the color but can tell the color difference. it kinda looks like a burn.


A plant growing in the exact same soil (even the same bag) and also without the hydroton. The lesions are not nute burns - they are probably light burns caused by a humidifier blowing directly on the leaves :\


updated better light pics:


above: very small tip discoloration

better plant shot

You may need to post better pics in normal light. Be sure to include photos of the lowest leaves like the pod leaves and single-bladed leaves. Those go first when there's fertilizer burn.

Mother's Finest said:

You may need to post better pics in normal light. Be sure to include photos of the lowest leaves like the pod leaves and single-bladed leaves. Those go first when there's fertilizer burn.

Click to expand...

these are the only leaves! the single blades, right after cotyledons. I can't post normal light for now but you can see it on the first pic, the difference in color. it does indeed look like nute burn!

Sorry, I didn't realize the second pic wasn't a problem plant. Nutrient burn will brown the tips of the pod leaves and move inward, with the single-bladed leaves following suit. Right where that young plant is in the pic is where it starts to need weak nutrients. Yellowing and slow growth at that size often means that it isn't getting them.

Peat, coco, clay & rockwool all need a pH of about 6, unlike normal potting soil's 6.5.

Mother's Finest said:

Sorry, I didn't realize the second pic wasn't a problem plant. Nutrient burn will brown the tips of the pod leaves and move inward, with the single-bladed leaves following suit. Right where that young plant is in the pic is where it starts to need weak nutrients. Yellowing and slow growth at that size often means that it isn't getting them.

Peat, coco, clay & rockwool all need a pH of about 6, unlike normal potting soil's 6.5.

Click to expand...

so you think maybe it doesn't have enough nutes? this is possible, but it makes just as little sense as over-fert, given the data I wrote above (having good plants in this soil), no?

there is one thing - the bag of the soil (same bag the mature plants' soil were taken from) was standing open in the rain. it was wet when i planted them. perhaps all the nutes were washed from it?

you think i should try giving very weak bio-grow dosage to one of them? 200 ppm? 300?

I do appreciate your advice

Mother's Finest said:

Peat, coco, clay & rockwool all need a pH of about 6, unlike normal potting soil's 6.5.

Click to expand...

Peat needs to be 6.5-7.0, 95% of 'normal potting soils' are peat based..............you water at 6.0 in peat(which is naturally acidic) and your gonna get some lockout. Especially P and K during flowering............

some disagreement here, that happens. the more mature plants that have grown in this soil have been given mostly water with ~6.5pH with high success, at least till flowering.

I cannot really tell anything from your pics. Like MF said, the hps light sucks for pics. But I would venture to guess this. Just give them a few days to get use to their new digs. And I bet in a week or so they willl be off and running........

over watering??

cowboylogic said:

I cannot really tell anything from your pics. Like MF said, the hps light sucks for pics. But I would venture to guess this. Just give them a few days to get use to their new digs. And I bet in a week or so they willl be off and running........

Click to expand...

thanks. i'll try and maybe get a sunlight pic if i can this afternoon. they were actually looking lovely and big and green (compared to the ones in coco), and only yesterday i saw this symptom. i'm hoping it will just pass, yes. because i dont know what i can do about it.

update:
for one of the seedlings - it seems to be alright, the burns didn't continue in the next leaves and it seems healthy.

the other plant (already in veg) is still getting more burns in other leaves as well. It still looks very healthy, but the burns are getting worse:



any ideas on this?
can I be sure it's a nute burn now? it's the only plant that has these burns, and i have some others growing in the same brand of soil, as well as others in coco.

what should I do? flush the soil with 18L of pure h2o (6L pot)? will that help? and then gradually start feeding again with organics?

EDIT: I have only one possible (though not very very likely in my mind) explanation: the bag of soil that was put in the pot was standing in the rain for a while. perhaps this triggered time release fertilizers to over-nute the soil? reading a bit more on the subject, it seems like a plausible explanation.

what should I do? It seems that time releasers CANNOT be flushed from the soil! is this the end of the line for my green friend? should I try extreme measures, like washing the soil off the roots and then transplanting into a different medium, or even chop it off from the stem and try to root it as a clone? that would probably not be a viable option though, as it would put him way behind his brothers in this batch.

update: still no progress. don't know what to do.

Did they make it? same shit is going with my girl and I have no fucking clue what I should do...

yes! the problem just stopped at some point.

i'm pretty sure the problem was that the soil that has time releasers was left in the rain for a while which activated the ferts, thus making it a bit hot. luckily my plants came through that, and at some point I stopped seeing those burns. They never stopped growing either.

tell me about your problem.