twisted yellowing leaves, stunted growth (pix inside)

Hi there. 1st post of a long-time lurker.

We had a crisis with heavy metals contaminated weed polluting the market around here not too long ago, so I decided to not buy anymore and grow my own ... again, but this time indoors and with proper equipment.

So right now that's 3x Maroc/Skunk Special plants grown from seed in a DR60 vegging under 2x55 TNeon lights + one plant from the freebies. The plan is to keep 2 plants max and SCROG 'em.

They're each in 2,6 gal containers (10l), same soil mix (quality potting soil, PH-neutral, added 20-25% perlite), same nutes, same everything.

I feed them with every watering (once a week for now) with BioBizz Grow (5ml per liter) and give them some extra nutes in between by spraying them with a 2ml per liter solution of the same stuff.

PH seems to be be between 6 and 7 (kinda hard to tell on those strips), RH is between 50-80% (I humidify from time to time), temps are 25-29°C near the leaves (at night it's around 20-22°C). I have a small fan in the tent to keep a steady air flow, extraction is not installed yet, but will follow (right now I have airflow via stack effect, there's this chimney-like openening in the tent)

The soil reacts normal to watering (I let it dry out until the pots feel light, then water/feed 'til there's a little runoff).
I water with a mixture of tap water (hard) and rain water (very soft) to keep the PH balanced, but that might be redundant, dunno ... that's how I used to do it, and it worked.


They're 6 weeks now (veg), and apart from being kinda very bushy and not very high (12"), they look great so far. All but one! One has twisted leaves with yellowing margins, some superdark, clawing leaves too, and stopped growing a week or more ago (see pictures, it's about it's only about 8").

The others had those twisted leaves too, but only directly after repotting ... they straightened out, so to speak, over the last few weeks.

Granted, they all had a terrible childhood: the seeds had arrived but no equipment yet ... and impatient to start (I know, I know, bad attitude), I grew them in what turned out to be terrible coco, so all of them looked really sad & sick the first two weeks of their miserable lives. 2 pf them even died.
I repotted the the remainders in quality ph-neutral soil with 20-25% perlite ... BAM! they grew like ... well ... weed. All but one ...

So HELP! What's their damage? Reading through the forums made think it might either be a Zinc defiency, maybe Magnesium ... but I have not really a clue actually.

Any help appreciated. Thanks

PS: there don't seem to be any signs of pests, neither on the plants nor in the soil

Nutrient burn IMO.

The leaf tips do look like a possible Mg issue. The curling/twisting of the leaves looks like a burn.

I would continue feeding at a lighter dose maybe 3ml per L , cannabis doesn't need a lot of nutrients.

I would also recommend that you stop spraying your plants with nutrients. I would only spray neem or in case of an emergency as in a severe deficiency. But not to provide primary nutrients (NPK).

It is possible that the inert coco caused the MG issue. So in your case I would spray some epsom salt minus the others nutrients of course.

Lastly in soil I feel it is best to provide a lot of run off as to a little. No to little run off causes nutrient buildup/lockouts more than a full watering/ alot of run off IMO. Unless you have bluemats or something of that nature. This I know hasn't been proven, just a hunch.

Anyway, your plants look great other than the burn, let me know if you have any other questions.

Take care.

nute burn you say? hmm, that's possible. when I re-potted them they looked so miserable, that I bumped the nutrition from pretty much nothing to 5ml/l ... probably too much in too little time

So I'll cut back on the nutes and I got me some all-around trace nutes solution (with 9% MgO) which I will carefully apply with the next watering, then wait and see what happens.

The package says 1g/20l so I'll go with half or less of that and see if it's doing any good.

and more runoff, got it. Thanks, Big Brotha P

anyone else have any ideas or wants to weigh in?

the healthy plants are growing just fine, I need to raise the lights pretty much on daily basis ... now I need to find a solution to get the smaller plant close enough to the lights to support its healing process

it's a wonderful, relaxing hobby ... if everything goes according to plan

hiya all, i would be careful of the age of your rainwater,symptoms you described are very similiair to what i experienced a few years back,after ruling everything else out, the rainwater i had been collecting over a couple of weeks which i used with normal tap water [plus nutrients]appeared to be the culprit, i may be wrong but after fucking off the rainwater after a short while, all was well, peace and regards s2

I see the following;

Reddened/purpled petioles--indicative of N/P -/+.
Leaf margins yellowing, appears to be on upper leaves only--Mg-.
Leaf tip burning--N+.
Leaf twisting, torquing, crepey texture--pH parameters are off (stop using strips, they're useless, get colorimetric drops or a proper meter if you're going to adjust pH at all).

Why are you giving additional foliars of the same mix?

How familiar are you with the feeding/nutrient requirements of working with coir? Actually, your post is confusing because first you say they're in quality potting soil, and then you say they're in shit coco. Which is it? They're different beasts that perform differently.

Either way, all is not lost. STOP FOLIARING NUTRIENTS ON TOP OF FEEDING. Sorry, I feel that must be emphasized, because for me the strength that you've been foliaring at is where I would have begun feeding them.

If it's truly coco coir in which they're growing, then know that the pH is VERY off. By a full point. The best pH range for soil cultivation is about 6.2-6.8, whereas for coir it's solidly in the 5.8-6.2 range. While it's not bad to allow ranging outside those parameters at the occasional feed or water, it's absolutely detrimental for all feedings and waterings to be out of range.

Tell us how you started off that coir, why you say it's shit coir, and get the pH monitoring and manipulation thing sorted out. Those additional bits of information can guide what your best next steps should be. For example, it may not be a good idea to flush at this time, it may be better to simply reduce EC of the feed by at least half (I'm thinking equivalent to 250ppm/.3EC, or lower), and ensure it's balanced for Ca and Mg as well as pH being within parameters for uptake of nutrients.

It's very important for plants to lay down sufficient Ca early on, because it's an immobile element which must be translocated from older tissues into new growth, and this is an additional concern specifically in coir because of its properties (locks onto, at a molecular level, Ca and Mg).

okay, first of all: thanks for the input, it's really appreciated

you misread: I germinated the seeds and cultivated them in coco coir. I thought it was the right thing as it was (allegedly) without any fertilizers. the coir was terrible because the seedlings/plants suffered from yellow leaves and two of them just fell over and snuffed it. turned out the coir was all salty ... but after that I repotted them into soil, and they recovered and grew within a week

I started with coco simply because it was available. I switched back to soil because things didn't look so good and soil's the medium I have the most experience with. noob experience that is ... like I said: this is my first 'proper' grow, everything else was just bag seed grown on the balcony, hit or miss. worked for me, but I decided to knock it up a notch.

okay, I got that with the foliar feeding. it's the first time I actually tried this, and I did it because one of the grow guides I found on here suggested this. it's history now.

I'm not really big into all the chemical details. not because I don't care, but because I admittedly don't understand all of it (I'm an arts / humanities scholar ... pretty much because any applied science career was out of the question, seeing how much I sucked at chemistry/physic/math in school). However: what I know I picked up from reading ... a lot. problem is that you get 5 different opinions by reading through 3 different books, and in the end I can either pick up more books ... or try what actually works and what doesn't.

so my next step will be getting a proper ph-meter and re-think my nutes solution & feeding schedule. thanks

@944s2: thanks. I think I can rule that one out. 1st the issue appeared before I started bringing rain water into this, second the rain water is 100% fresh, collected and put to use right after the rain or not more than 3 days later (I live in a high precipitation area).

I missed that, you're right.

If those roots have hit soil then treat it as a soil grow. That means forget about the additional issues with Ca & Mg that are presented with coir, as well as those pH parameters.

Stop feeding, give water only. Do your best to make sure it's within the proper soil pH range, and observe for 1-2 weeks.

Now, if the leaf margin yellowing progresses during this time then you know 100% there's a Mg-, and this is very easily corrected in one of two ways, including the foliar application of MgSO4 that Big Brotha mentioned, I use 1/4tsp/gal water + surfactant. Again, IF it's a Mg- that treatment will correct the yellowing very quickly.

I hear you on the chemistry, I'm terrible at maths and really prefer to grow by feel. For this reason I do my best to learn as much as I can about the different signals plants give us. I have a long way to go, of course, but I'm workin' on it!

Anyway, I'm also a cheap bitch, because even if I'm terrible at math I'm great with money, so I don't use hydro store nutes for the most part, and so I've never used BioBizz, can't speak to it specifically. I have used stuff like Floranova Bloom in coir and perlite hempy tubs, but not in soil. My soil's always organic, soil food web methods, and I prefer to grow outdoors.

In any event, it's still possible to use any nutrient you wish, but I feel it's best to start by at least halving the schedules provided by the manufacturer, and I usually take it down to 1/8th the scheduled dose, then work my way up. I've also spent some time playing around using separate elements, so I've learned the difference between Ca- and Mg- and how to work with them. You clearly have the beginning of a Mg-, as I mentioned, possibly a P-, doubtful a N-. And the bit about the pH.

I like rainwater, use it a lot. If you suspect it's causing a problem, eliminate it. If you suspect the tap, eliminate that. I find frogs living in my collection barrels, so I figure it won't harm my plants at all. I'm on a well and my water is pretty hard by both general and carbonate measures, so that makes rainwater even more appealing.

Nute lock. In soil just flush really well and when renuting take it slow. Make them ask for more food rather than over feed and have to flush and starve.

okay, so I gave it a good flush until the runoff was pretty much clear
let's see what happens now

just curious: does flushing cause symptoms of overwatering? my pots have real good drainage (custom made, yay) and they all rest on what's essentially trays you use to put your wet shoes on, so the water can run off unhindered and even air can reach the soil from below. but I just ran nearly 1.5 times the gallons the pot can hold through that soil, so I'm kinda afraid of root troubles with that much water involved ...

does flushing cause symptoms of overwatering?

It can if the root ball/mass hasn't dried out.

Not if it is able to run off to waste. Just make sure that your medium is dry enough down by roots before watering again though. You arent trying to over water it in flushing. just trying to clear out all the nutrients up in the medium. Once that is done the water drains still. Just go lightly on nutes after. Make it tell you it is hungry if it is a finnicky strain. A lot of sativas prefer lower amounts of nutrients. At least ones I have experienced.

Hans-von-Dampf said:

okay, so I gave it a good flush until the runoff was pretty much clear
let's see what happens now

just curious: does flushing cause symptoms of overwatering? my pots have real good drainage (custom made, yay) and they all rest on what's essentially trays you use to put your wet shoes on, so the water can run off unhindered and even air can reach the soil from below. but I just ran nearly 1.5 times the gallons the pot can hold through that soil, so I'm kinda afraid of root troubles with that much water involved ...

Click to expand...

I personally wouldn't have done that since they're in soil, I feel they were nowhere needing such a drastic measure (yet? perhaps on their way). But it's too late now. The short answer is yes.

I use those same trays, too. Oddly shaped, yet perfect in so many other ways, ya know?

Anyway, as the others have pointed out, let her get a bit dried out (not completely, no need for that, then proceed from there.

oh well ... it's done and as of now, it doesn't seem to have make it worse. but that's all I can say for now. the water drained super-god and the soil turned from wet to most and back to humid within 2 days. that shouldn't be the problem (on the upside the water kept the RH in the tent at a steady 75% for for quite some time, so I didn't have to run the humidifier)

it's going to be warm & dry the next few days, so I'll just sit tight and wait until they really ask for another watering. then they'll get water only

also, a PH-meter is on its way

when do you think I could possibly take some clones to determine the sexes?
my plants back in the days usually had pre-flowers, but these are in week 7 now and nothing to see so far. but since I want install the screen for scrogging them soon, I really wanna know which ones to keep and which ones to move out there

okay, so far the healthy plants decided to grow like hell while the poor sickly looking one pretty much stayed the same. the condition didn't worsen (which it did before, this has stopped) and I hope it's going back to vegging soon.

I wanna take those clones this weekend. Would it be calling for trouble if I take clones no matter what or should I wait how this pans out?

Hans, none of those plants looked "sickly" to me, so I'm going to say go ahead and take some clones.

oh okay, SeaMaiden, thank you
so making clones this weekend it is

I'll keep you posted

and happy towel day to all ya hitchhikers

plants look healthy, eary on they present themselves like that, everything is fine

okay, took the clones ... nothing much to say about it now.

after watering with water only (rainwater + tap water, mixed to get PH 6.8 - 7) for the last 2 weeks, leaves started to look really pale from the bottom up. that does mean they're hungry, right? I fed them 1/2 the dosage yesterday and the green appears to come back. Nitrogen I guess ...

I foliar-fed some epsom salts just like you suggested and it looks much better now, thank you.

BUT there are some dark spots (3-5mm) on two or three of the paler leaves, yellow-ish with a darker centre (I'll post a pic later). What's that supposed to tell me? is it just another deficiency that came with the plain water?

Possibly, especially if there are pale leaves at the bottom, again hungry would be the suggestion. The MgSO4 helping to green them back up suggests that everything needs to be increased.

okay, here's what I'm talking about

something I should be worried about? like I said: water is PH 6.8 - 7, runoff was around 6.2 - 6.4 (3 pots, each had a different reading of course)

leaves seem to turn back green, I started tying the plants around my SCROG-net, binding away some of the bigger fan leaves to let light down to the lower growths. some of them are on their way up already