Lime green and curled new growth on auto

Here's the set up 4 autos in a 3x3 under the mars hydro tsw2000 average temp is 78 and humidity is around 60-65%. I'm about to be on week 3 and everything has been going well until about a day or two ago and I noticed the new growth on one of my big bud autos has been coming in with bright green almost yellow on the edges of the leaves and this morning I checked and now they are curling down slightly and has a brown spot on one of the tips. I'm using great lakes water only living soil so all I've been doing is watering when dry with PH at 6.5. And the light is around 22" above the tops of plants. Not sure what's going on or how to fix it or if there is anything to worry about at all lol. Any advice would be greatly appreciated thanks in advance.

Looks like magnesium deficiency. Yellowing leaves with green veins. I only know from what I've read, I've never had this issue personally. Try adding some CalMag and see where it takes you.

Since this appears to be affecting only new growth at the top of the plant and not in the middle or lower part of the plant, I think this is an immobile nutrient problem, specifically either Zinc or Iron.

Often, Zinc or Iron deficiencies are caused by improper pH of the nutrient mix being fed. Are you being consistent?

Bigdave78 said:

Here's the set up 4 autos in a 3x3 under the mars hydro tsw2000 average temp is 78 and humidity is around 60-65%. I'm about to be on week 3 and everything has been going well until about a day or two ago and I noticed the new growth on one of my big bud autos has been coming in with bright green almost yellow on the edges of the leaves and this morning I checked and now they are curling down slightly and has a brown spot on one of the tips. I'm using great lakes water only living soil so all I've been doing is watering when dry with PH at 6.5. And the light is around 22" above the tops of plants. Not sure what's going on or how to fix it or if there is anything to worry about at all lol. Any advice would be greatly appreciated thanks in advance.View attachment 4595985

Click to expand...

Just out of curiosity, what’s the NPK ratios of that soil? I know most fert ready soils are solid in terms of Nitrogen, and can be a little hot for seeds, but once in flower you might wanna supplement some P and K into your feedings. I use amendments and sometimes I see what you see, but it usually dissipates on its own over time.

Dontjudgeme said:

Just out of curiosity, what’s the NPK ratios of that soil? I know most fert ready soils are solid in terms of Nitrogen, and can be a little hot for seeds, but once in flower you might wanna supplement some P and K into your feedings. I use amendments and sometimes I see what you see, but it usually dissipates on its own over time.

Click to expand...

I honestly couldn't tell you what the NPK is the bag doesn't tell you and I've looked online with no results lol. I have been looking at maybe top dressing to help give it a boost through flower but after seeing this I'm not sure if the medium is too hot or if it's missing something

spek9 said:

Since this appears to be affecting only new growth at the top of the plant and not in the middle or lower part of the plant, I think this is an immobile nutrient problem, specifically either Zinc or Iron.

Often, Zinc or Iron deficiencies are caused by improper pH of the nutrient mix being fed. Are you being consistent?

Click to expand...

I'm just watering when dry with PH at 6.6 to 6.8 zero nutes have been added. Was told since it's a living water only soil that k wouldn't have to add anything but starting to think different lol

spek9 said:

Since this appears to be affecting only new growth at the top of the plant and not in the middle or lower part of the plant, I think this is an immobile nutrient problem, specifically either Zinc or Iron.

Often, Zinc or Iron deficiencies are caused by improper pH of the nutrient mix being fed. Are you being consistent?

Click to expand...

I'm just watering when dry with PH at 6.6 to 6.8 zero nutes have been added. Was told since it's a living water only soil that k wouldn't have to add anything but starting to think different lol.

Bigdave78 said:

I'm just watering when dry with PH at 6.6 to 6.8 zero nutes have been added. Was told since it's a living water only soil that k wouldn't have to add anything but starting to think different lol.

Click to expand...

You definitely will have to add something P and K related once you hit flower. Most soils with ferts in them don’t offer enough P and K during flower. Even top dressing won’t cut it. I use amendments, but they are specific to the stage of growing that I’m in, and I still have to supplement kelp and guano to keep up with the demand in flower. I would imagine you have to do the same.

Dontjudgeme said:

You definitely will have to add something P and K related once you hit flower. Most soils with ferts in them don’t offer enough P and K during flower. Even top dressing won’t cut it. I use amendments, but they are specific to the stage of growing that I’m in, and I still have to supplement kelp and guano to keep up with the demand in flower. I would imagine you have to do the same.

Click to expand...

Alright thanks for the info. How long into flower should I add something I've noticed today on 2 of my girls we are showing pistils should I add right away or give it some time. They are still pretty young today is day 19 since they sprouted. Sorry for asking so many questions

Bigdave78 said:

Alright thanks for the info. How long into flower should I add something I've noticed today on 2 of my girls we are showing pistils should I add right away or give it some time. They are still pretty young today is day 19 since they sprouted. Sorry for asking so many questions

Click to expand...

Thats what everyone is here for, ask away. But usually you have about 1 week after the flip before the girls go into full flower. After that I would provide the P and K slowly until you get to full strength.

If you have the ability to check the pH of your soil; this is where I'd start. Good luck.

CannaCountry said:

If you have the ability to check the pH of your soil; this is where I'd start. Good luck.

Click to expand...

Can I do that by checking PH of the run off next time I water

She looks thirsty... soil looks very dry how much each time you water?
what ppm water are you feeding in
I would wonder whats in the soil, possibly high npk
plant is pretty young to be having crazy deficiencies, many wont show up for 6-10 weeks.
It has some symptoms of a zinc deficiency.
The marginal & interveinal chlorosis and rossetting leaves.

when I think its a micro nutrient disorder I will foliar spray with a mix of cal/mag - Zinc sulfate - magnesium sulfate.

if you really want to know if its zinc get some zinc sulfate and foliar spray the plant and root feed it some in the next 2 waterings, and watch for recovery... this is pretty common in the first weeks of flower but can happen at anytime, usually phosphorus.


Cal / mag

Zinc sulfate
https://www.amazon.ca/Zinc-Sulfate-Monohydrate-35-5-Pound/dp/B00T6I1SKS/ref=asc_df_B00T6I1SKS/?tag=googleshopc0c-20&linkCode=df0&hvadid=293004032873&hvpos=&hvnetw=g&hvrand=1469595066706683552&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9000892&hvtargid=pla-319576760131&psc=1

Magnesium sulfate (Epsom salt)

yes get a runoff ppm/ph reading to get an idea of whats happening.

Overwatering - high ph -low temps all slow zinc absorption and make it less available to the plant
excess phosphorus can lockout zinc which is common in flower when you start tossing the PK boosters on them.
A ratio of 10 / 1 phosphorus/zinc is suggested
high Bicarbonates in tapwater lock up zinc also, this can occur after flushing with tapwater.

Thanks for the awesome advice. Starting to make sense now and that pic is exactly what she looked like before the curling started. Gonna give the zinc and phosphorus a try for sure

Just checked the run off ph and it's at 6.1 the other 3 girls where 6.3 and they are looking healthy and happy just started LST with them 2 days ago. Just makes me wonder if the medium in her pot was a little off, which would be strange since all for are in DNC water only soil and have gotten the same treatment. I admit I was probably under watering them in fear of over watering being a first timer that was my biggest fear I guess lol, and the temp does tend to drop to the mid to low 60's when the light is off which im sure didnt help much. But this is why I'm doing this I love learning new things and experimenting...and of course I love marijuana lol.

Bigdave78 said:

Can I do that by checking PH of the run off next time I water

Click to expand...

Your run off wasn't too bad...and I would guess it mirrors your soil to a point, so it doesn't look like the culprit.

Alrighty update on my sick big bud auto. Since I posted all I've been able to do is give her a couple good drinks with tap water PH of 6.4 her run off was 6.1-6.2. I'm noticing now that the yellowing has faded and she's starting to look good and green. But I've noticed a lot more brown rusty spots and crusty edges on some of the bigger leaves. Newer growth still drooping and not very happy. Finally got a day from work to get to the store to hopefully get something to help her. Kingkush 4200 mentioned a possible zinc issue and recommended a foilar spray of cal mag and zinc sulfate with magnesium sulfate. Just curious if thats still the route I should take since the leaves are getting their color back? Any advice would be greatly appreciated.

don't spray her right now man they are burning and a foliar will not help with this issue. it must be something in your medium that is toasting them if all you are doing is watering with tap water.

are you are you adding ph down or something?

kingkush4200 said:

don't spray her right now man they are burning and a foliar will not help with this issue. it must be something in your medium that is toasting them if all you are doing is watering with tap water.

are you are you adding ph down or something?

Click to expand...

I was thinking it's something in the medium as well just funny how my other girls aren't showing any negitave signs that i can tell. And yes I've been using PH down since my tsp water is well above 8. Could the PH down be hurting her?

This is what I'm using for medium