NEED HELP. 5 Weeks into Flower. Leaves turning yellow/purple

Judo90

Member
im currently growing a cotton candy kush strain. First time grow. I am using a 600w LED Light. Using nutrients from my local hydroponic store (see nutrients in pics). It is dutch nutrients line. I am growing in a 3 gal pot using ocean farm soil. My lights are about 12-14” from canopy of plant.

I have been making sure to get run off each time i water and feed. I ph my water to 6-6.5 everytime. And run off is around 6.8. My EC levels foing in are 1.1 and my run off is around 1.8-2.1. I water them everyother day typically. I use a water, water, feed schedule.

Im currently in my 5th week of flower (day 35). I am noticing that on my one plant the leaves around the tops are turning purple around the edges. And starting to become a faint yellowing. I have researched and found so many possibilities but i dont want to start messing around too much. ANY HELP WOULD BE GREATLY APPRECIATED!
 

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undercovergrow

Well-Known Member
how about put some pictures up under regular lighting? it could very well be over-watering at this point. usually soil doesn't need to worry about PH etc. so you might be loving them too much. keep in mind you are growing an annual plant, so at this point don't chase problems. alter your watering schedule and see how the one girl responds as the other looks fine. cannabis likes a wet/dry cycle.
 

Judo90

Member
how about put some pictures up under regular lighting? it could very well be over-watering at this point. usually soil doesn't need to worry about PH etc. so you might be loving them too much. keep in mind you are growing an annual plant, so at this point don't chase problems. alter your watering schedule and see how the one girl responds as the other looks fine. cannabis likes a wet/dry cycle.
I will definatly get a picture under regular light for you guys to help better. I do only water when the soil is very dry. Which is typically every 2 or 3 days. The pot is very light.

But i will try to let them go a bit longer without as im sure it wont hurt.

You dont think i should be changing to much of what i am doing at this stage?

Thanks for your help. I really do appreciate it.
 

ShLUbY

Well-Known Member
12-14" for an LED is really close. not sure what brand you are using, but typically they should be 18-24" from the canopy.

all the other parameters seem fine to me...
 

undercovergrow

Well-Known Member
I will definatly get a picture under regular light for you guys to help better. I do only water when the soil is very dry. Which is typically every 2 or 3 days. The pot is very light.

But i will try to let them go a bit longer without as im sure it wont hurt.

You dont think i should be changing to much of what i am doing at this stage?

Thanks for your help. I really do appreciate it.
we would need to see pictures of the girls under regular lighting - if you're letting the pot get light before you water it then don't change that at this point. your LED might be too close but for instructions regarding LEDs, you will need to wait for someone who has experience growing under them.
 

Judo90

Member
12-14" for an LED is really close. not sure what brand you are using, but typically they should be 18-24" from the canopy.

all the other parameters seem fine to me...
I am also thinking this could be my issue. 14” is what the manufacturer recommends. Im using a 600w viparspectar light.

Other thing is its only happening to the one plant. Other girl has no signs of this.

Right now i have ZERO space left in my tent to get the light any higher. ANY RECOMMENDATIONS on what i could do?

Thanks for helping.
 

Judo90

Member
we would need to see pictures of the girls under regular lighting - if you're letting the pot get light before you water it then don't change that at this point. your LED might be too close but for instructions regarding LEDs, you will need to wait for someone who has experience growing under them.
Thanks alot
 

CannaBruh

Well-Known Member
Sorry. You would be surprised if it were the loghting? Or wouldn’t be surprised?
I don't suspect it's lighting, I'm leaning towards them being fed too hot or too often as your runoff ec is pretty dang hot. They look burnt from nutes not by lights imo.

All in all they don't look horrible, seen many a harvest having gone waaaay further south. Good on you for seeking out corrective action, let's see what some others say.
 

ShLUbY

Well-Known Member
another thing it looks like to me is K deficiency.... but typically you would see that in the oldest growth first and not the newest, because K is mobile in plants. that's why i'm leaning towards light burn.

can you dim the light any? try switching the plants around, and move the unaffected one to the spot where the affected one is. maybe there is a hot spot in the light itself.

something else I just thought of... if your runoff is 6.8, and going in it's 6-6.5, your soil may be over buffered and it's not remaining acidic enough. pH being too neutral or slightly alkaline would affect the newest growth first for things like Iron, which is important in the synthesis of the chlorophyll molecule itself. so the fact that its going in at 6-6.5 and coming out higher than its going in, should indicated that your pH in the soil is actually higher than your reading because you have to account for some neutralization happening with the acidic watering.

I really don't like using runoff to determine medium pH. You'd be much better off with a decent soil pH probe. Bluelab makes a nice unit, though it's a little pricy at ~145$. but well worth it. when i purchased mine, it helped me dial in the pH of my medium BIG TIME.
 

Judo90

Member
I agree with the light bleaching. Try turning your plants every now and then as well as raising the light.
another thing it looks like to me is K deficiency.... but typically you would see that in the oldest growth first and not the newest, because K is mobile in plants. that's why i'm leaning towards light burn.

can you dim the light any? try switching the plants around, and move the unaffected one to the spot where the affected one is. maybe there is a hot spot in the light itself.

something else I just thought of... if your runoff is 6.8, and going in it's 6-6.5, your soil may be over buffered and it's not remaining acidic enough. pH being too neutral or slightly alkaline would affect the newest growth first for things like Iron, which is important in the synthesis of the chlorophyll molecule itself. so the fact that its going in at 6-6.5 and coming out higher than its going in, should indicated that your pH in the soil is actually higher than your reading because you have to account for some neutralization happening with the acidic watering.

I really don't like using runoff to determine medium pH. You'd be much better off with a decent soil pH probe. Bluelab makes a nice unit, though it's a little pricy at ~145$. but well worth it. when i purchased mine, it helped me dial in the pH of my medium BIG TIME.
So you think i should put in lower ph levels?
 

CannaBruh

Well-Known Member
To me it looks as if some of the tops aren't even affected, how would leaves which appear affected as a result of light burn when they are at some distance greater than leaves above them which appear in great shape?

Last time you calibrated your meter? Or are you using drops? Does your base water ph appear as normal indicating your meter is acting appropriately?

What are your daytime canopy temps?

IME you can run LEDs on the plants/touching as long as temps are in check.
 

Judo90

Member
To me it looks as if some of the tops aren't even affected, how would leaves which appear affected as a result of light burn when they are at some distance greater than leaves above them which appear in great shape?

Last time you calibrated your meter? Or are you using drops? Does your base water ph appear as normal indicating your meter is acting appropriately?

What are your daytime canopy temps?

IME you can run LEDs on the plants/touching as long as temps are in check.
I totally agree which is why i originally ruled out light burn.

I use a ph tester pen. It is calibrated properly as my tap water is tesing correct around 300.

Day time temps are around 21-24• celcius. When light are off i drop to a low of 18.5 celcius. I have a fan blowing up from the bottom. And one blowing across the canopy. Also using a exhaust fan and filter. So plenty of air circulating.
 
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