Light burn?

I need some help please. The leaves have light green spots all over them. They are more noticeable on older 3-tipped leaves. I think it might be light burn, I raised the light a bit.

I topped it yesterday, the spots were there before that.

Strain: Green poison fast
Age: Almost 3 weeks
Light strength: ~20 DLI, now ~17 DLI
Nutrients: non, soil from grow shop
Watering: every 2-3 days when the top 2cm feels dry.

I see no burn. I currently have a girl that was to close to the light and she purpled out. I'll try to get a pic

puudub said:

I need some help please. The leaves have light green spots all over them. They are more noticeable on older 3-tipped leaves. I think it might be light burn, I raised the light a bit.

I topped it yesterday, the spots were there before that.

Strain: Green poison fast
Age: Almost 3 weeks
Light strength: ~20 DLI, now ~17 DLI
Nutrients: non, soil from grow shop
Watering: every 2-3 days when the top 2cm feels dry.

View attachment 5194822

Click to expand...

Not light burn IMO. Looks like it needs Magnesium. Epsom salt, maybe a teaspoon dissolved in a gallon of water. Water when you normally would, the normal amount you would use with the Epsom salt water, and you will know in a few days if it greens up.

Thanks! It sure does look like a magnesium deficiency. I have these TA (GHE) DualPart nutrients. The bloom part, which I should add 1mg/L contains 3% magnesium oxide. Will it be enough? Or should I just go out and buy a kilo of magnesium sulfate?

puudub said:

Thanks! It sure does look like a magnesium deficiency. I have these TA (GHE) DualPart nutrients. The bloom part, which I should add 1mg/L contains 3% magnesium oxide. Will it be enough? Or should I just go out and buy a kilo of magnesium sulfate?

Click to expand...

Magnesium is the most common deficiency in early veg.
If it was me, I'd go with the magnesium sulfate and see if it greens up. If it's a mg deficiency it will improve in just a few days, and you will know for sure what it was. Other fertilizers might have mg but you may end up giving the plant something it doesn't need yet. A good % of both soil growers and hydroponic growers have magnesium sulfate in their arsenal.

What is that “ grow shop “ medium ?

Hard to believe you would get early issues from it.
Mag issues can be corrected with epsom / tap water use ( municipal water has it already ) or combination of both. Epsom can be Foliar sprayed for faster absorption.

Budzbuddha said:

What is that “ grow shop “ medium ?

Hard to believe you would get early issues from it.
Mag issues can be corrected with epsom / tap water use ( municipal water has it already ) or combination of both. Epsom can be Foliar sprayed for faster absorption.

Click to expand...

I find it common and often mis diagnosed. I feel it happens in soil not from a lack of Mg in the soil. It's more an issue of the roots not yet established enough to deliver enough Mg for the plant's needs in the early stages of veg especially if it's a strain that is slow to root.

I am using tap water, it's around 200ppm according to municipal charts. I let it sit for a day to let the chlorine evaporate. I made a patch of it in the beginning and pH corrected it to 6.5. Been feeding this the whole time. Now when I checked the pH it was around 8. There's one of my mistakes, I need to check the pH more often. Not sure how it could rise on its own, but it did...

The soil is from my local grow shop, they mix it themselves. It contains:
40% peat
40% compost
10% vermiculate
10% perlite

Also they gave me a little baggie of mycorrhiza to spread around the planting area. At first the soil was really clumping together. I should've let it dry out a bit I suppose. Today I lifted the plant off from soil and aerated the soil as much as I could, I think it's much better now. Of course I couldn't aerate the area directly at the roots.

As far as the nutrients go, I got impatient and fed it half of the recommended dose of TA DualPart. Now I got a bottle of CalMag from a friend. I'll check in couple of days if the pH correction, aeration and TA nutrients did the job. If not then I'll add a low dose of CalMag.

I really appreciate you guys helping out the noobs!

Edit: A picture of the current situation

Mix apparently has no buffering. No lime / oyster shell / etc.
There are much more complete mixes available on the retail end.

She's so cute, I think she looks fine. I'm not sure I'd feed it anything just yet. Then, the way I roll, I'd top dress it with some FFHF or FFOF, simply because that's what I use and I have some on-hand. I add that to mine at about week 4 - 5. Scratch the surface and water it in. But, that's just me. Good luck, I think she looks good.

Budzbuddha said:

Mix apparently has no buffering. No lime / oyster shell / etc.
There are much more complete mixes available on the retail end.

Click to expand...

Would this be a better option?

Other than that one I don't have any cannabis specific soils available. I'm not really a fan of my current soil. It tends to clump together and it has big hard pieces in it. Wood or peat.

Cynister said:

She's so cute, I think she looks fine. I'm not sure I'd feed it anything just yet. Then, the way I roll, I'd top dress it with some FFHF or FFOF, simply because that's what I use and I have some on-hand. I add that to mine at about week 4 - 5. Scratch the surface and water it in. But, that's just me. Good luck, I think she looks good.

Click to expand...

The 3-tipped leaves developed small burn spots on the smaller leaves... It's hard to spot from the picture, I added a new picture. But I agree that I shouldn't need to feed it anything at the moment.

that thing is burnt crispy id start with better genetics must be a flawed seed

Mos Eisley said:

that thing is burnt crispy id start with better genetics must be a flawed seed

Click to expand...

I hope it's not quite that bad. Even if she is needy by genetics then I'll learn to grow faster I suppose.

This is her now. I never managed to cure the deficiencies. New growth looks fine, then it gets yellow between the veins, then spotty and then looking real bad. Must be a mobile nutrient, right?

I water it 3L at the time and wait until soil feels dry, pH 6.0-6.3. Usually something like every 4 days I think. On the day I water it always looks sad, the next day it springs to life. Pictures are taken a day after watering. Pictures look greener than in real life - phone camera doing tricks.

I have tried feeding it cal-mag at 1/3 - 1/2 the dose. I'm not 100% sure if it made any difference. And a few times GHE DualPart fertilizer. At 1/3 dose it seemed ok, at 1/2 dose it burnt the tips.

I have a friend who also grows the same genetics in same soil and his growth is much healthier and faster. I don't want to throw it out of the door as a 'bad seed', although it feels likely. Maybe there's still something I'm doing wrong or should try?

Are you checking ph of water runoff after it hits the soil?

Northstar831 said:

Are you checking ph of water runoff after it hits the soil?

Click to expand...

No i haven't. I check pH of the water before. Should it be in the same range 6.0-6.5? And if it's off then I should water with pH that's off from my usual? For example: I get runoff pH of 5.5, then I should water at 7, until runoff pH is in range? I haven't tested it before, because runoff water always looks yellowish and I use drops to get the reading with color. I just thought it might not be very accurate this way.

I believe you are correct on that, runoff should be a little higher, also the roots might drowning in muddy clumps of soil all week, I had the same issues with promix soil and literally ripped my plants out of the soil, rinsed the roots off and went back to my hydroponic days and they are loving it

Thanks! Hydro would be too hardcore for me right now... I'll check the pH when I do the next watering - in 3-4 days.

Also my plant is super bushy, I believe it's due to genetics and high amounts of light?

I tested runoff and it came in at 4 pH...

I flushed the pot quite heavily with tap water 7-7.5 pH.

In the end I fed it with 1/3 dose at 6.0 pH, runoff was 6.5 pH. (it reversed?!?)

Will see in some time, if it made the difference.