Rusty patches on top leaves

[FONT=Arial, Helvetica, sans-serif]Hey I'm growing 6 fems of Real Gorilla Seeds Xodus#1. All of them have lots of brown rusty patches on the leaves of the top buds. Started around flowering. Looks to me like overfertilized but I didn't change anything. Is the uk cheese clone or are the descendants known for any nute sensitivity or other problems?
[/FONT][FONT=Arial, Helvetica, sans-serif] The other plants in the tent don't have this.[/FONT]
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NEED 4 SEED said:

[FONT=Arial, Helvetica, sans-serif]Hey I'm growing 6 fems of Real Gorilla Seeds Xodus#1. All of them have lots of brown rusty patches on the leaves of the top buds. Started around flowering. Looks to me like overfertilized but I didn't change anything. Is the uk cheese clone or are the descendants known for any nute sensitivity or other problems?
[/FONT][FONT=Arial, Helvetica, sans-serif] The other plants in the tent don't have this.[/FONT]
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Click to expand...

If it's not a lockout, it is calcium deficiency. Which makes sense - flowering is a time of a lot of growth, which required more non-mobile nutrients which becomepart of the cell - more cells, more non-mobile nutrients are needed.

Calcium
Silica
Sulphur
Trace Elements (iron, copper, zink, etc.)

I don't know what the medium is, environment (watering, temperature relative humidity, etc.).

So without that further information, I would say calcium deficiency.

Hey, the soil is an in-house brand of the local building center. It is their "light" brand meaning light-weight. It's not real compost, a lot of fibroid stuff in it. I actually took this one because I didn't want to carry the other heavy bags due to my back pain. I know its not ideal but I didn't have these spots before. Sadly there is no known fluid calcium product in my country. We only have dolomitic lime but I doubt this would make any effect fast enough when I dust the soil surface with it.

Ok the other factors: watering is ok, I don't overwater, I always check the pots. Humidity is unknown but we have spring and I have fresh air input (window). So it is not too dry or warm. At night the window is closed so they don't get cold. Light is a 315 W cmh lamp dimmed to 50-70% (which equals 157,5 W - 220,5 W) on 0,36 sqm (3,9sqft). The lamp is 30 cm (1 ft) above the canopy. Maybe you're right about the calcium and I should get back to my old habit of mixing in some dolime from the beginning.


Photos were taken on day 40 appr..

Somebody in another forum gave me a hint regarding ph. I measured the run off and it is at 6.0. I will take care of it with the next watering giving them some ph up.

NEED 4 SEED said:

Somebody in another forum gave me a hint regarding ph. I measured the run off and it is at 6.0. I will take care of it with the next watering giving them some ph up.

Click to expand...

With a pH runoff that low, I would look at lockout.

Usually a low pH doesn't lock out calcium. However a low pH could be a sign there are too many nutrients in the medium; or not enough oxygen in the medium.

The way I've solved over/underwatering and over/underfeeding, is that you feed from the top, and then rehydrate the medium by bottom watering with plain water. (I have pretty hard water with a high pH.)

Anyway, the next step is to check the EC/PPM of the runoff.

TanzanianMagic said:

With a pH runoff that low, I would look at lockout.

Usually a low pH doesn't lock out calcium. However a low pH could be a sign there are too many nutrients in the medium; or not enough oxygen in the medium.

The way I've solved over/underwatering and over/underfeeding, is that you feed from the top, and then rehydrate the medium by bottom watering with plain water. (I have pretty hard water with a high pH.)

Anyway, the next step is to check the EC/PPM of the runoff.

Click to expand...

We have very soft water with a ph of 6,5, maybe. I used litmus paper strips till now, which are a bit unprecise, but I do have pen tools for ph and ec since a few days. I will try to use them now. Lack of oxygen shouldn't be the problem. The soil is very fluffy and dries out good.

For today I removed the most damaged leaves.