Brown stains on older leaves

[sielm]

Hey there! I have this little Sweet Skunk Auto on a 1 liter pot filled with compo sana soil mix. She's 21 days old. I only fed her with pH 6.3 water, because the soil should have enough nutrients for a month at least. She's been developing stains on the first pair of 3-bladed leaves; the stains started on the center of the leaf (they don't affect the central nerves) and now cover more surface each day. The oldest, 1-bladed leaves are yellowing and I think that would be normal. But the 3-bladed have this strange stains that don't look like normal yellowing or ageing. Any ideas?



Thanks for your time!

 

[agito]

your pots are 2 small you would have to feed early
they may also need some mg also up your ph to 6.5 and test runoff

 

[sielm]

Thanks for the reply. Yep the pot is really small, this one was intended for the 32 oz competition, as well as for allowing me to cover all my grow surface with plants, fitting several pots in a small circular space. I see the leaves and I think they are quite dark green, and thus I did not feed anything yet. I am afraid to burn her. I have to try with pH 6.5 water and test the runoff. And also check my nutes and see if they carry mg. The water I use has the same ppm of Ca and Mg. Do these stains look like Mg def?

Thank you!

 

[agito]

it does look like mg or ph isuue could be wrong though. Yes they have enough n but they require more than just n in a cycle

 

[Muddy]

Need to know what your run off is. I suspect your pH is off and is causing the nutrients to be locked out.

 

[sielm]

I'll checking on that soon. I have not checked the runoff for this little plant yet, seeing as it was looking good (until now). I'll be back soon with the results, thanks all!

 

[sielm]

Well, I took the measures just a while ago. The water I use is tap water, which was aerated for 36 hours, and had pH 6.7 and ec 0.17 mS/cm. After watering her the runoff had pH 6.5 and ec 0.42 mS/cm. These values don't look bad to me, maybe the ec is too low? What do you think? According to a conversion table, that runoff value in ppm would be of about 200-300 ppm depending on the meter used. Is that too low of a value? Should I give her nutes? Mind you, these stains are only on 2 leaves, but I'm afraid it could extend to others too.

Thanks!

 

[agito]

if ppm is going up i would not feed
what your humidity

 

[sielm]

When you say "if ppm is going up" you mean when the runoff has higher ppm than the water?

About my humidity, it's currently around 55-60% when lights are on (20/4 schedule), and goes up to 70% when off.

I did not mention it before (I forgot, probably because of my medication ) after taking the measures I sprayed a couple of times with a very mild liquid guano dilution (NPK 4-5-6) which I believe also contains Mg. The stains do not look like they are going to heal, so I hope this does her some good.

Will check her back tomorrow, we'll see... thank you!

 

[agito]

yes when pm goes up theres to much feed i would hold off on feed until it stabilizes