Yellow leafs with brown dots =/

[AutoBuddy]

Hi everyone.
I seem to have a little problem with my ladies and i cant seem to find out what it is, my thoughts on it is that it might be Co2 poisoning, to much heat or to low humidity or maybe Ph problems, just because i have had problems with keeping them on a regular level. But since i dont know whitch of them to fix i cant help them.
So if there is anyone that recognise the problem (see pics) i would be happy to get some help. =)
My setup; 400 w HPS, a small "flower" lamp, fan, Co2 (Sugar jeast and water), fertilizer is Hesi Bloom complex, the growing medium is 25*25*30 cm.
And the ladies are almost exactly 7 weeks from sprout in soil, and are Nirvana Northern Lights Fem Auto.
Pic 1-3 is nr1 pic 4-6 is nr2 and the others is just on my growing space.
I think that i should add that i have 4 ladies more, but they all seem to be fine.
Thanks

 

[Muddy]

It's probably the start of a cal/mag deficiency. But it could be caused by your pH being off. Before you do anything you must make sure your pH is correct. If you haven't done so already, check the pH of your run off and let us know what it is.

 

[ripster]

Before we go any farther, flush that plant with water only, ph'ed at 6.20...If you don't, it's gonna get worse real fast..........

 

[AutoBuddy]

Thx for the reply Muddy.
I´ve checked my Ph of the water to the plants its a little high 7-7.5, and i dont have anything to messure the soil Ph, but i know whwn i bought it it said on the bag 6-6.5 so my thoughts was that it would even up. But then its likely that my high ph locks out cal/mag ?? And how do i fix this, any good tips ?? =)

 

[AutoBuddy]

Thx Ripster !
I only have one question on that, is ok to flush with tap water, im thinking about the fluor levels and such if i dont have it sitting out 24h? =)

 

[Muddy]

You'll need to check the pH of the run off from your pots. Flush them with some water balanced to a pH of 6.2 as Ripster suggester. When it starts running out the bottom of the pot, capture some of it and check it's pH. I'm betting it will be too high, thus causing a nutrient lockout.

Even though the soil bag said that was the pH, you really need to check it yourself to verify. What kind of soil is it?

 

[AutoBuddy]

Ok, will do that and get back with a value, sorry for being such a noob and ask thousands of questions but do anyone have a good easy tip to lower the Ph of water?
The soil im using is an environment friendly with no extra chemicals or such, and it has sand in it for good drainage.

 

[Hugo]

There are many ways to achieve that. You can either buy it from your grow shop, or you can use something from your kitchen like lime or white vinegar.

Cheers

 

[Muddy]

No worries, we're here to help and glad to do so. Distilled white vinegar will work as a temporary fix. You should get a bottle of pH Down. Just a few drops will lower it to where it needs to be.

Sand in your mix is a no no for growing weed. It tends to compact the soil too much and can prevent good oxygen exchange to the roots. You are much better off using perlite for drainage. what else is in that soil mix?

Ok, will do that and get back with a value, sorry for being such a noob and ask thousands of questions but do anyone have a good easy tip to lower the Ph of water?
The soil im using is an environment friendly with no extra chemicals or such, and it has sand in it for good drainage.

 

[AutoBuddy]

I have just flushed the ladies with fresh water with Ph around 6.2, i dont have the best ph testing equipment so its kind of hard to be precis, but the first one i checked the first water coming out and that was ~5 and the last water that came out was ~6.5 the second one was ~5 in the first water coming out and the last was ~6.
All this seems like a mystery to me because the water i have been using is leaning more towards 7 i ph, and when i flushed it with the ~6.2 the water coming pout was more negative then the water i put in.

And the soil im using, i dont think that it was anything else mixed in just soil and sand, but lesson learned no more sand to the ladies. =)

One more thing i think i should add, my fertilizer do have something called ph correction, i dont know if thats good or bad in my case, but it did sound good when i bought it.