What's wrong with my leaves

[Indica2013]

Can somebody help me please I'm on my second grow so new to growing.
I have 5 big Buddha cheese plants from seed I grow in compost, (John innes)
1 of the cheese is really bad all 3 leaves in the first picture are from the same plant. i use HESI products and grow under a 600watt HPS lamp,I have looked for hours
On ends trying to pinpoint the problem but most cases start with the tips of the leaves
My problem seems to start in the middle of the leaves some dull grey patches have appeared
The leaves are really brittle this seems to have started on the lower leaves and worked its way up
It also seems to start with little rusty looking spots as seen on the second picture
The second picture is pure power plant this seems to be spreading around the grow room
Although I have a critical mass which does not seem to be effected I have looked into ph problems,
But have seen a lot of info saying not to test ph in soil, I've spent hours all week trying to pinpoint this problem
Everywhere says something different could a be bad genetics or is it something I've done can somebody please help?

Big Buddha cheese (below)

Pure power plant (below)

 

[Happy Kitty]

Here's some information that should help. Keep posting those pictures and let us know how things are going.

Plant Abuse Chart

How to Grow Marijuana - Everything You Need to Know!

 

[Indica2013]

Thanks for the chart will keep posting cheers

 

[cannasensei]

looks like p and calcium or possibly stipling (bug bites) any pest lurking that uve seen? hows your ph?

 

[Indica2013]

No as I grow scrog I have to lie on my back and train under the screen I'm always looking for bugs/pests no sign of anything also As i grow scrog i cut away the undergrowth (I think where bugs like to live ?) I haven't tested the ph of soil as I have been told I don't need to test the ph in soil

 

[cannasensei]

Where they like depends on the critter. U sound vigilant so I suspect ud be aware if u had bugs.

If you are using tap water and or chemical nutrients u damn skippy better be checking Ph. I don't check everytime but once a week at least I am checking Ph from the tap soil and runoff (as well as the feed once mixed obviously) IMHO ur Ph is the difference between growing and pwning

 

[Indica2013]

I use hesi nutrients it's not organic i use tap water which I leave for 24 hours before watering I don't test ph as I've been told I don't need to test ph in soil also in my nutrient product booklet it says when cultivating plants in soil with HESI products there is no need to use any ph correctors

 

[cannasensei]

No offense. But I got a bottle that claims 20% yield gains and Ph perfect. They're full of shit IMO. Run sensitive with ur Ph at 8 or 4 ull see how necessary it is. This is all opinion and personal experience. I have nothing I can reference so take that as is. But Ph should never go unchecked especially if ur a beginner
Rule #1 when a problem arises check Ph.

 

[cannasensei]

Sorry rule #2 rule #1- loose lips sink ships tell noone.

 

[Indica2013]

No no offensive taken I'm glad you're replying to me I was going to test the ph but the person who introduced me to the world of growing doesn't test ph and doesn't have problems I am just worried I will do more harm than good trying to correct ph

 

[bandai]

Thank you for the chart

 

[KarlJay]

I leave my water out for several days, then the 1st thing I do when getting ready for watering is test PH. My tap water is ALWAYS too high. I need about 3/4 teaspoon of PH down acid each time.

I use the drops in the tube tester and it seem to be working pretty well.

IIRC ideal is PH 5.9

You can check my grow journal, link is in my signature.

All I'm using is GH Flora and I used nothing for several weeks because it's a soil grow. Then used CaliMagic because I thought I had an MG def problem. They are in a few weeks of flowering right now.

The grow was started mid Jan and they are now about 40" tall.

One other note: My last Grow Journal post has a link to the PPM Meter I got from Amazon for $16 ... You'll probably want one of these too. Online seems to be the best deals.

 

[WizHigh]

How many regular waterings do you do inbetween feedings? It could also be salt build up. And if your using tap water chlorine can cause the problem also.