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 shrogrow
Stranger
Registered: 09/03/09
Posts: 54
Last seen: 14 years, 9 months
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 Mg or N deficiency? *update* Hole in leafs :panic: 
#290488 - 10/02/09 09:22 AM (15 years, 1 month ago) |
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1. Are you growing from seed or clones?
seed
2. How old are your plants?
35 days
3. How tall are your plants?
Hard to say, been LSTed.
4. What size containers are they planted in?
11 liters
5. What is your soil mix?
This soil contains the following nutrients (g/m^3):
Nitrogen: 210
P: 105
K: 225
Ca: 2000
Mg: 250
S: 120
B: 0.7
Cu: 2.8
Fe: 5.9
Mn: 3.6
Mo: 3.3
Zn: 1.6
Mixed with 15% perlit
6. How often do you water and what type of water do you use?
Once every 4th day, last two waterings has been with one day interval though.
7. What is the pH of your water?
Around 6.8
8. What kind of fertilizer do you use and what is its NPK ratio?
Used fertilizer once, a couple of days ago when I first noticed the problem. Thought it was a N deficiency, so I started using a fertilizer with the following amount of nutrients per 100ml: 7.1g N, 1.5g P, 5.9g K, 0.2g Mg, 35mg Fe, 10mg Mn, 10mg B, 5mg Cu, 2mg Zn and 1mg Mo.
9. Do you foliar feed or spray your plants with anything?
no
10. What kind of lights do you use and how many watts combined? (HPS, MH, fluorescent, halogen, incandescent "plant lights")
two CFL, 125W 6500K and 125W 2700K
11. How close are your lights to the plants?
About 5cm
12. What size is your grow space in square feet?
55x55 cm (3.25 square feet)
13. What is the temperature and humidity in your grow space?
During night: 23-25 degrees C
During day: 28-30 degrees C
Humidity: 40-55%
14. What is the pH of the soil?
Run off water is between 6 and 7.
15. Have you noticed any insect activity in your grow space?
no
16. How much experience do you have growing?
First time growing cannabis. Been growing various capsicums and tomatoes for a couple of years though
Reason I'm worried is that the couple of leafs that show the symptoms (oldest leafs) has progressed to the worse and not better after feeding with hight N fertilizer. So if someone could please help me determine what's wrong with the poor baby I would be very grateful!
*update*
Scroll down for update
Edited by shrogrow (10/03/09 01:10 AM)
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 Tcrib
Stranger
Registered: 09/03/09
Posts: 125
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Re: Mg or N deficiency? [Re: shrogrow]
#290516 - 10/02/09 11:11 AM (15 years, 1 month ago) |
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Can you post a picture of your whole plant?
Also, I will recommend a soiless mixture for your next try.
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shrogrow
Stranger
Registered: 09/03/09
Posts: 54
Last seen: 14 years, 9 months
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Re: Mg or N deficiency? [Re: Tcrib]
#290522 - 10/02/09 11:28 AM (15 years, 1 month ago) |
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Here (s)he is in full glory! 
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Tcrib
Stranger
Registered: 09/03/09
Posts: 125
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Re: Mg or N deficiency? [Re: shrogrow]
#290526 - 10/02/09 11:40 AM (15 years, 1 month ago) |
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Considering its only affecting those two leaves I wouldn't touch anything, the rest of the plant looks fine. If it continues to spread then I would consider adjusting one of the nutes or checking the pH.
What is the pH of the soil? Clean water has a pH of around 7.0 but obviously when its added to the soil/nutes the pH will either go up or down considerably in some cases.
The leaves are a little light in color and this leads me to think the pH may be too low keeping the Nitrogen from entering the plant. Check the soil pH. You can get some strips for nothing at walmart or something.
Also, another thing you want to look at is you see some of the leaves edges curling up? This is a sign of under watering. I would worry about the pH first though.
Aside from those couple of things the plant actually looks fine at this point.
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shrogrow
Stranger
Registered: 09/03/09
Posts: 54
Last seen: 14 years, 9 months
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Re: Mg or N deficiency? [Re: shrogrow]
#290539 - 10/02/09 12:14 PM (15 years, 1 month ago) |
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I've got a pH meter. My clean water has a pH of 8.0-8.3, and it goes down to 6.1 with nutrients added. So I corrected that with some bicarbonate to 6.9. The run off water came out at 6.8 (and 6.5 in my other plant). The run off water was a bit too acidic last time I check though, so it may very well be what you say - too low pH locking up nitrogen.
Might as well take the time to ask about watering while we're at it At the moment I'm watering my plants with 1 liter each. They are in 11 liter pots (with 10 liters of soil each). Should I give them more water each time I water, or is this fine? I normally get about 1dl of run off water.
Thanks a lot for your help Tcrib. I'll keep an eye out for more discolorations.
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Tcrib
Stranger
Registered: 09/03/09
Posts: 125
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Re: Mg or N deficiency? [Re: shrogrow]
#290711 - 10/02/09 05:28 PM (15 years, 1 month ago) |
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The rule of thumb I use is mainly from someones book but I can't remember which one 
Anyway, I water enough to allow about 10 percent drainoff. To ensure you are watering evenly, because it doesn't look like the water is getting distrubted evenly, I like to pull the soil about an inch away from the pots all the way around them...Then slowly pour water evenly in the little trench that you built around the pot. Lift up the pot see how much water is draining out.
Which leads me to another thing be sure to have adequate drainage for your pots. I've heard many different rules applied here but personally I recommend at least 4 1/4 inch holes on a pot the size you are working with...I have, I think don't hold me to this I'm not staring at the pots right now, 6 1/4 inch holes on a 5 gallon bucket which is about twice the size of what you are using.
You don't want too much water escaping but you don't want water standing on the bottom of your pots either.
By the way your pH sounds fine I either missed something or am retarded...Probably both.
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shrogrow
Stranger
Registered: 09/03/09
Posts: 54
Last seen: 14 years, 9 months
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Re: Mg or N deficiency? [Re: Tcrib]
#290923 - 10/03/09 01:08 AM (15 years, 1 month ago) |
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Okay, sounds like I've got the watering part right then. I try to distribute it evenly. I've attached a rubber tube to my watering can so that I can easily reach around the plant. I'll try your trench-technique next time I'm positive I've got adequate drainage, I even put a layer of leca in the bottom of the pots to avoid water buildups.
Anyways. I noticed the following when I checked my plants today:
 
 
This is my other plant, the one that is not showing the yellowing of leafs. I really don't like the looks of this. Parasites? I've carefully inspected the leafs, but I can't see anything remotely close to a parasite, unless they're _extremely_ small. I could only find this on these two leaf clusters. They're fairly new leafs. I removed them from the plant to be on the safe side. Anyone have any idea of what this might be?
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moogles
Registered: 09/23/09
Posts: 196
Last seen: 13 years, 2 months
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Re: Mg or N deficiency? [Re: shrogrow]
#291065 - 10/03/09 10:03 AM (15 years, 1 month ago) |
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No clue about those holes, might have something
munching on the leaves. In your most recent picture
it looks like you are indeed having an issue with Mg.
The twisting and turning of the leaves is a common
side effect of MG deficiency.
It does not look THAT BAD, and it might even be something entirely different. But, this is where I would start.
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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Re: Mg or N deficiency? [Re: moogles]
#292049 - 10/04/09 10:37 PM (15 years, 1 month ago) |
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Light burn can cause holes in leaves, this is also suggested by the turned up leaf margins in your first pic (a symptom of heat and nutrient buildup). Try moving your lights back a bit and lowering your cab temps.
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shrogrow
Stranger
Registered: 09/03/09
Posts: 54
Last seen: 14 years, 9 months
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Re: Mg or N deficiency? [Re: Dr. Penguin]
#292240 - 10/05/09 09:53 AM (15 years, 1 month ago) |
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Light burn makes a lot of sense. It was one of the upper leafs which had the holes. And as you said, many leafs also had turned up leaf margins. I checked pH of run off water yesterday and it came out 6.1 and 6.3, so I've probably had some nutrient deficiencies too. I think I've manage to correct it now though, they look a bit happier. I've also moved my lights back a bit. Thanks for all the help 
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