P deficiency?

oscar de grouch

oscar de grouch

Active Member
Hey all! I seem to have a deficiency that looks like P to me. I've been all over google and several forums trying to figure this out. This happens to ALL of my plants regardless of strain and typically begins around the 2-3 weeks veg. This one happens to be ICED grapefruit. I give them their first feeding at 3 weeks @ 1/2 strength. Does it look like P def and if so, what would you suggest I do to fix it?

Some basic stats:

  • 12/12 entire grow under 4' 4 bulb HO T5 with a couple CFLs for side lighting.
  • 4x2x4 grow tent
  • 165cfm 4" inline fan w/ carbon filter
  • 3:1 Fox Farm Happy Frog and perlite
  • Fox Farm Trio nutes per schedule (1/2 strength first two feedings) and I do the :water, water, nutes:
  • RO water with 1-2tsp CalMg+
  • pH 6.7-7.0
  • Temps: 76F lights on 73F lihts off

Pdef.png
 
Bakatare666

Bakatare666

Well-Known Member
I don't think your PH is the problem^^^^^^^^^^^
However, does this start before or after you give first feeding?
Remember, the damaged leaves will not heal, but new growth should be OK, and damage should not continue to existing leaves if you have it fixed.PHRANGECHART_zpsddd4a5c5.gifView attachment 2490348
 
oscar de grouch

oscar de grouch

Active Member
pH is after feeding. I've seen that chart everywhere. I'm just not seeing pics like the one I posted. I have some ph up but I haven't used any. The water with or w/o nutes is usually at about 6.5. I just ordered some ph down. Should I lower it a tad?
 
Kite High

Kite High

Well-Known Member
looks more like the leaves were burned by the feed water imo

ie the cotyledons look fine


leaf tips must have gotten immersed when you poured the feed water in

it is very rare to have ph issues in soil/soiless
 
oscar de grouch

oscar de grouch

Active Member
Doubt it. I'm very careful not to do that. And like I said, it happens to ALL of them at this stage. And it starts at the tip and moves it's way up the leaf. This is actually at 3 days from when I first noticed the tips. Thanks for your input though.
 
Kite High

Kite High

Well-Known Member
happens to the best of us....all the other leaves appear fine including the cotys so I highly doubt it is any deficiency
 
oscar de grouch

oscar de grouch

Active Member
Kite High said:
happens to the best of us....all the other leaves appear fine including the cotys so I highly doubt it is any deficiency
Click to expand...
This has happend to 8 consecutive plants. It starts at the older leaves and once those are dead the next set of older leaves die. It moves from the very tips of the oldest leaves and progresses up the plant. I'm stumped.
 
LogicTime

LogicTime

Active Member
It sounds like a deficiency lol, funny enough I think I just read something about that in one of the mod threads I'll take a look again
 
LogicTime

LogicTime

Active Member

  • Zinc (Zn): Zinc does a little of everything, helps in plant size production of leaves, stalks, stems branches... Essential component in enzymes and growth hormones. its key in the formation of chlorophyll. Plants that have a healthy amount of zinc are more resistant to drought.

    Abundance: this is rare. it can cuase wilting and death in extreme cases. but usually, this wont happen.

    Deficiency: Spotting, bleaching of spots between veins (commonly confused with iron/mag def). Usually appears on older leaves first. It will affect the tips of growing points on the plants. Small crops due to zinc def is common. Pale/greyish leaves will be apparent (check for a nice shine to the leaves, if they lack some luster, they might lack zinc!)​




 
S

sm00thslp

Member
If not Zinc, maybe the soil temp is slightly too cool and slightly too moist at the same time. Dampening off. Maybe too compact causing the two as well. Make sure your watering with room temp water, and not cold, cold water.
 
G

GK1

Active Member
So, is the pH 6.0 or 6.5 when you feed it? If your just ordering pH up now and you're using RO water and you say its 6.5 after nute add.....its not adding up. RO water is for this discussion, essentially ionically void and tough to pH without adding some sort of nute or acid/base. Typically when you add the nutes to RO you see a substantial drop in pH. If you are seeing 6.5 after nute adds in RO my guess is you have a bad meter or are getting a bad reading somehow. I've seen it drop as low as 4.9 IME. The first thing I would do is verify my pH readings.....if you are adding super low feed water then its pretty easy to see how things are being locked up. The reason I asked about how you're getting to ph 6.0 is because adding alkaline reagents to your nute mix can be tricky if you have no experience and doing it incorrectly will cause cal to lock up. Regardless of final pH, adding alkaline reagents incorrectly will cause problems. Peace.
 
oscar de grouch

oscar de grouch

Active Member
GK1 said:
So, is the pH 6.0 or 6.5 when you feed it? If your just ordering pH up now and you're using RO water and you say its 6.5 after nute add.....its not adding up. RO water is for this discussion, essentially ionically void and tough to pH without adding some sort of nute or acid/base. Typically when you add the nutes to RO you see a substantial drop in pH. If you are seeing 6.5 after nute adds in RO my guess is you have a bad meter or are getting a bad reading somehow. I've seen it drop as low as 4.9 IME. The first thing I would do is verify my pH readings.....if you are adding super low feed water then its pretty easy to see how things are being locked up. The reason I asked about how you're getting to ph 6.0 is because adding alkaline reagents to your nute mix can be tricky if you have no experience and doing it incorrectly will cause cal to lock up. Regardless of final pH, adding alkaline reagents incorrectly will cause problems. Peace.
Click to expand...
Yeh, I thought my meter could be part of the prob. I'm using http://cdn2.bigcommerce.com/server300/838f0/products/817/images/1885/1815__03044.1334192511.1280.1280.jpg
 
G

GK1

Active Member
oscar de grouch said:
Yeh, I thought my meter could be part of the prob. I'm using http://cdn2.bigcommerce.com/server300/838f0/products/817/images/1885/1815__03044.1334192511.1280.1280.jpg
Click to expand...

Ok brother, is that what you use? Ouch. Do you test the water pH ever? If not, we know the problem. Add to that the inherent low pH of ProMix and it ain't rocket science. How big is your grow? Is it worth investing in a decent meter? Why are you using RO? Finding a program for you is easy...just need a little info. Peace
 
oscar de grouch

oscar de grouch

Active Member
Thats what I use to test the soil, which is fox farm happy frog, not promix. I just got one of those cheapy yellow digi ph pens for the water. I use RO because my tap water is so full of crap this time of year you can't see through it, and I just found the ph is 9.3. The RO ph is 8.2 and drops to 5.5 after adding 1tsp CalMg+/gal. I adjusted it with pH up to 6.5 and tested the run-off (no nutes, just CalMg+), which was 6.4. I dunno, my other babies just got fed for the first time last week and I went organic with them. I'm using the General Organics line and it looks like they are loooovin it.
 
You must log in or register to reply here.
Top