Can anyone help identify this nute deficiency?

My soil is slightly alkaline, it was a little above 7 now I think its sitting just under it. That points to more of a zinc deficiency but I'm not really seeing white leaf tips. Iron deficiency would be my next guess but its hard to say. Yellowing only occurs in upper leaves between veins more toward the edge/tip of the leaf than the base of it.

Only leaves at top experience this, new leaves closer to the ground are fully green. Sorry for lack of focus on pictures but hopefully you can make it out. Any ideas would really be appreciated. This really is just a mild case too as most of the leaves are green and yellowing ones are only very slightly yellow. Still would like to get a handle on this though.

First off, they look ok to me, doubtful it's a zinc defeciency. More likely a minor ph issue.

But if you are going to worry, here's a couple of things to ponder before you fill-out the troubleshooting form: (available in my signature)

How are you testing your ph?
What's your water ph?
What brand and type of soil?
What kind of nutrients? (brand, dosages and schedule)

OMG its the worst case of ocgs i have evr seen you better do something about that







overly concerned grower syndrome:jointsmile:

Quote:

---

Originally Posted by Rusty Trichome

First off, they look ok to me, doubtful it's a zinc defeciency. More likely a minor ph issue.

But if you are going to worry, here's a couple of things to ponder before you fill-out the troubleshooting form: (available in my signature)

How are you testing your ph?
What's your water ph?
What brand and type of soil?
What kind of nutrients? (brand, dosages and schedule)

---

What is your experience level? (first timer, novice, experienced...)
First Timer

Your Equipment:
.1) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's)
Two 42 watt CFL's, 6800K, 6000 total lumen output

.2) Distance from tops?
Less Than an inch

.3) Reflector type? (cool tube set-up, bat wing, enclosed reflector, bare bulb...)
Built my own cool tube, taped aluminum foil on top of glass tube to almost double amount of light hitting plant.

.4) Is there a consistent fresh air supply?
Yes, 4" inline (output) fan running continuously for a roughly 1x1x3 foot box, passive intake holes throughout box.

.5) Do you have an exhaust fan and a circulation fan?
Exhaust fan only, at top of box

.6) What are the bulb wattages, kelvin ratings, and schedule?
See above, 20/4 schedule, 5th week vegetative.

Your medium:
.7) Specific brand and type of soil, (coco, peat based soilless...) and anything you've added to it. (vermiculite, perlite, worm castings...)
Local greenhouse organic soil mix, some water retaining substances are mixed in with it already and I added worm castings.

.8) Size of container.
4 gallon

Your nutrients and water:
.9) Source of water. (tap or filtered) What's it's ph?
Filtered tap water, allowed to sit out for over 24 hours before use. Ph Unknown.

10) Method of checking water ph. (ph pen, test strips, aquarium test kit...)
Soil pH test kit, take sample of soil, mix with water and pH powder and observe color. Bought a cheap pH monitor online yesterday.

11) Method of adjusting water ph. (phosphoric acid, white vinegar, hydrated lime, PH Up...)
Added a small amount of pH down last watering

12) Specific brand and N-P-K ratio for each bottle. List dosages (quantity per gallon) and current feeding schedule.
Green Lightnin', 12-4-6. I use less than half strength in almost all waterings which take place once soil becomes more dry than moist (every 4-5 days)

13) How often are you watering between feedings, and how much per watering?
Feedings are waterings for me. I add a little over a liter per watering.

14) Any additives or tea's? (Superthrive, CalMag, molasses, Mother's Earth...)
Nope

15) Are your ph levels stable, or do they fluctuate?
Was relatively stable at around 7 until I found that was too high, added a small amount of pH down last feeding/watering and pH is steady at around 6.8

16) What is your ingoing water's ph? ...your runoff ph?
Unknown

17) Do you foliar feed? If so, with what, how often, and at what time do you spray?
Nope

Your growroom:
18) Indoors or outdoors?
Indoors

19) What size of closet, room or hut?
Large rubbermaid container, a little over 1x1x3 feet, standing on its end.

20) What are the temps and humidity levels while lights are on? ...With lights off?
Temps are around 70 with lights either on or off.

21) Have you seen signs of insects in the growroom?
A few little bugs running around but not many at all.

Your strain:
22) What strain are you growing? (Indica dominate or Sativa dom?)
Hybrid, probably indica dominant. AK-48 from nirvana shop

23) From seeds or clones?
Seeds

24) Is this an autoflower strain?
Nope

Thanks man, appreciate any input you have on my situation.

My first impression was a bit of an overnute or slight ph problem. But after reading the form...2 litres of water per week in a 4 gallon pot is not nearly enough. My suggestion is to add two litres of nutrien solution (your half-strength mix) twice a week, and water twice a week with no nutes, with plain ph'd water.

A $7.00 aquarium ph test kit is usually much more accurate than the soil probes or test kits.

Quote:

---

Originally Posted by phatsesh101

OMG its the worst case of ocgs i have evr seen you better do something about that







overly concerned grower syndrome:jointsmile:

---

LMFAO...good one Phatesh...Plants looking good to me.