SunnDogg

Hello all,

I’ve been a silent member for almost 2 years now and first want to thank all of you in advance for the time and energy you put into this site. You continue to provide a wealth of information that allows novices such as me to achieve independence and the satisfaction of growing our own. I’ve read countless journals, threads and the grow guides here along with 2 plus years of HT mags and Jorge’s guide for reference. I’m exactly 4 weeks into my first grow (good bag seed) and have found myself in a situation where I need some sage advice. Below I’ve listed my setup and all that I could think off to help isolate the issue. My digi just took a dump so I’ll borrow one tomorrow and update w/ pic’s so I apologize. Thanks in advance for any and all help you can provide.

Setup:
Grow space w/in Cabinet – 32”W x 24”D x 48”H (under lamp)
400w HPS/MH Conv. Lamp w/ Remote Ballast and Vented Hood
Ultreflect reflective material on all side walls
2- 6x14 Vents w/ 115CFM Bathroom fan for air exchange
Small desk fan for additional cooling & stem strength building
Rapitest H2O & pH Meter
Temp Range: 80 degrees +/- 10 degrees
Humidity: 35-45%

Soil/Nutes:
Organic Potting soil from Earle May w/ no pre-ferts mixed w/ 1/3 perilite ~7pH
Fox Farms Grow Big, Tiger Bloom & Big Bloom
Aged Tap or Bottled water w/ ~7pH

-Germ'd 6 seeds in water 3-Jan
-Placed all 6 in damp paper towel 4-Jan
-All 6 germen and placed in 8” pots w/ said soil 5-Jan – All 6 sprouted
-Lost 2 due to const. accident and nosy cat on the 12th
-Germ'd 2 more 13-Jan (Soil 15th)

Watering schedule is based on H2O meter registering within the 1 of 4 range or pot feeling light. I typically wait another ½ day or so from when I feel like I should be watering to make sure that I don’t over water. I’ve started nuting every other feed w/ FF recommended schedule (starting w/ their second week formula at full strength) on group A on day 16. I originally germ'd these 4 with CFL’s while I waited for my HID to arrive and they stretched like no other. Group B seems to be off to a much better start under the MH. I typically feed them liberally until all soil is saturated and water drains through the bottom and let them drain so that no standing water sits in their trays.

Here’s my problem. Within the last week or so I’ve noticed some tannish-brown discoloration on several of the lower leaves that seems to be migrating up to some of the newer leaves and some are also curling up. Several leafs also have small yellow and/or brown spots which I thought might be burns from water magnifying under the light, but no more after I’ve been more careful when watering. The lamp has always been at least 12+ inches from the plant so I don’t believe the light has burned them either. My best guess is that the curling could be from root rot or over watering, but doubtful due to the metering and drainage they seem to have. They may almost be root bound, but some of the smaller ones exhibit the same problems so I’ve ruled that out for most if not all of them. I’m left with nute burn, poor pH or both. I’ve followed FF schedule to their recommendations and based on them being organic and by feedback I’ve read here I've used their full recommended dosage. My pH meter (Rapitest probe) is not the best, but it seems to hover right at or just below 7 at all times. I hope to re-pot fairly soon and may try to wait until I have acces to FF potting soil in another week or two and maybe sooner with my current soil based on your recommendations. Any ideas would be greatly appreciated. Thanks again for your help.

penguin

Great description of your setup and problems.

I would try to keep the temp below 85 and get the RH up into the 50's, and back off on the nutes.

High temps + low RH + full strength nutes = nute burn.

Usually the first symptom of overwatering is droop.

I'd pick a single water source for consistency. How are you measuring your water pH, and do you have any idea on the mineral content?

Given that your soil pH is a bit on the high side, I'd water with pH a bit on the low side.

I'd give them 3 waterings with just plain pH adjusted water, and then reintroduce nutes at 1/2 strength.

Good luck!

SunnDogg

Thanks for the feedback Penguin.

I recently added a humidifier to the area where the grow is at which brought it up considerably and I also add a couple of mason jars of ice that I change twice daily as they melt which also seems to help. Given the time of year and my location it's drier than a bone and in the summer I'll struggle dealing with the exact opposite.

I'm not sure of the mineral content and could use some advice on the best way to figuring that out. I could also use a little guidance on what/where I should look for a different pH tester as my probe meter doesn't appear to be too accurate and I've read that most who are in the know wouldn't even bother with them. From here on out I will most likely use just city tap water that I've let sit for a couple of days to dechlorinate.

AzAdvocate413

If yer getting ready to transplant, I can see why those bottom leaves are turning, the pot the plant is in has probably been filled with roots.
I've seen this my my own garden, the combination of a touch too much fertilizer, mixed with the possily high water pH and tight quarters could be the prob.
As far as testing the water a 10$ pool pH test kit will get you the readings you need for the water. pH adjust up and Down for aquariums can be used to adjust the water pH.
I have to say a good soil test kit from RapidTest or other name brands will give you accurate readings on the 4 basic soil properties. Given an accurate chemical soil test a pH meter could then be "calibrated" from the readings of the test kit.

__________________
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penguin

If you're on a municipal water supply in the US you can probably get a water analysis from the water department. If not, you can get your water tested by a water testing lab, google "water testing laboratory mycityname" to get some leads. You could also get a TDS or EC meter that would give you an idea of total mineral content, but not composition.

I wouldn't worry too much about soil pH unless you do a lot of flushing. A decent quality commercial potting soil should be pH balanced and buffered.

For testing the pH of liquids, you can use pH test strips (limited range or low precision), swimming pool/spa pH test kits (limited range), a horticultural pH test kit (available at hydro and gardening stores), or a pH meter.

What's your ambient temperature compared to your cab temp? You may need more exhaust capacity than your bathroom fan is giving you.

Can you move the humidifier inside the cab? Hanging wet/wicking towels, or using a wet gravel tray (large surface area) inside the cab can also help greatly with humidity.

Oppyeahuknowme

Correct me if I'm wrong, but doesn't plants absorb the acidity from the soil. So, if you started with soil of ~7 and watered the plants with water of ~7 then I'd have to start looking at the ph of the soil.

It might be a bit basic in nature and while not damaging to a great extent it doesn't present the optimum environment. Though it would be a tough arguement to wager that all the ills of your plants would be heaved upon a little basic soil. I'f the soil is ~7 or basic I'd give'em a dose of ole' Migraclegro 30-10-10...by now I figure evreryone thinks I own stock in the company

OPP

SunnDogg

Below are pics of the setup and the plants that are most affected. I last nuted the initial 4 on the 27th w/ Fox Farms grow big at 15mL/Gallon and watered them this past Sunday the 31st. I will try to pick up another soil pH tester today as a double-check, but my probe meter always reads in the 6.9 to 7 range consistently.

Thanks again for your input.

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Oppyeahuknowme

There's nothing wrong with your plants that I can see. That color is normal wear and tear. Still I'd give'em a little shot of 30-10-10 to get the ph down to 6.3-6.5.

penguin

Good pics, nice cab. They are not in terrible shape.

Appearance is consistent with previous diagnosis. Less heat, more RH, and a little lighter on the nutes should do it. If you can't do that, then maybe supplement CO2.

juanmarijuana

I would say a flush wouldnt hurt...If that doesnt help than it is obvious ph prob...