Is This a Nute Problem?

I’m a newb grower, and thought I’d done my homework before starting my grow, but I’ve run into a problem that doesn’t seem to appear in any of my grow guides. I’ve also been through the ‘Pests and Probs’ here as well, but don’t see anything quite like this, although some seem similar. First, I’d best let you know the setup and conditions. (I apologize in advance for being so wordy, but I can’t ask ya for a diagnosis if I don’t give ya the info)

Unfortunately, I’m an apartment dweller, which has effectively limited me to shelf growing (or Sea of Green if you prefer, although not using clones), easily hidden and kept from sight by any maintenance workers or visitors. The grow area itself is pretty limited, foil lined on all 6 sides with the dull side out, about 13” deep, and 30” wide by 25” tall. This only gives a bit more than 2 ft sq. of floor space, and a volume of ~5.5 cu ft. (Yes, I realize how miniscule this is, but I was planning to grow these to only 12” to 18” tall, or train if necessary.) Due to both the limited space and my inexperience, there are only 2 plants, one for each square foot. (I was hoping this would also limit the smell, but it will also cut the chances for females.) Air circulation is good, temps vary a bit from 75-85 F, humidity varies from 50-80%(max). They are illuminated at 30W/sq ft (don’t know the lumens, sorry), by 3 flouro tubes, 2 red/warm spectrum and 1 blue spectrum, kept a constant 2-3” from the plant tops. Currently the light regimen is 24/0. I wound up using Miracle Grow enriched potting mix (21-7-14), which is kept damp but NOT wet, and seems to drain well. (I know, everyone says MG sucks, but they have a pretty effective lock on the market around here, and I don't want to prep my own soil.) Volume of the pots is slightly more than 1 gal. The pH level is a hair over 6.5 (electronically measured), and watering is done every 2 or 3 days (pH 7, distilled, non-foliar), no fertilizing being done yet since the soil came enriched and the plants are only about 2 ½ weeks old. The plants themselves are obviously an Indica variety of some sort, but are simply bag seed, and have just hit the 5”-6” mark. These have been grown in place after germination, and never transplanted. They REALLY love that blue light, and the newest growth at the top is lush, healthy and green, and has recently picked up growing speed. Internode lengths are ~1/4”, and they are beginning the 7th leaf sets. However, here is the problem…finally! The first 3 leaf sets are sagging with a downward cupped, wilted looking appearance, progressively worse the older/lower the set is. The stem, leaves and veins maintain a healthy looking green color overall, but some tiny brownish/whitish spots have appeared in the middle of the affected leaves, about the size of a pencil point. Leaf edges are clean, and the main stem is not discolored. The largest spot is on one of the first set of the leaves, about 1/8” diameter, and looks brown in the middle. The leaves are not dry or crumbly to the touch, just very limp. Close inspection shows no apparent parasites or fungal problems, and the area (and myself) are kept clean. The wilted appearance is now beginning to make its way upwards to the 4th leaf set, starting at the tips, but no spots (yet, I fear). The references I’m using lead me to think this could possibly be a magnesium or potassium deficiency, but this doesn’t quite fit the profile for either problem. (Maybe a shading problem? The topmost leaves are pretty big…Bad pH meter also a possibility…) Any advice that you experienced growers have would be GREATLY appreciated! (Sorry, no pics…no digital camera )

 

Well, I see that although responses have been underwhelming, a few eyes have still passed over this thread. So I figured I'd post just what I've found and done over the past few days, with the hope that maybe I can save somebody else some aggravation and heartache. Quick FYI: they are much improved now, and the prognosis is good.
First thing was a new pH meter, to make sure there was no nute lock from an imbalance. The old one WAS giving the correct readings(*whew*), but the new one is much more responsive. Then a few hours each day, over a couple of days, first re-reading Ed R's Grower's Handbook and then Greg G's Grow Bible cover to cover again. (OK, to be honest, I kinda glossed over the history/hash making/etc. this time around...) It was Ed's book that made something click initially, although if I hadn't blinded myself regarding my soil I'd have saved myself some headaches. The dirt issue had come around to bite me right onna ass. I'd convinced myself that the enriched soil that I started with wouldn't need ferts for a while, and the prob was either a secondary or micronute that was low or missing. (Theoretically, it still could be...time will tell.) But in the flowering section, a blurb about migrating N made a lil' light bulb go off in my pointy head. (HID, of course, LOL.) No wonder the symptoms weren't a good match, and the tops still looked great. Duh. After I stopped kicking myself, decided to take a risk and made a batch of food at 50% (Peter's 20-20-20, +micros since I thought it might also be a manganese prob). I figured I'd give it 2 or 3 days to improve, and apply an epsom salts mix if it didn't, thinking it could yet be a magnesium problem, even tho the leaves weren't "praying". Didn't even hafta wait a day: overnight the improvement was definate, but some of the lowest leaves are probably beyond hope. Just part of the learning process, but man, there sure is an awful lot of info to assimilate. Guess that's why it's called a learning curve .

 

Hey HT! Good to see ya got it worked out! I was onna the guys who was lookin . I woulda replied but Im pretty ignorant in the ways of soil. Not that I wanna be but I just havnt had the time to figure it out. Onna these days when I get everything runnin smooth the way I like it Id like to learn some Dirt. Overgrow.com's got threads on cf and flouro growing that might interest ya. Id help ya if I could myself but I realy dont know mutch bout what yer doin. -see I started a fyew years ago with a real perticular system and some prety perticular nutes with a perticular method and lerned it and little elce. I could show ya how to duplicate my system if ya want ! Ya dont need much more than a 9 x 5 aeria and bout 1500 watts. It aint much really but it packs on the buds ! -Lemme know! Blessins on ya Brudda!

 

Heya Lumpy-good to hear from ya again, bro. Didn't mean to sound like I was complaining, just hoping I can keep someone else from making the same mistakes I made. Don't mind tellin' ya, the problem had me sweatin' there a while. Yeah, I picked thru OG as well, and all the mounds of info I've downloaded from everywhere else, too. Took my trusty manuals to set me straight. I'd dearly love a 9x5 area to use like you, instead of this shoe box I've got, but I guess you gotta go with what ya have . I appreciate the input! Happy growin', dude .