Help me nail this problem please!

For the last week or so one of my plants has been losing lower and middle fan leaves. I really don't think it's overfert since I've only fed them like twice in the last month. They are in MG organic potting mix with 50% perlite and topdressed with garden lime to stabilize and buffer pH.. but the mixture is 2 months old and the nutes probably consumed by now. I know these guys are rootbound as well since the males I culled during preflower were, and that was over a week ago.

These are going to be planted in the ground (I know, bad timing since it's 105+ outside) but I have no choice atm. But this isn't because they are outside, it started before then.

Note that this is only a problem on one plant and all 3 I have get the same treatment. The sativa pheno isn't showing any of the symptoms, one indica pheno has it BAD and the other indica pheno (looks just like the other) may have it very very mildly.

Do they need food in general? It could be Mg maybe. I don't know if it's a pH lockout or salt buildup. They were flushed like 2 weeks ago and fed once soon after. Soil pH is 7ish, my tap water is harder than a gangsta in a wife-beater. Comes out 8.4ish and ~400ppm. Lots of limescale in it. Perhaps too much Ca locking out Mg? I pH it down to 6.5ish before watering. Lack of all essential nutes? Help!

Could definately be nutrient lockout due to soil ph being too alkaline. I had the same problems when I first started then once I switched to distilled water the problem seemed to go away. My tapwater wasn't quite as high in ppm, but it was definately up there. The bottom half of my plant was always a battle to keep green, then once I switched over to distilled, gone. I quit using soils with ferts or time released nutes in them as well. I now just use a soil with no npk rating whatsoever, I give it nutes myself so I know exactly what it is getting at all times. The time released soil really wreaks havoc on soil PH. Good luck.

This stuff supposedly doesn't have time-release nutes. It's pretty mild .14 .7 .7, and was really acid out of the bag. I didn't know it at first and realized they had been growing in 5-5.5 pH soil for weeks until I added lime. Since then the pH has been stable. Took them a little while to adjust but they did. Just trying to figure out the best way to combat this now. They have been flushed since the last heavy feeding so I'm not sure what else to do.

They were dry this morning, so I gave them each a liter of tap water pH'd to 6.5 and they are drinking it up and perky, even in the hot direct sun. The first real sun they have seen since their first week of life.

u say they are rootbound i would make sure you let them dry out completely before watering. could be developing root rot

I let them dry fully before watering every time. (at least now I do.. i had the typical newbie overwatering episode way way early on, but it's nipped in the bud now!) They drink a lot, I give them about a liter every 3 days. By the 3rd day the pots are light and the soil is super dry. I watered them this morning for the first time in 3 days or so. They responded well to it. The buds are forming so well for this early stage, less than 3 full weeks since going 12/12 and it looks/smells so dank already!

i am battling a similar problem which i come to find out is my Ph is to acidic i just also added lime to resolve the problem im using MG soil .14 .14 .14 mixed with black earth topsoil the discoloring of the leaves look alot alike in those pics but a little different like a phosphorus deficiency maybe high Ph heres a couple links to take a look at pics to compare---->
http://www.420magazine.com/forums/problems-pests-disease-control/81275-cannabis-plant-pest-problem-solver-pictorial.html
http://www.icmag.com/ic/showthread.php?t=11688 <------more detailed

Yeah, I've been looking at that and a P def. is something I am considering. Once I transplant I will give them a feeding of GH bloom 0-5-4 at maybe 1/2 strength and see if that helps.

cool man i hope it pulls through good luck im subbed keep us posted!!

I just don't know what it could be.. other than maybe a huge pH lockout of mass nutrients. Several fan leaves have yellow, brown, grey and rust coloring. Looks like a combo of every deficiency!

I need to check my runoff pH and try to gauge the soils pH just to make sure but last time I did that it was consistently stable.

Well I did that.. the soil reads 7 or so all over the pot. The drain tray had a little water in from this morning, measured that pH at 7.1-7.2. Being hours old and warm I don't trust it. I'll get more reliable readings when I water them this evening. They drank all I gave them pretty quick.

But regardless, I know it should be closer to 6.5, and the water went in at that. The soil is right around 7 as is the runoff.. meaning it's pretty damn stable. I'm not saying pH lockout is impossible, but I think it's less likely than a deficiency.

i would wait til the leaves are actually starting to droop before you water, i would bet you have a poor root structure

They do have a slight droop to them!

Possibilities:
Root Bound~ How big is your pots? Pop'em out of the pot and check it!
Over watering~ Let'em dry out! Watering when the pot is lightweight!
Miracle Gro Organic Dirt~ Find another grow medium anything but with Miracle Gro on it!

I know they are rootbound. This was mentioned I think, if not.. oops. I am transplanting them this weekend though. They aren't overwatered. They get a liter every 2-3 days. The pots always feel light and the top of the soil is "too dry" (which is when I wait to water).

They were overwatered way back in veg stage, but not since. I'm not trying to change dirt.. I'm just trying to get them into the ground to finish. They only developed this problem a week or so ago. Which is why I believe it's a def. They have been producing thick buds ever since. I just want to know if it's a specific nute or general lack of food.. or a pH lockout.

The root structure, if it's anything like my culled males, is probably one giant ball in the pot with some perlite and dirt clinging to it.

The upper growth is perky and green. The buds, for 17 days of 12/12, are stinky and hairy and dense. I'm wondering if it's supporting this by eating the leaves. I would give them some food if I was sure.

Just going to dig some holes, line it with the leftovers of my original soil mix.. maybe amend with some topsoil I have laying around and drop them in. Give them a good good watering and hope for the best!

Here's some recent pics of the tops. This is the first time they've seen the sun since they germinated. It's 106 degrees. Got them in the shade for the rest of the afternoon.

The first one is a sativa pheno, hence the height and stretch.
The second is an indica pheno.
The third is also indica, but the one with the fan leave issues.

they are lookin nice still ULM!!

Other than one plant losing fan leaves, I agree!

The problem just sprang up quickly but it seems to have slowed since watering them with pH'd 6.5 this morning. Going to give them another good watering when I transplant and hope for the best.

I dont know what the problem is but first off i'd find some water that isn't so hard. 400ppm is a little too high for marijuana, i wonder how that breaks down into cal/mag/silica/sodium/iron/etc etc.

Personally i find water between 150-200ppm the recomended level with a 3:1 ratio of cal to mag at about 80ppm calcium to 25ppm magnesium at maximun levels. Use this as a guide and start eliminating the obvious problems. Peace

Well I'm not going to be able to change my water. I know it sucks. I can give them some distilled or R/O every now and then.. and I may do this when I transplant in fact but I've been using the same water since day 1 and the first couple of nodes on these plants lasted 6 weeks or more, despite my early turmoils. And some of those I only trimmed for airflow. This is a relatively sudden problem. Maybe there is some toxic buildup but none of the other plants have the problem.

The leaves are yellow, with copper and brown dead spots.

Mix half water with half r/o water to bring down ppm a bit and see how that goes. Peace

Get back to me when it gets worse and you have tried a few things, i'll take a guess then. Peace

Yeah, good plan.. I will supplement with a little epsom as well. I had to do that once early in the grow and that may be my problem now. I think my water is mostly Ca and low Mg.