Yellowing from tips and reduced growth

I'm having a bit of a problem and can't seem to sort it out based off the guides here. This is my second grow, I had a similar problem with the first in terms of yellowing but had no problems with reduced growth.

The large plant is Barneys Farm LSD and the small is a Siberian(Flowered straight from seed).
Ph is 6.3-6.5
soil, 3 gallon pot
Jacks blossom fertilizer as recommended for indoor plants.
Watering about half a gallon every three to four days, when the soil is completely dry at finger depth.
250 watt HPS, 12-14 inches away
Temp is ~81 (nothing I can do about that at the moment unfortunately)
Not sure if it makes a difference but I'm at 7500ft above sea level and have a RH that runs between 35-45.
Had a fungus gnat problem for a bit but got it under control with DE.

I'm having yellowing on the sugar leaves and fan leaves that seems to be starting at the tips and working it's way to the base. It's not isolated to top middle or bottom, pretty evenly spread. I thought it was a nitrogen deficiency but saw no improvement from adding any to waterings. Now I'm thinking over fertilization but wanted to make sure before I flushed. Any help is greatly appreciated.

Oh, and about 5 weeks into flowering, should be done around 25th.

It looks like nitrogen deficiency to me, but you said you thought that too and added some more nitrogen so I'm not sure. Did the problem get worse after you added more nitrogen or stay the same?

I want to say it got a bit worse. I did two waterings with my veg fertilizer and if nothing else saw no improvement.

What kinda water you using? Tap water can and does cause the probs you are seeing. If your water is hard it will lock out nutes and adding more is doing nothing for you

I am using tap water but it not hard by any stretch, it's city water and let the chlorine gas off before use . I planned on switching over to the zero water purifying system(unless there's another you suggest may be better) here shortly, I didn't realize it could cause such a problem.

I am using tap water but it not hard by any stretch, it's city water and let the chlorine gas off before use . I planned on switching over to the zero water purifying system(unless there's another you suggest may be better) here shortly, I didn't realize it could cause such a problem.

I assume you have a PPM tester:rolleyes: Check out the value of your water before anything is added to it. It is much more involved than just gassing it off. Minerals are what will kill your plants off. From the look of things you aren't going to be able to do much for the girls before they are done. Also are you checking PH on the runoff? I would almost be willing to bet the soil you are using is somewhat acid and you would have to add dolomite lime and set the water and nutes going in higher to raise the runoff.

That Zero Water system "will" work but I think it is a major pain in the ass:cool: I use the RO water available at WalMart. The Culligan dispenser is it. Got your own jugs it is .37 a gal where I am:D I am going thru about 10-12 gals a week and this is before I have my outdoor going yet

If ya get a min ya may wanna check out my grow in my sig:smoke:

Edited by blakeshouse, 09 May 2012 - 06:48 PM.

Thanks, a lot. I've been checking my runoff PH periodically and getting just over 6 with meter and strips. I'm going to check out that RO system, sounds like it will handle the job better.

Thanks, a lot. I've been checking my runoff PH periodically and getting just over 6 with meter and strips. I'm going to check out that RO system, sounds like it will handle the job better.

Other stores in your area should have the drinking water dispensers too. You can buy jugs at the location for a 1.00 or less and then just refill em.

Try raising the PH of your water to 7 and see what the runoff is then. Like I said there is little you can do for those so close to the end but I am sure you will see major improvement with your next go:D