Plants' lower leaves are turning yellow. Normal or sign of trouble?

My plants are about 35 days old and seem pretty healthy overall. They were showing some signs of stunted growth and when i check the roots it seemed like it was time to transplant them from 5quart pots to 12s.

My concern is the plants lower leaves. They are turning yellow and getting a dried crispy feeling to them. I have started to lightly spray the plants with a neem oil mix to ward against a possible mite problem and am now worried the new soil i added was not fully sterilized. If there is anything in the soil causing this yellowing what can i do to prevent my plants from further harm?

The new soil mix was a blend of hummus and manure soil with some perlite and vermiculite.



H=Answer if you grow hydro or aero
C=Answer if you grow coco
S=Answer if you grow traditional soil
L=Answer if you grow soilless other than coco (Promix, Hyponex, SunshineMix)
R=Answer if you grow in RockWool
T=Answer if you grow in HydroTon
D=Answer if you run any type of automatic drip system, including into soil or soilless
E= EVERYONE needs to answer lol!


E-indoor or outdoor- Indoor
E-soil, soilless, coco, aero, or hydroponic- Soil
E-specific medium- Miracle-gro Potting Mix(.21,.07,.14)
CSL-Soil type/brand- See above
HCL-Hydro/aero/soilless system type
SCL-Anything you have added to the soil
SCLR-Soil or slab runoff pH
E-Water source- Pur filtered tap water
E-Source water pH- Cheap ph meter i bought at lowes says about 7 but I am not sure if i can trust it.
HRT-Source water EC (if hydro)
E-Age of plant- about 35 days
E-Type of fertilizer-Peters All purpose plant food (.24,.8.16) I have only just started using fert. at a little less than .5 tbsp/gal. The instructions suggested 1tbsp/gal.
E-Rate of application (if hydro, this is your PPM number, preferably after each component is added)
E-Lighting source and distance from plant- 6x40watt florescent tubes in shop fixtures. About 2-3 inches from the top of the plants
E-Air temperature (both day and night if you are running a dark period) Around 80 degrees depending on what time of day it is and how intensely the sun is heating up my house.
HD-Reservoir temperature
E-Air % Relative humidity- I do not know yet
E-Lighting schedule- 24hrs
E-Type of ventilation your room has-a fan or two directed at the lights and partly at the plants.
TR-Did you pre-soak your media in pH corrected solution?

Those plants look very healthy to my untrained eyes. Really, a beautiful shade of dark green. Some yellowing of the very bottom leaves is natural. They are old and the new growth is using the ferts.

Totally normal, totally fine. Very nice work.
If those pots have built-in drain trays, remove them and stick something under the pots to prop them up. The tray+pot combo drains poorly and WILL cause problems later.

Thanks guys, its my first grow so everything is new :-p.

Good tip stinky, ill look for something to use. What would be large and sturdy enough to hold them up?

A couple pieces of broken brick under the pot should do it. Drainage is SUPER important, so do what you can.

Update

Ok so something is wrong and not due to ordinary plant growth.

Many more leaves are turning yellow, withering and dying.

I have no idea what is causing it but took several pictures. They leaves seem to get patches that are withering with the whole leaf eventually turning pale yellow then more brown before drooping and either becoming a soggy texture or crispy dry.

The only thing i can think of would be a problem with the soil used for thier transplant. None of the plants were showing any problems beforehand and all are now showing yellowing to getter of lesser degrees.

Please help! I don't want to lose all of my first grow.

as you get closer to flowering this will normally happen. Your plants look good. Just wait to you are late in flower you think that is bad...Looks like its about time to start some flower ferts too if you want.

You know, low leaves in the shade naturally wither and die off. Your plants look quite healthy, although they are still showing symptoms that they are root-bound. If you've just transplanted, that should improve shortly.
Think about this! As your plants grow in height, you raise the light. The distance from the light to the soil surface and lowest growth increases, to the point where the lowest growth is now getting insufficient light to thrive, and will be sloughed off by the plant, after the plant uses up whatever nutes it can (=mobile nutrients), causing the yellowing and necrosis. I see you are still under shop lights, which are great, but remember their penetration is limited and it may be time to switch to a HID lamp, or just learn to live with low leaf shedding.
Do you have plans to flower in the near future?

Alright, i am just worried because it does not seem to be just the bottom set of leaves that are showing yellowing and spotting along the leaves, some of the younger leaves seem to be suffering as well. I will be the first to admit I have no idea what normal wear is on a plant, it naturally looks bad to me when leaves on my plant that looks so lush and tasty a few days earlier get hard spots, yellow and wither :-p.


Yes I am thinking about flowering soon but there are a few things I would like to do first.
I ordered some black and white poly film yesterday and would like line my room with it before i switch to flowering so I have more control over and stray light that was not a concern during a continuous light cycle.
I am looking to order an hps system to flower under because i suspect flowering under flors, while Possible, will result in a much lower yield,several plant problems and more posts on here asking for help.
I also would like to take some clones from each of the plants before i set them into the flowering phase so i do not have the down time of starting from seeds again. I suppose I also need to determine the sex of the original five to get rid of any that may be males.

So those are the three things I would like to do before i go to 12/12. What would a good time table for me follow in order to take clones and start flowering? If I order my hps soon I should have it here sometime next week and be able to start, hopefully they will last a bit longer :).

Oh and one random questions regarding hps stinky. I know this is for plant problems and not lighting but would I be able to get away with purchasing a reflector without holes for ventilation?

I know it is better to have dedicated ventilation but it seems any reflectors that are cooling capable are much more expensive($50 more between the two systems i am thinking about) not to mention an actual inline fan costs quite a bit more than i expected.

Could i just have a fan blowing air up into the fixture to cool it?

I am looking at DIGITAL 600 watt HPS GROW LIGHT 600w SODIUM w BALLAST - eBay (item 180175343454 end time Jul-27-08 10:44:24 PDT) in case you wanted to get an idea of what I am considering.

Opinions before i purchase it for my babies?