Nismoskyline

The lack of iron is one of the more common nutrients associated with chlorosis. Manganese or zinc deficiencies in the plant will also cause chlorosis. The way to separate an iron deficiency from a zinc or manganese deficiency is to check what foliage turned chlorotic first. Iron chlorosis starts on the younger or terminal leaves and later works inward to the older leaves. However, manganese and zinc deficiencies develop on the inner or the older leaves first and then progress outward. Plants need iron for the formation of chlorophyll. Chlorophyll gives leaves their green color and is necessary for the plant to produce the food it needs for its own growth. Iron is also necessary for many enzyme functions that manage plant metabolism and respiration. Iron becomes more insoluble as the soil pH climbs above 6.5 to 6.7 (7.0 is neutral - below 7.0, the pH is acidic; above 7.0, the pH is alkaline). With most plants, iron can only be absorbed as a free ion (Fe++) when the pH is between 5.0 and 6.5.

I have two plants around 1 month old, or a little more. They are bagseed. Two differnt strains. They are growing in a medium sized pot, and are outside during the day. I used miracle grow soil that is made to not allow underwatering or overwatering. I bring them inside when it is dark and put them under my lights. The first plant is about 2" smaller than the second one. The other one is around 16" high. They have not been LST, cliped, toped, or anything like that. For some reason all the older leaves are turning yellow first, then dying off. The new leaves at the top, and the new leaves growing from the braches off the main stem are also health looking. Is this due to chlorosis? Maybe my soil is just a little bit above 6.5 pH, and the plant cannot absorbe iron? I have tested the soil with a cheap test kit. The color it showed looked exactly like 6.5 and I have not added any ferts that could change the pH.

outdoors

Nismosklyline-

I have read a lot on this site about miracle grow soil not offering the best growing medium for MJ. Perhaps you can do a search on Miracle Grow.... I'm sure there will be lots to read.
Is this the first time you've grown?
Can you take a picture of the plant?
Peace-
Outdoors

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Nismoskyline

This is my second grow. My first grow was just one plant. It had the same problem also but not close to as bad as these two plants are showing. And no I cant take a picture, sorry.

milsurp

I'm sorry I can't be of more (or maybe any!) help, but let's make sure we all have our terms correct here to start off with. Always good to be sure that everyone is on the same page, so to speak.

You asked if the yellowing was due to chlorosis - "Is this due to chlorosis?".

Chlorosis is a symptom - not a cause. It would be like asking "I have a cold - I wonder if my runny nose is causing it?".

I might not be qualified to give advice as I am no expert, but if it's not a pH or overfert or overwater or any other "obvious" issue, then I would look at giving a little fertilizer (we're looking for N specifically), and would also have to consider a magnesium defficiency.

I'll leave it to the pros to guide you towards Cal-Mag or a similar product (calcium, magnesium, nitrogen) - and/or - epsom salts (magnesium and sulpher).

Good luck and keep us informed!

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Nothing like homegrown tomatoes!

HydroSan

What size is the pot?

I ask because I assosiate yellowing fans in the lower growth with rootbound plants, and I had some become rootbound at about 18" in 2 gal pots MG tends to burn plants easily, but this does not sound like fert burn

San

Nismoskyline

I guess it is most likely the pot is to small. Also i compacted the dirt very hard in the pot, which I heard is not very good for MJ. At least my outside plant is doing very good. My plant growing outside has huge leaves compaired to the ones in the pot and they are the same age. The sun leaves on the outside plant are around 4x the size of the other two. It is going to get cold where I live soon though, and some nights the temp. drops to around 20 some degrees. So will my plant most likely die? I would transplant it into a pot so I could bring it inside. But im sure by now the root system is way to massive to dig it up. If it starts to die from the cold should I take clones off it and grow them inside?