Chlorosis.

What is the answer to this problem? What should I use on the plants? Thanks! They are in pots by the way. should I change the soil? Please say no! LOL

The textbook answer: Chlorosis is typically caused by an iron deficiency. Foliar spraying with chelated iron can help correct the problem (or at least its symptoms: yellowing leaves, with green veins still showing.

Iron is a trace mineral in the soil, and rarely is it truly lacking. (If these potted plants are in a soiless mix, this general truism may not apply.) In most cases the root cause of the problem is that the soil's pH is too high, which binds up the iron and prevents it from being usable to to the plant. It doesn't mean you have to re-pot the plants, but you should take the necessary steps to check and - if necessary - adjust the pH level.

Plants receive nutrition only through the absorbtion of nutients and micro~nutrients through their cell walls by means of a process called cation exchange. Cation exchange is the replacement of one positively charged ion with another.

Cation exchange efficiency is highly dependent on soil pH and available micronutrients: positively charged ions of specific elements. Cation exchange potential is optimized when both soil pH is appropriate and the required micronutrients are present in the soil in appropriate amounts (vanishingly small).

Adjusting your soil's pH in the absence of these elements would prove fruitless, as the required elements to provoke cation exchange are the critical components for enabling plant cell growth. With these elements absent, there is nothing to exchange.

Chlorosis is, essentially, a condition related to root cells' inability to obtain specific micronutients from the soil they are growing in, and thus is an indication of poor cation exchange potential in the soil.

Our own experience with this was that our soil pH was at the optimum for our indoor grapefruit trees grown from seed, yet the micro~nutrients were absent. While iron is one of the critical micro~nutrients, others, such as managnese, are indicated in this article below:

http://www.mortonarb.org/plantinfo/plantclinic/hortcare_chlorosis.pdf

It's a great introduction to dealing with the problem.

Please let me know if you have any questions about this article. I'll be pleased to answer.

Adam.

Oh, by the way..., imagine..., once you start to learn to control these aspects of soil condition..., how your plants are going to grow?

And it can be done organically.

Adam.

Can you post the article in something other than Adobe? It seems to have errors on it (C-map errors) and doesn't fully load/show printed words past page 1. Also kept getting other error messages.

Didn't you post this on another thread, Adam? I don't remember that happening on that thread.

Yes, I posted it on the other thread, asking questions on the same topic (yellow leaves, green veins).

Uhm..., all articles on that site are in Adobe, and I have no clue how to get them out.

I'd bet you a dollar GardenWife knows. She's a computer genius.

Adam.
PS: I am not having this problem when opening the link.

This message was edited Wednesday, Feb 26th 11:40 PM

Hmmm...thanks Adam. Maybe my puter is not accepting it all. Have no idea why. Sure looks like good info there, I just tried again but to no avail. I'll clean out the puter, refresh, and try again tomorrow.

And by the way, that is probably the best article I've seen pertaining to chlorosis. Very informative. Much obliged!

Very good article Aotearoa.

Dale, In our area we have high alkali soils. While we have plenty of iron in our soils it is not bio-available to the plants because of the calcium content of the water AND the soils. In order for the release of the iron to happen we have to add sulfur to the soil usually done in the form of magnesium sulfate. Soils and water vary so much in different parts of the country that I would want to ask somebody in your area what to do. It would be a good idea to call your local University Extension Service and ask them the question presented here so you aren't throwing things at the plants and hoping that one of the things will stick.


Good luck.