4 year old Myers lemon showing signs of some sort of mineral/metal deficiency. The leaves are a nice green color but the veins are yellow. I have looked at several pictures of deficencies and can not find one that looks like this. I have 5 citrus trees and the Myers is the only one showing any sign of trouble. We also picked the last of the 7 lemons this tree produced (first usable fruit). The tree is about 2ft tall and in a 3 gal pot. It was repotted this past fall with new soil/sand/perlite/chunkies. Its fertilized with a nursery fertilizer containing minors. Last fertilized in September. All the trees are treated the same and water when the water meter says dry. All trees are wrapped with Christmas lights and pot temp stays right around 80 while the room ambient temp is 68-70. I just did a PH test and the PH is WAAAAAAY alkaline. Could this lock up the nutrients being delivered to the tree?

What might this deficiency be and what is the correction?

TIA Andi

Hi Andi, A nitrogen deficiency first shows up on OLDER leaves with newer leaves still showing green. Starts with yellow/orange veins with some green out on the sides. Iron, Mananese, Magnesium and Zinc deficiencies are OFTEN caused by high pH (alkaline) conditions rather than an actual shortage of minerals. I see you are keeping the tree in a active growth atmosphere by warming the soil with lights, and the canopy of the tree is placed in a warm room of70F, yet you witheld all nurshiment by not feeding the tree since September (four months). I assume the tree is placed in front of a southern window receiving good light. Why have you not nurished the tree? Nitrogen is VERY water soluble and is easily leached from the "soil." You said the soil was very alakline, but did not say what the pH was. Which pH test method was used in order to obtain the growing medium's pH? - Millet

Hi Millet,
Thanks for this great forum. Really nice format and nice folks too.

I did the pH test with the run off water as suggested in a previous post. The pH tester I have is one where you add a capsule and the soil or water. Shake and wait 30 min for results. On my tester very alkaline(8+) shows as a bluish green color. The color that showed on the test was almost pure blue. I tested the water I use for watering and it was at the neutral point.
I am unable to find the test papers here and can't really afford the $100+ for a handheld meter.

The "no food since September " is a bit misleading as the Nursery fertilizer with minors is a slow release( I negelected to add this little point). This is used every 4 months and will be added again in January. Andi

Andi, concerning the "Deficient" leaves on the Meyer Lemon tree. How many leaves are we talking about? Are they only the new leaves, old leaves or both? If they are the oldest leaves, and if the yellowish veined leaves also have a dull cast to them, the tree could just be casting off the aged and dying leaves. Meyer Lemons drop leaves from time to time. You can lower the pH of the growing medium just by the use of an acid type fertilizer with formulas such as 21-7-7, 25-10-10 or by other methods.. If you send me your mailing address (use the private message system available on this forum) I will mail you a really HELPFUL small booklet titled "Understanding pH Management For Container Grown Plants". - Millet

I have come to the conclusion that the high soil pH has "locked" the nutrients, therefore they are unavailiable to the tree. To overcome this I have started an experiment until I can figure out why the pH is so high.

I have lowered the irrigation water to pH of 5 by the addition of vinegar. I have flushed the trees soil with this water. Hopefully this will lower the soil pH enough to allow the tree to take up badly need nutrients. I all the trees their normal feeding even though its about 2 weeks early. The single Myers Lemon is the only tree involved in this experiment since its the only one showing distress. The other Myers Lemon,Key Lime,Sweet Orange, and Calamondin are watered as usual with un-altered water. I will keep you posted as to what the results are.

I am at a loss as to what is happening here as all the trees have the same soil medium.Andi

Vinegar, being an organic acid will work for a very short period. Organic acids just do not last very long. It is common to use mineral acids such as nitric, sulfuric and phosphoric acids for lowering the pH of irrigation water. Hydrochloric acid would also work to lower the pH, but is not commonly used because it supplies chlorides, which are not a wanted additive in the growing medium. - Millet