I am trying to grow Flying Dragon to a size big enough to graft next year, my problem is the new leaves look almost whitish yellow. On other plant material, this symptom would be suggest a micro deficiency. My well water is very hard, high TDS around 690 and contains alot of bicarbs which I have heard FD doesn't like. So, I added about 1 tsp/gallon of rain water a high N food with micros. Still very yellow.

The bearing grafted orange and key lime do not show such issues and they get the same treatment.

Thanks for any thoughts.

Can you measure the pH of your soil? It should be in the 5-6 range. If it's much above 6, you may either need to lower it or to use a chelated form of nitrogen.

I'll check the pH. I know it doesn't like highly alkaline or acidic soils.

What is "chelated N"?

Here's an interesting ditty on the subject:

Q: What is the best pH for a citrus tree?

A:The ideal pH for a citrus tree is 6.0 to 6.5, if it's on citrus roots, or 5.5 to 6.0, if budded/grafted to Poncirus roots or one of the Poncirus hybrids (citrumelo, citrange, etc.) Ideally, you should have your soil tested. A local extension office may do it for you, or even a local college or high school with a chemistry dept. Or you can buy fairly cheap pH meters or even cheaper pH testing paper (not very accurate, but perhaps close enough). For a meter, the traditional way to measure pH is to mix a soil sample with an equal volume of water, let it sit for about 1/2 hour, then test it with your pH meter. If the pH is too low, you'll need to bring it up with some form of lime. If it's too high, you bring it down with acid-forming fertilizer, sulfur, iron sulfate, aluminum sulfate, etc.

Light-color leaves are more likely to be caused by too-high pH than too-low, although if the pale green is solid (same color veins as background, no striping, etc.), it seems likely to be more due to a lack of nitrogen, than to a pH problem. If adding nitrogen fertilizer does not fix the problem, and the newer leaves remain pale yellowish green, with no pattern, I'd suspect sulfur deficiency -- many commercial fertilizers contain no sulfur.

Vinegar, lemon juice, etc, are pretty much worthless for soil pH management. Yes, they are acids when you use them. The problem is that as they biodegrade in the soil, they cease to be acidic. So the effect is very short-term.

In an alkaline soil (too high pH), citrus trees tend to develop deficiency symptoms for iron (green veins on an otherwise pale yellowish leaf), manganese (green veins with green borders spreading out from the vein, on the leaf, on an otherwise pale yellowish leaf), zinc (same as manganese but the leaves are also dwarfed), or Magnesium (an inverted "V" or "Christmas-tree" shaped area of green at the base of the leaf, with the upper/outer parts of the leaf yellowish or orangeish. Fe, Mn, and Zn deficiencies will be seen mostly on the youngest (top) leaves on the plant; Magnesium deficiency tends to show up first on the oldest (lowest) leaves.

Too-low pH (acidic) soils often result in a plant that looks perfectly healthy and normal, with dark green leaves. But the plant just doesn't grow vigorously and doesn't make much fruit. It's stunted, overall.

http://members.fortunecity.com/pjsauber/FAQ.htm

Trifoliata seedlings will do that at times. I have had that happen quite often, it seems to correct itself over time. Last time I had that happen the
ph was 5.3 and it was only on a few of the new branches. People mistake it for variegation...

Mark, Yes, I'm the author of the "ditty."

A chelator is a chemical with long "arms" that can wrap around an iron atom, protecting it from binding to a too-alkaline soil. EDTA is a commonly used one, but there are many others. A label will always state if a product contains chelated iron. Chelated forms are available at higher pH than non-chelated forms. Other elements are occasionally also chelated, but iron is by far the most common.

pH is 6.61. I need to bring it down.

Laaz, I've lost a couple of plants to this, they never corrected themselves. Based on some research it looks like it's a Fe deficiency induced by a pH that's a little too high.

Fe, Mn, and Zn deficiencies will be seen mostly on the youngest (top) leaves on the plant; Magnesium deficiency tends to show up first on the oldest (lowest) leaves.


Thanks fellers...

Personally, a growth medium having a pH of 6.6, I would not worry about it. - Millet (1,226-)

The new growth on FD and trifoliata will normally be almost white and turn green as it ages.

If I spoke of chelated N, it must have been a typo. I've never heard of chelating N. Nitrogen, either as the ammonium (NH4+) or nitrate (NO3-) form, is available at all common soil pH levels, so chelation is not necessary. Soil pH will affect whether organic nitrogen (including urea) converts just to ammonium (all pH values, all temperatures above freezing), or if it continues on to become nitrate (only in soils with pH greater than 5.5 and temperature greater than 70 °F).