"David Hare-Scott" wrote in message
...

"bluesardine" wrote in message
...

We have a lemon tree in a pot on our terrace in Spain.
The leaves are turning yellow, it gets enough water, has stones in
bottom so not water logged, situated in bright sun all day.

Any ideas, Pete



Yellow leaves in citrus are a sign of several things but this is probably
a
mineral deficiency. Feed during the growing season (spring and summer)
with
high nitrogen fertiliser (eg chicken manure) or "citrus food". Don't
overdose
especially if using the granulated synthetic chemicals which is very
strong or
all the leaves will fall off. Several small feeds are better than one big
one
and water it in well. If this is the problem you will see results in a
few
months. If this doesn't work give them some trace element supplement.

David

Trees like lemon manufacture their own food. They are autotrophs. They
however provide food for heterotrophs like humans. While your advice may be
a good thing, calling fertilizers plant food is not. People who say they
feed trees flunked photosynthesis. Providing essential elements sounds like
a promising treatment if they are really lacking. The problem is that no
one has done optimal fertility research for trees to understand exactly what
elements are lacking. No one really cares about that research. However
they fund research they do not understand.

Its hard to properly mulch a tree in a pot. That's you problem right there.
If the pot was huge that would be better. Composted wood and leaves will
provide many essential elements while stimulating benefical bacteria and
micros in soil that make elements avalaible, when applied correctly.


here are two articles addressing the "feeding of trees"
Troubles in the Rhizosphere
http://www.treedictionary.com/DICT2003/shigo/RHIZO.html
Improper Fertilization (See A Touch of Chemistry)
http://www.treedictionary.com/DICT2003/shigo/CHEM.html

Planting
http://www.treedictionary.com/DICT20..._planting.html

Mulching -
http://www.treedictionary.com/DICT2003/M/mulch.html

Pruning
http://www.treedictionary.com/DICT2003/tree_pruning

Tree Farming and Related Problems
http://www.treedictionary.com/DICT2003/SOUND/

Troubles in the Rhizosphere
http://www.treedictionary.com/DICT2003/shigo/RHIZO.html

Sincerely,
John A. Keslick, Jr.
Consulting Tree Biologist
www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.