First my compliments for this great forum. (tnx Laaz)

I have (been growing/collecting) citrusplants for about 15 years now, and without any "leave problems"(apart for some slight iron deficiency)
Since last year I have some problems with the clementine citrus, the effect oucurs mainly in spring (after the first flush) in the older leaves. The young leaves are not affected. Strange thing is that it only oucurs in the clementines, and slightly in the calamondins. The other citrus plants are not affected. Are clementines more sensitive for this type of deficiency?
My question: Is this potassium deficiency, or some other deficiency?

Any help, suggestions ...appriciated.

Erik

http://members.fortunecity.com/pjsauber/Citrus%20deficiencies.htm#

Thanks

Sometimes they appear on Meyers, clementines, grapefruits, and Kumquat types. I haven't seen them on Satsumas, sweet oranges, blood oranges, navels and valencias. Seems to be also related to temperature. During late fall to late winter, these splotches of yellowing are pronounced, but even if I don't do anything to the soil like adding fertilizers, they minimize or disappear as warmer temperature sets in.

Joe,

Thank you for your answer. Yes indeed (most of) these splotches do disappear during the summer. Maybe it has something to do with the mobility of minerals in the plant during the time that the soil / roots aren't warm enough and the surrounding temps are. I think the root mineral(potash?)uptake is at that point not enough to feed the first flush?

The advantage is that I can see the difference between the satsumas and the clementines very easy at 100 yrds.

I have a Verna lemon that has leaves that have more yellow on them than Erik's. These leaves are new ones that grew in August last year and new ones from this year. They are more yellow with dark green veins.

Some of the lower leaves (older than last year) are drooping and some have been very slightly yellow. These have just started to fall off.

The tree hasn't been overwatered but has been fed regularly. I gave it a good foliar feed the other day but the bottom leaves are still dropping off - about 1 - 2 a day.

Is this some sort of feeding deficiency?

The tree is 4ft high and in about a 10 inch wide container, so I'm not sure if this is a case of the tree needing to be repotted. There seems very little spare room for root growth.