This is a Kimbrough satsuma, planted in late summer or so from a 3 gallon. It put on a flush of growth before winter and has taken the cold well too. But I've noticed some of the older leaves are getting very yellow. Is this a nutrient deficiency?

Here is an overhead view.


And an overall view.

Alan, welcome to the Citrus Growers Forum. We are delighted to have you as a member. Thank you for joining. The leaf symptoms seem to show a possible deficiency of magnesium. The visual symptoms of a magnesium deficiency shown up on the OLD LEAVES of the tree. In a magnesium deficiency, the lower center portion of the leaf is green and the tips and sides (margins) are yellow. Many times the green portion forms a delta type configuration on the lower center portion of the leaf. To correct a magnesium deficiency dissolve 1 tablespoon of Magnesium sulfate (Epsom Salts) in 1 gallon of HOT water, apply the COOLED mixture to the soil around the base of the tree once every two weeks until symptoms disappear. Most all fertilizer formulations, even many of the formulations that supply trace minerals, do not contain the trace mineral magnesium. Therefore, magnesium should be applied to the tree 3 or 4 times a year. Note also, that nitrogen up taken by the root system is slower during the cool/cold winter months, often resulting is a general lighter green color of the tree's foliage. Upon return of warmer weather the leaf coloration once again darkens. If you do not have the booklet "Florida Your Dooryard Citrus Guide", you should obtain a copy. The booklet is just 41 pages, contains most everything you need to know about growing citrus in your yard, copies for purchase are available from:

IFAS-Extension Bookstore
UF/IFAS Communication Services
PO Box 110011
Gainesville, Florida 32611-0011
352-292-2411

Again welcome to the forum. - Millet

Thanks, Millet. Can I correct the magnesium deficiency now, or should I wait until I fertilize the tree in spring to keep it from putting out new growth before a cold snap? Thanks for the heads up on the citrus publication, I will have to get it. I have the Louisiana home citrus production booklet from LSU, but it doesn't say much about nutrient deficiencies. I will post photos when the plant greens up.

You can add magnesium, at any time, as magnesium does not cause growth that would endanger the tree in a cold spell. It is nitrogen that would promote unwanted winter growth. Looking at your tree, you could also wait until your next fertilizing to add the Epsom salts. - Millet

Alan, You can also order the book on line here.

Ned

http://ifasbooks.ufl.edu/merchant2/merchant.mv?Screen=CTGY&Store_Code=IFASBOOKS&Category_Code=FVBK

Thanks Millet and Ned. I ordered the book, and also one on salt tolerant plants for my parents who live near the coast. I added the epsom salts today. By the way, my name's not Alan, it's Lucas; I picked this user name after a character in a movie.

Sorry Lucas.

Ned