My grapefruit tree hates me

7 years ago

This tree--with a 6" or so trunk, about 9-10' tall--came with the house we bought about a year ago here in the hot, dry southwest. The prior owner had been watering it on a timer--mini sprinklers 3 times a day for 3 minutes at a time. That was clearly not right, so I turned it off and deep soak it manually every so often (depending on how hot and dry it has been).

This year, it produced tons of fruit early on, but most of it dropped and only 2 dozen or so grapefruits made it through. All of the successful fruit was on the south side of the tree. When the baby fruit started dropping en mass, I noticed that the leaves were also starting to yellow.

I fertilized as instructed per the local university extension. When I fertilized it the first time, the tree was thrilled and got a lot of new growth. The second time, it didn't seem to notice. As the yellowing spread, I read this could be magnesium deficiency, so I gave it a recommended dose... to no effect. Now some of the leaves look like they are dying (brown/black spots spreading into dead leaves). I'm at a loss. I really want it to like me.

Newer growth is still green, older leaves turn yellow with green veining (magnesium deficiency?):

Others look more consistently yellow. You can see some of the brown spots in a few places:

Leaves at the top and west sides of the tree are the most sparse and sad looking (yellower, with more brown spots):

Any experts have any hits before I screw it up worse?

Featured Answer

evdesert 9B Indio, CA

7 years ago

last modified: 7 years ago

Your tree looks chlorotic and possibly magnesium deficient, mine look similar at this time of the year. Nothing to worry about especially if the new growth is still green. I would start fertilizing now, assuming your grapefruit tree is in ground. I use a product called Arizona’s best citrus food and have had a lot of success with it. It’s available at most big box hardware stores in AZ. Give your tree some time to wake up with spring warmth, before then, you’ll most likely see those yellowing leaves fall off in great numbers only to be replaced by new healthy green growth. Again, nothing to worry about, fertilize 3 times a year and your tree should reward you with more fruit next year.

This is what my Rio Red grapefruit looks like when I feed it with the fertilizer I suggested above.

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Comments (6)

socalnolympia
7 years ago
last modified: 7 years ago
Looks like a magnesium, iron or nitrogen deficiency. I'd give your tree some fertilizer.
jslazart thanked socalnolympia
Silica
7 years ago
last modified: 7 years ago
Looks like an iron deficiency. A foliar spray of iron chelate, or a soil application of iron sulfate to the root zone are the methods of controlling the deficiency. Do not apply iron sulfate as a foliar spray to citrus. There is a possibility of it also being a magnesium deficiency as socalnolympia wrote above. The correction method for a possible magnesium deficient citrus tree is a foliar spray of Epsom salts (Magnesium sulfate). Do not apply at high temperatures, or low humidity. Apply in the early morning or late in the afternoon. Use 4 ounces per gallon of Epsom salts completely dissolved in WARM water, and apply to the upper and lower leaf surfaces. Adding a good surfactant also helps leaf penetration. Note, correcting a magnesium deficiency does not necessarily re-green leaves already deficient. Lastly, your tree should be fertilized with a good fertilizer that also contains all the needed trace minerals three times per year equally spaced out during the growing season. When your tree produced a lot of fruit, the fruit absorbs much of the trees magnesium and iron supplies.
jslazart thanked Silica
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Dee
7 years ago
How often did you fertilize, how much and with what?
jslazart thanked Dee
jslazart
Original Author
7 years ago
I followed these directions, including the calculations and recommended timing for grapefruit: https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1671-2015.pdf. I used a fertilizer recommended by a local nursery, but I don't believe I kept the container, so I can't check what exactly was in it. I did follow online directions to try spraying the leaves with dissolved epsom salts about two weeks ago, but have otherwise tried to hold off doing anything until the January/February feeding window--so here we are.

One additional issue that might be contributing: there were brick pavers around the tree except for a maybe 5' "hole" for the tree. The canopy is much larger than the hole, so I couldn't fertilize right at the drip line. I've since pulled the pavers and should be able to do a better job this time.
myermike_1micha
7 years ago
last modified: 7 years ago
Great advice above!

If it were my tree and my yard, the very first thing I would do is have my soil tested for pH. Unless it's right on, it will usualy prevent any tree from taking up nutrients needed to prevent something like this. For me it's not a matter of patch work or quick temporary fixes, but finding the 'root' cause and then fixing that.
jslazart thanked myermike_1micha