At the end of this month, no more fertilizers, except for minors or epsom salt or gypsum. If you apply fertilizer, the tender growth spurts could extend well into the cold season when they will be prone to damages. This is the pracice that I do here in our region. We have frost as early as October, but last year we did not have frost until around thanksgiving.

So when do you stop fertilizing your inground citruses?

I resume fertilizer application in mid-February when the last major rains come and pushes the fertilizer down into the proper root zone depths where they will be needed during the spring flush growth and having abundant blooms. From March to July, I apply various fertilizer depending upon the size of tree and how much harvest I took.

Growers in this area normally fertilize in September for the last time of the season, then resume in February, traditionally after the full moon. We seldom get frost before the third week in December.

In the Gainesville, Fl area I'll put my last fertlizer application down around late September for in-ground citrus. We typically get our first frost sometime around the first week of December.

.....Alan.

In SE Texas we normally fertilize the end of January and again in 45 to 60 days later. I never fertilize after the first of June

I am going to try to do something different this year. Since I noticed that my citrus are growing througtout the year even during Winter when the tempt is 40 at night and high 60's during daytime I'll keep on fertilizing in dilute amount and see what happens.
I also noticed that even if the tempt goes below 38 but if I just keep the plant covered, the tender leaves stay green.

Do you use less fertilizer for the last application?

For the newer members of this forum, it is important to note that the recomendation to stop fertilizing citrus trees in August/September because of the coming cold weather, is a recomendation for IN GROUND TREES GROWN OUTSIDE. For containerized trees grown in greenhouses, or trees that can be moved to a warm location throughout the winter months this does not apply, because there is no danger of freeze damge. All of my trees (100+) continue to receive fertilizer applications throught the winter months, but in reduced amounts. In container citrus, for fruit development and fruit maturity, higher temperatures and good leaf activity should be maintained. Irrigation with a nutrient solution should be done even in winter. - Millet

Karl:
Since we are both in zone 9 but I don't know if you live close to the ocean and there is a big diffrence in temperature if you live inland it is best that you follow what everybody is suggesting. Sea is a good buffer so the tempt in my area does not go to the extreme.Last application should be normal as it is suggested. And what Millet said is true to the point. I have a lot of citrus that are still in the pots and they will be protected from adverse weather if need be and although the tempt hovers around the low 40's at night I noticed that they still grow so this winter I will start fertilizing them in lesser amount. But with my citrus planted on the ground I think I'll just leave them alone. They are big enough to take care of themselves. (Maybe).

Wow Thanks Millet I was just about to go UM since i was thinking i needed to Fertilize my Container citrus ..

PS what do you use for yours ? Tammy

Benny
I am about 6 miles from Vermillion bay and the winters are mild. Last year I fertilized the container citrus late, since I knew that I would get them to shelter if needed. Turns out that I only moved them to my heated shop on two occasions and in both instances it never got as cold as predicted.
Honestly Benny, I don’t recall much growth through the winter, but will be more observant this year.
I have been using the Miracle grow slow release on the in ground (not for container citrus) and it’s about to drive me broke with 12 trees. I switched to the fertilome citrus and pecan this year and it seems to be a very good product.
Like Tammy, I am also interested in the fertilizers that are use by others.
Karl

Tammy I just switched to a 15-5-15 that also contains 5% calcium and 2% Magnesium, plus trace minerals. This is a 3-1-3 ratio. There are many commercial fertilizers with all sorts of nutrient ratios. For containerized citrus, I believe, they must be chosen according to the replacing minerals and their ratio. 5-1-3 is the ratio of the main elements lost from a citrus orchard, and fertilization must respect this ratio when the mineral content in the leaves is satisfactory. In other words 5-1-3 is the ratio that citrus trees absorb nutrients from the soil. Obviously, in cases of overdosage or deficiency of one or more elements this ratio must be changed to a more appropiate one. The problem is that it is hard to find a commerical fertilizer with a 5-1-3 ratio containing all the trace minerals. 15-5-15 with its 3-1-3 ratio is close. I also really like the 5% calcium and 2% magnesium. Also, almost all of the nitrogen is derived from a non urea sourse. I do not like fertilizers with a nitrogen source high in Urea. In fact, I believe, a totally free urea source would be best. Lastly, In ground citrus trees are not as particular about fertilizers, but I do believe the proper ratio is very important for trees confined to a container, unless the container is leached often. - Millet

Millet and others: If you simply mix 1 cup of 15-5-15 with 1/2 cup of Ammonium sulfate, the result would be almost like 5-1-3. And ammonium sulfate is super duper cheap!

Here's the mathematical solution
N: (1 cup x 15 + 1/2 cup x 23 )/(1.5 cups total) = 17.66667
P: (1 cup x 5 + 1/2 cup x 0)/(1.5 cups) = 3.333333
K: (1 cup x 15 + 1/2 cup x 0)/(1.5 cups) = 10

Which reduces to 5.3-1-3

To be exactly 5-1-3, one has to mix 0.4348 cups of ammonium sulfate with 1 cup 15-5-15.

And you can subsititute lbs for cups, and the ratio 5-1-3 will be arrived at, very cheaply.

As always, it is easier for me to remember 1 is to 1/2 cup and live with a nice approximation of 5.3-1-3 ratio than remembering and measuring the 1 is to 0.4348 cup ratio to get exactly 5-1-3 formulation, but each to their own.

Engilish please .. No kidding
Thanks Millet and Joe .Ill go check out what i have been using and see if i have the right stuff . If not ill get some Tammy

Joe, as always you come through with the answer. I can purchase Ammonium Sulfate in 50-lb. bags from the same place I get the Peters 15-5-15. With the extra (NH3)2SO4 I will fertilize the grass. Also Ammonium Sulfate is acidic in reaction, which will be good for citrus. Thanks - Millet