Fertilizing inground citrus

9 years ago

After my last post, I started googling whether I should plan on my citrus going dormant in winter. I found an article in the local newspaper that said this:

"... the main fertilizing ingredient required for citrus tree vigor is nitrogen. Most soils have enough potassium and phosphorous. Generally, don’t apply nitrogen fertilizer in the first year. In the second year, apply 1/2 cup of ammonium sulfate per tree every six weeks starting in March. This fertilizer is 21 percent nitrogen. In the third year, increase to 1 cup per tree per application. In the fourth year apply 2 cups per application, increasing to 2 1/2 cups in the fifth through ninth years. In the tenth year, increase the ammonium sulfate to 4 cups per application for the remaining life of the citrus tree."

This is contrary to what I had understood so far. I thought we gave younger trees more fertilizer! Was I totally off? Plus, if I was, it's a bit late, I've been fertilizing everything, from the 4 years in ground plant, to the brand new ones planted this summer!

Also while this article tells you when to start fertilizing, it doesn't say when to stop! Other articles online seem to suggest stopping in November, and starting in March. Would love some advice!

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uncle molewacker z9b Danville CA (E.SF Bay)

9 years ago

Feed 'em PalmP or other fruit tree food. If you want them taller / bigger, bump up the N.... or simply add a bit of AS. The persimmons I have are all 6 months to 1 year in the ground and need to get far larger within my landscape... I do not care about fruit production - yet - therefore they get NitraKing : - ) - - happy feeding !

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Comments (6)

uncle molewacker z9b Danville CA (E.SF Bay)
9 years ago
last modified: 9 years ago
General guidelines are nice to have, but you need to tailor the feeding to your own specific situation(s).

Citrus does not go dormant, but its roots ability to uptake nutrients diminishes in colder soil. As the tree gets larger and produces more and more fruit, its nutritional needs increase. Early season flush growth needs lots of N, while latter growth for fruit development can utilize a greater spectrum of nutrients.

How that translates to my yards in northern California... I feed aggressively with high N (or mostly N) until the end of July. Then in August I begin switching to a lower N / balanced product such as Palm Plus or GRO-POWER so as to help the tree develop the fruit. I rarely feed after early September. NOTE the total seasonal amount I feed is targeted at twice the "recommended" amount - because.... most of my trees are: on a slope, mulched with wood chips, have neighboring established trees/roots, in lousy nutrient depleted soil ("fill"), and producing fruit.

Here is the dilemma [FOR MY AREA]: N late in the season will continue the foliar growth and this fresh Sept/Oct growth will likely be destroyed by any late November or December freeze. The flip-side is that I have found that a well-fed tree will tolerate freezes far better.

-George
kcandmilo
Original Author
9 years ago
Thanks, George! I was hoping you'd see this! I think I might start tapering off the Nitrogen around the end of August, and look into lower nitrogen options. I see that Gro-Power Plus is a nitrogen enhanced compost type product, which might be a good option to keep my soil in better condition. There seems to be a location not too far from me that sells it, I'll look into it!

Thanks so much for the detailed advice!

KC
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uncle molewacker z9b Danville CA (E.SF Bay)
9 years ago
you can get GRO-POWER " Citrus and Avocado " flavor from your local Ewing distributor; I buy the 40 lb bags 2 to 4 at a time. check out the other fertilizers they have. I use AS, NitraKing and PalmPlus too.

As with any granular fertilizer applied this time of the year... the challenge is to keep the fed soil properly hydrated and not burn roots. I have 100 lbs of NitraKing and 200 lbs of PalmPlus to get down before my end-of-August target [65 citrus, 7 Poms, .7 figs, and 3 persimmons]
kcandmilo
Original Author
9 years ago
I have two Ewings near-ish me! I don't have as many trees as you though! I have two persimmons, an apple, a plum, a pluot and 9 citrus! I know i am going to sound amazingly stupid, but I haven't even thought about fertilizing my non-citrus trees! Mainly because they all have been fruiting without fertilizer for the last 4 years, and they aren't even in good locations! Sigh, more research! Any idea if all fruit trees are as nitrogen greedy as citrus?

KC
kcandmilo
Original Author
9 years ago
Actually, George, I want them smaller! They are planted under a big protected oak, and I want to keep them from hitting its canopy, and also they have more of a chance of getting sunshine lower down. That's a whole different problem though!

Will check out the PalmPlus at Ewing when I go get the citrus food. I planted an avocado too this year, I should probably start feeding that too! Can't believe how long it is taking me to connect the dots and realize fruit trees need food!