UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee , FL 34972-2578

Phone: (863) 763-6469

E- mail:  dfculbert ifas.ufl.edu

 

 

 

 February 22, 2006

Feature Article - for release the week of February 26, 2006

Dan Culbert - Extension Horticulture Agent

 

 

Help Dooryard Citrus recovery

 

One sign of spring is the smell of citrus blossoms in the air.  Along with the bloom, new leaves will soon be rapidly growing, looking to the soil for needed nutrients.  Today’s column will discuss the specific nutritional needs of citrus and offer suggestions of appropriate fertilizers for dooryard citrus trees.

           

Many dooryard citrus trees have been hammered by two years of hurricanes, and will be itching to put on new growth this spring.  Likewise, if you have escaped citrus canker quarantined areas and have been able to plant a new dooryard citrus tree, remember that fertilizer will insure young trees get off to a good start.

 

The regular application of the correct fertilizers is needed for developing young trees.   Fertilizer will also be needed to produce large crops of good quality dooryard fruit as the tree matures. While fertilization of many other plants in the Florida Yard may not be necessary and may contribute to runoff, for citrus trees it is necessary for success.

           

Over fertilizing may be just as harmful as not applying enough.  Excess nitrogen can produce lots of leaves and reduce fruit production.  In some cases, over-fertilization can burn, causing injury or death of the tree. 

 

Two different fertilization schedules are suggested: one is for young, non-bearing trees, where leaf and stem growth is maximized and fruit production is reduced.  Later on, a mature tree schedule is used where tree growth is minimized and fruit yield and quality are maximized. 

 

For baring trees, the University of Florida recommends three applications per year just before new flushes of growth appear. Typically in our area, the right times will be first in late February, again in May - June and finally in October.  Avoid fertilizing citrus trees in the late fall or winter to avoid succulent growth that will freeze easily.

 

What kind of fertilizer is best for dooryard citrus?  Garden centers often sell special Citrus fertilizers.  Look at the label to see if the product contains the necessary nutrients.  An appropriate analysis for young trees is a product with equal amounts of nitrogen, phosphorus and potassium.  This is called a balanced fertilizer, such as 8-8-8 (N-P₂O₅-K₂O). 

 

Citrus fertilizers should also contain magnesium (1.6%), manganese (0.4%), copper (0.4%) and boron (0.2-0.025%).  Be careful to avoid those products with high amounts of chlorine. And choose those products that have larger amounts of the nitrogen in slow release forms.

 

Fertilizing Young Trees

If this is the first year after planting the dooryard citrus tree, give it ½ to 1 pound per tree, applied 5 to 6 times per year.  During the second year, add 1 to 1½ pound per tree, but reduce the frequency to 4 to 5 times annually.  At the third year after planting, use approximately 2 pounds per tree, and increase by one pound during both the fourth and fifth year. After this time, the tree should be bearing and considered a mature tree.

 

The amount applied in each application can be gradually increased to about one pound per year up to a maximum of eight pounds.  This would mean that a fully-grown tree would be receiving approximately 24 pounds of fertilizer in three separate eight-pound applications.

 

Fertilizing Bearing Trees

Fertilizing bearing, mature dooryard citrus is a rather inexact science.  There are many variables which can affect fertilizer use.  If grass is grown around the tree, if there are other nearby trees or ornamentals, or if heavy irrigation is offered, additional nutrients may be needed for recovery from storms or for optimum tree growth. 

 

Consider using higher analysis, mixed formulations such a 12-0-12 or 15-0-14 on mature trees.  Controlled-release fertilizers that slowly release nutrients over a 6- to 9-month period can also be used. Check the label for instructions on the right amount of fertilizer to be applied per application and for annual totals.  Organic gardeners can also use composted manures – contact our office to get help calculating how much will be needed.

 

 

Tree condition should be used as a guide to rates of applied material.  If you notice deficiencies, provide the trees with more material.  If there is luxuriant, vegetative growth, reduce these amounts. 

 

A nutritional spray may be used when minor element deficiency symptoms develop.  These fertilizer problems can appear if the soil contains marly, alkaline soils. Iron deficiencies may occur and should be corrected by using soil-applied iron chelates, which are quick acting forms of this important mineral. There are many pre-packaged nutritional spray mixes that are satisfactory.  Your local garden supply dealer should be able to recommend which material is best.

 

Fertilizer should be spread over the soil, not clumped or piled around the tree.   During the first year, cover the planting basin area.  For established trees, a good rule of thumb is to spread the fertilizer as many feet beyond the drip line of the canopy as the age of the tree in years (up to ten).  Fertilizer near or in contact with the trunk should be avoided. 

   

Master Gardeners can answer many questions that you may have about managing other dooryard fruit.  I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on springtime landscape recovery, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.   Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 5 PM on Tuesday afternoons.  

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Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.  Florida Cooperative Extension Service / IFAS / University of Florida.  Larry A.  Arrington, Dean Last update: 02/23/2006 .  This page is maintained by Dan Culbert