When & How to Fertilizer Your Fruit Trees
Make your organic orchard bountiful by fertilizing your fruit trees.
In our research-based video, Tricia explains IF, when, and how much to fertilize your fruit trees. Keep reading here to learn more, and use our online fertilizer calculator.
When to fertilize fruit trees
Right before bud break is the perfect time to fertilize your fruit trees. If you miss the moment and the trees have begun to bloom, you can still fertilize until June.
Don’t fertilize in late summer or fall, though, because the new growth put on by the tree can be damaged by frost.
The earliest time to fertilize? One month prior to spring growth.
Measure fruit trees to see if they need fertilizing
Not all fruit trees need fertilizer every year and they don’t need it in the same amounts.
Too much fertilizer means lots of leaves and shoots, and not a lot of fruit.
Luckily, fruit trees are pretty good at telling you what they need.
If the tree was pruned more than it typically is pruned in one year, don’t fertilize.
Begin your assessment of a tree by locating last year’s growth rings. The growth ring is the point on the branch where the tree started growing the previous year.
Measure from the growth ring all the way out to the end of the branch. Repeat these measurements at several spots around the tree, and average them as the previous year’s “annual growth” of the tree.
Use this chart to evaluate your tree’s annual growth. If the tree’s number is at the low end of growth, then you should fertilize the tree this year.
* Non-bearing peaches and nectarines should grow 18”-24”.
* Bearing peaches and nectarines should grow 12”-18”.
* Non-bearing apples and pears should grow 18”-30”.
* Bearing pears and bearing non-spur type apples should grow 12”-18”.
* Bearing spur apples should grow 6”-10”.
* Non-bearing plums and sweet cherries should grow 22”-36”.
* Bearing plums and sweet cherries should grow 8”.
* Non-bearing, tart cherries should grow 12”-24”.
* Bearing tart cherries should grow 8”.
How to choose fertilizer
There are also specially formulated fruit tree fertilizers.
To provide micronutrients for your trees, add compost.
Back to math class—calculate how much fertilizer your fruit tree needs with our online calculator
For those of us who did not excel in math—fear not—we will walk you through the fertilizer calculations AND we have an online calculator for you.
So stop worrying that this is one of those awful Math Word Problems.
Rule of thumb: The amount of fertilizer is based on the age or size of the tree.
Trees need 0.10 of a pound of actual nitrogen per year of age, or per inch of trunk diameter (measured 1 foot above the ground). The maximum you should give a fruit tree in a year is 1 lb. of actual nitrogen.
The NPK numbers on fertilizer show the percentage of nutrients per pound of fertilizer. N, P and K refer to actual nitrogen, phosphorus, and potassium.
For example: If the N is 10 then there is 0.10 of a pound of actual nitrogen for every pound of fertilizer.
To calculate how much fertilizer to apply: divide the amount of actual nitrogen the tree needs by the percentage of nitrogen in the fertilizer.
In the video, for example, Tricia’s five-year-old apple tree needs a half a pound of nitrogen. The E.B. Stone Fruit Tree Fertilizer has a 7 for N. Half a pound or .5 divided by .07 equals 7 lbs, which is the amount of fertilizer to apply to get the proper amount of nitrogen.
We make it EASY for you to calculate the fertilizer for each tree. Our online calculator does the math for you.
How to apply fertilizer to fruit trees
There are two ways to apply fertilizer to your trees.
The easiest way is just to spread the fertilizer on the ground, rake it in, and then water.
Don’t start fertilizing next to the trunk. Start a foot from the trunk and spread fertilizer evenly all the way out to the drip line.
The drip line is at the perimeter of the tree’s furthest reaching branches.
Digging a series of small holes is another method of applying fertilizer. It is a bit more work, but it ensures the fertilizer is getting to the tree roots.
To make the digging job easy you can use an auger attachment with a cordless drill.
Dig the holes six inches down and 12”-18” apart. Start drilling the holes a foot outward from the trunk and continue on to the drip line.
Take the fertilizer you’ve measured out according to the recommended rates and sprinkle a little in each hole until it is used up.
This is great for making sure less water soluble nutrients like phosphorus or beneficial mycorrhizae in the fertilizer make it to the tree roots.
Once you have finished fertilizing, spread an inch of compost over the top and water well.
For more information on all aspects of fruit trees—choosing, planting, controlling pests, using your harvest—browse our storehouse of research-based videos and articles in Fruit Tree Central. Staff favorite books on fruit trees are The Home Orchard from UC Davis, along with The Fruit Grower’s Bible and Landscaping With Fruit.
Keep on living the dream with your organic orchard, now that you know when and how to fertilize your fruit trees.
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