How to Grow No-Spray Organic Applescomments (9) September 22nd, 2011
Apples may seem like the last bastion of pesticide-dependent gardening. In many commercial orchards, apples are sprayed 10 to 20 times per year. It's not hard to find organic home gardeners who still believe it's nearly impossible to grow good fruit without pesticides. Furthermore, most people probably expect organic fruit to come with a few spots or chew marks. I used to rely on insect traps and biological sprays, and I would still have fruit that was covered with disease and infested with worms. Then I found a way to grow pristine apples without using any kind of spray.
Successful organic fruit-growing starts with selecting varieties that are inherently disease resistant. This important first step eliminates half the problem.
The major apple diseases are apple scab, powdery mildew, and fire blight. Of these, only apple scab really affects the fruit. More than 50 years ago, Purdue University, Rutgers University, and the University of Illinois established a cooperative breeding program. Since then, at least 53 scab-resistant apples have been released.
Selecting apple varieties
|11 Flavorful, Disease-resistant Apples
Sources for apple trees
How rootstock selection affects tree size, years to fruiting, and sturdiness
Just as important as selecting disease-resistant varieties is rootstock selection. I recommend a tree no taller than you can reach. But don't expect anything labeled "dwarf" to be small enough. To the fruit tree industry, that term means anything from 4 to 16 feet. You will know how big you can expect your tree to get only if you know the name of the rootstock.
The most dwarfing rootstocks are M27 and P16, yielding trees of 4 to 7 feet. Next are P22, Bud 146, and Bud 491, which produce trees 5 to 10 feet tall. Bud 9 and M9 create trees 6 to 12 feet tall. The largest I recommend are 8- to 16-foot trees, which you'll get with P2, O3, and the virus-resistant M9 EMLA. In addition to the rootstock, the vigor of the apple variety and soil fertility also affect the size of the tree.
|More on growing apples in the backyard orchard, plus links to apple recipes...|
The root systems of dwarfing rootstocks are relatively small or they are brittle. Either way, they cannot adequately anchor the tree, nor do they have access to moisture deep in the ground. Therefore, all dwarf trees must be staked and regularly irrigated.
Thinning increases the size of the remaining fruit
Thin apples within 35 to 40 days of fruit set. The sooner you do it, the better the results. All things being equal, fruit size should increase, along with next year's bloom potential.
Why so early? Once the apple blossom has been pollinated, the fruit begins to form the seed. The endosperm in the developing seed starts producing the plant hormone gibberellic acid, which promotes enlargement of the fruit. But gibberellic acid also inhibits the development of next year's flower buds, so the more seeds produced, the more gibberellic acid and the fewer flowers and fruit next year. Many apples tend to bear heavily every other year, with little to no fruiting in between. Thinning shortly after blossoms fall helps reduce this tendency and results in more even harvests every year.
I thin to the biggest fruit, leaving one about every 6 inches. In every cluster of apple blossoms, there's one in the center that's slightly bigger and slightly earlier than the others. Orchardists call this flower the king blossom. Because it opens a day or two before the others, the king blossom usually gets pollinated first and therefore produces the largest fruit. However, if the largest fruit is blemished, remove it and choose another. If there's no appreciable difference in size among the fruits, select the one with the thickest stem.
|Most clusters of apple blossoms have a "king" blossom in the center. It's larger and earlier than the rest and typically makes the largest, earliest fruit.||Thin fruit five or six weeks after blossoms drop; the tiny apples will be 3/4 to 1 inch in diameter.|
|Thin to the largest fruit. If there is no discernible difference, choose the one with the thickest stem.||If the largest fruit is blemished, remove it in favor of a smaller but perfect fruit.|
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