How to Grow Apple Trees

apple-tree-in-orchard

While it takes a few years before you can harvest apples after planting your very own orchard, with time and patience, you’ll be able to revel in the fruits of your hard labor.

Here’s a breakdown of how to grow apple trees.

Types of apple trees

There are an endless amount of apple trees you can grow. The Maine Heritage Orchard’s searchable database is great reference for apples that are known to produce well in Maine. You can look up apples by name to learn more about their uses (from cider to livestock feed to molasses), season of fruit maturity, and more.

Because the fungal disease called apple scab can affect apples grown in Maine, you might consider planting a scab-resistant variety, such as Liberty — though resistance may be waning in once scab-resistant varieties. Susceptible varieties, such as McIntosh, Cortland, Spartan and Empire, will require fungicides to control scab; organic fungicides are available.

Site selection

Ideal climate for apple trees 

The best sites for apple trees have well-drained, deep, fertile soils; protection from wind; and full sun. A gentle slope with six to eight hours of full sun per day is ideal. Good airflow moderates fungal diseases. Choose the site on your land that encompasses as many of these features as possible.

On the other hand, avoid a site with extreme exposure. Wind greatly dehydrates trees, reducing their overall performance and winter hardiness. On exposed sites, plant windbreaks to the windward side. Some orchardists paint the trunks of the trees white with interior latex paint to reduce bark splitting during sudden winter temperature fluctuations; however, this is not suitable for certified organic production.

For spacing, a standard apple tree needs 30 feet, a semi-dwarf needs 15 feet, and a dwarf needs 10 feet of space per tree.

Soil

Apples are a long-lived crop (even the relatively short-lived dwarf trees can live for 20 years), so you have to prepare the soil before planting them. A year or two of forethought and ground preparation can result in decades of successful fruit growing.

Plan ahead

A soil test determines your soil pH, what your nutrient levels are and which amendments are needed for balanced tree growth. Then you can prepare future tree locations, mix in aged compost and needed amendments, and add mulch to keep out weeds and continue to build the soil.

If you want to plant cover crops, buckwheat followed by a fall crop of rye will smother weeds and increase organic matter. You can also establish a low-growing clover as a perennial cover crop in the orchard by sowing its seed with oats as a nursery crop. The oats get mowed before they go to seed, leaving a protective stubble for the young clover.

Optimal soil

The best soils for an apple tree are deep, light in texture, and well-drained, yet able to retain moisture. The soil needs to be deep enough to encourage good root development. Plant on a slope when possible; in winter, the cold air will move downward and protect the tree from the most severe cold damage. In summer, the moving air rapidly dries foliage, minimizing fungal growth and the need for sprays.

Adding minerals

A wide range of minerals can be added to the soil as well. The season prior to planting, spread the nutrients, then mulch with wood chips. The following spring, dig your hole and plant your apple tree. This feeding program also benefits established trees greatly. The minerals should be spread out to the drip line (the outermost reach of the branches). On newly planted or young trees, make a circle at least 2 feet out from the tree trunk.

Some nutrients need to be added directly to the planting hole. Feeder roots grow horizontally, so dig a wide hole deeper than the original growing depth of the tree. As feeder roots are shallow, be sure to mix the added nutrients into the hole at the previous soil level. Use the existing topsoil and subsoil to fill the hole whenever possible.

Calcium, magnesium and phosphorus bind tightly to the soil and do not move readily down from the surface into the major feeder root zone. Surface or top dressings take years to become available to the tree roots. The nutrients are best mixed with the topsoil at planting time, and later top-dressed to prevent future deficiencies. Boron, sulfur and nitrogen are readily assimilated into the soil and can be top-dressed.

Do not add nitrogen directly to the planting hole. Apple trees need very little nitrogen, amounts best attained through gradual downward assimilation from top-dressing. Too much available nitrogen promotes uncontrolled growth, which may not slow in fall and may make the tree prone to winterkill or severe dieback. Barnyard manure can be spread around trees at a rate of 10 pounds per tree.

Planting apple trees

Dig a large hole at least twice as wide and 6 inches deeper than the apple tree’s root system. A larger hole is more beneficial. You can mix a quart of rock phosphate, azomite and a few shovels of compost with the soil. Try to plant on an overcast day or late in the afternoon. Soak the tree in a bucket of water for a few hours before planting and don’t let the roots dry out while planting.

Nestle your apple tree into the hole so that it will grow at the same height it was in the nursery. This may be hard to determine, but usually, the color changes where bark tissue transitions into root tissue. Spread the roots in the hole and don’t let them wrap around the hole. Planting too deep can “choke” the tree by burying bark tissue that should be exposed to the air; it can also disrupt the flow of nutrients from the root system up through the rest of the tree. 

Post-planting

After mixing your soil, fill in around your apple tree. Add water after every 4 inches of soil. Do not heel in the soil, but gently tamp it with your hand. Thoroughly soak the soil, making a retaining rim of soil at the edge of the hole. Water weekly throughout the first year. Refill the hole, making sure no air pockets form around the roots by gently tamping the soil. Build a bowl or rim at the top of your hole that will hold water and then thoroughly soak the soil. Mulch with wood chips.

Plant dwarf and semi-dwarf apple trees with the graft union about 2 inches above the soil; with deeper planting, the wood above the graft may send out roots, turning your dwarf tree into a full-size standard tree.

Shallow planting can expose roots to excess air, even when they’re right under the surface of the soil, causing them to dry out quickly and eventually die.

Caring for your apple trees

Mulching 

Once the apple tree is in the ground, build a small berm of soil around the perimeter where disturbed soil meets the undisturbed, roughly 3 feet in diameter. This helps retain and concentrate water on the young root system. Mulch should extend 4 feet from a young tree and to the drip line of an established tree. It’s also recommended to mound aged wood chips or mulch hay over this berm to help retain soil moisture while suppressing sod and weed growth. Apple trees are typically planted in fields or other open spaces, so it’s important to suppress the sod so that it does not compete with tree roots.

It’s also necessary to keep weeds out of the bare soil in the planting zone, inside the berm, in order to reduce competition. You can easily do this — lightly scratch the ground with a hoe every week or two. A straw or hay mulch reduces weed competition, retains moisture, adds nutrients and increases beneficial microbial action and worm populations. A layer of cardboard beneath the mulch prolongs the weed-free period. 

Mulching is also a great way to build the soil around trees without disturbing what’s going on underground. If you disturb the soil, it can damage roots or even kill a young tree.

Long-term care

Fertilizing

A pH level of 6.5 to 6.8 in the soil is imperative for proper nutrient absorption. Feeding the soil is a long-term process that begins with soil preparation for planting. Foliar sprays can also be utilized to deliver nutrients and boost health. For a simple calendar of monthly organic nutrient and low-spray applications, refer to our apple tree care calendar below.

Pest Prevention

Apple trees in Maine have three main predators: rodents, deer and insects. Here are some solutions on how to protect your trees.

Deer

Deer are a difficult problem. Use a high, woven-wire fence to help alleviate the issue. Electric fencing works well but needs maintenance. Individual trees can also be fenced. This article discusses types of deer fencing and deterrents.

Rodents

Fruit trees also need protection from mice and voles. A wire, screen or plastic collar can offer good protection. They must be applied in the fall and removed in the spring. Apple borer guards double as mouse guards.

Roundheaded apple borer

Roundheaded apple borers are one of the worst enemies of young apple trees. These insects chew and hollow the tree for up to three years. To find the critters, inspect the trunk within the first 18 inches above the ground; you might see a small hole with rusty, chewed sawdust coming out of it — this is a borer hole. Borers can be dug out with a knife or killed by snaking a wire into the hole and piercing them. Even serious carving is less damaging than a borer.

Borers thrive in shady, moist environments and are most active in June and July. Keep tall grass away from tree trunks. Mulch is ideal for this. Homemade borer collars of 1/8-inch hardware cloth or metal screening wrapped around the tree trunk helps with them. It must be 1/8 inch or smaller to exclude adult egg layers. Push the screening 2 to 3 inches down into the soil. Add a top collar of closed-cell pipe insulation to prevent the adult borer from slipping beneath the mesh to lay its eggs, and smear Tangletrap on top of the collar to increase the deterrent. Be sure to loosen the screen as the tree grows. This guard can be left on year-round, doubling as mouse protection in the winter.

Plum curculio

Plum curculio is another pest to worry about. They lay eggs under the skin of apples, and their larvae feed on the fruit. Thus, the apples can’t be eaten nor sold. 

Surround, a kaolin clay product, can be sprayed on trees. It leaves a light-colored residue that irritates insects and works well on a small scale, although repeated spraying will be necessary if rain washes the clay from the trees. Surround works against plum curculio, but it must be applied by petal fall and remain on the trees until about the end of June. You may need to spray trees (trunks, leaves, etc.) a couple of times at first to build up enough of a clay residue.

Another way to limit curculio damage is to cut a slit in a tarp so that you can spread the tarp on the ground beneath a tree. Then shake the tree at least twice, once in the morning and once in the afternoon. The curculios will drop from the trees onto the tarp and “play dead.”

In an existing orchard, remove scabby apples and fallen leaves in the fall or run over the leaves with a lawnmower, or spread compost or lime around the trees to cut down on disease.

Codling moth 

Codling moths, like plum curculio, also bore their way into apples. The caterpillar form of the moth is what is commonly referred to as the worm in an apple. 

They can be trapped by mixing a dollop (or up to a cup) of molasses in a gallon of vinegar and putting a few inches of this solution in the bottom of a soda bottle that has an opening cut from its side. Hang two or three of these soda bottles on each medium-sized tree, close to fruits, from early June through early September, and codling moths will fly into the bottles and drown in the liquid. Remove the moths every week or so.

Pheromone wing traps also work well for monitoring codling moth activity in your orchard when used with a codling moth lure. The lure — the pheromone essence of a female codling moth — attracts males into the trap. When they land, they stick to the bottom of the trap.

The white sticky bottoms of the pheromone wing traps can be replaced if the trap fills with moths — there are a couple of generations of this pest each year — but the lure must be replaced midseason, as the pheromone essence runs out. These traps should be hung before bloom, at eye level for easy inspection. Only one or two are needed per acre.

Apple maggot fy

Apple maggot flies are a type of fruit fly that lay eggs in apples. To trap them, you can remove old apples from your root cellar or buy apples at the store, put wires through them, coat them with Tanglefoot and hang about two of these sticky apples on each tree at eye height. Trim the branches away from this trap so that the flies see it.

Yellow sticky cards can also be used to trap apple maggot fly. The adhesive on these cards contains a food attractant that makes the trap more inviting. This attractant is not found in Tangletrap.

Red ball traps are used in a similar fashion to trap apple maggot flies in midseason and should be hung in trees by July 1 and monitored twice per week. These traps do not come with the sticky substance applied, so you need to coat the spheres: one ounce of Tangletrap should cover three traps. These plastic traps come in reusable and disposable models. The former must be cleaned of flies and coated with new sticky material at least once per season. Trapping can be enhanced in larger plantings by hanging an apple essence lure near the traps, but this does not seem necessary in smaller plantings. Recommendations are one to two traps per dwarf tree, two to four per semi-standard and four to eight per standard.

Apple sawfly

Apple sawflies also lay their eggs in apples, and their larvae feed on the fruit. White sticky cards can be used to trap them. The white of the card mimics the white of the apple blossom, which attracts these pests. When they land, they become stuck. These cards should be hung before bloom at eye level on the south side of the tree where the sunlight is strong and the trap is highly visible.

Maintaining your apple trees all year

Growing an apple tree can take a bit of time, but the payoff is worth it. Think of the pies, crumbles, tarts, jams, butter, or just the first refreshing bite of an apple grown from your orchard.

As a summary, we’ve included a full calendar outlining the tasks involved with growing apple trees. Growing apples organically has its challenges, with various insects and disease, and this calendar can help with understanding pest cycles.  But remember, the best orchard activity is the frequent observation of tree and fruit growth, combined with an awareness of life in your orchard ecosystem.

Apple tree calendar

MarchAprilMayJuneJulyAugust
Prune.
Save scions for grafting.
Remove and destroy mummified fruit and disease cankers.
Plant new trees.
Bench graft and top-work.
Chip prunings for mulch.
Spray dormant oil, if needed.
Train limbs of young trees.
Look for borer sign weekly.
Remove tent caterpillars.
Hang white cards for European apple sawfly.
Hang codling moth (CM) pheromone traps, track degree days (DD) with first male caught.
Apply Surround spray at petal fall, reapply weekly.
Collect and destroy all drops weekly.
Thin fruitlets, remove damaged ones.
Scythe grass and use as mulch.
Apply Bt spray for CM egg hatch at 245 DD.
Stop Surround sprays.
Plum curculio migration ends at 308 DD from petal fall.
Hang red sphere traps for apple maggot fly (AMF).
Place cardboard bands on trunks for pupating CM larvae; destroy and replace every two weeks.
Bud graft.
Summer prune water sprouts and suckers.
Apply Bt or spinosad for AMF and second generation CM at 1260 DD.
Scythe grass and use as mulch.
Harvest first summer apples!
SeptemberOctoberNovemberDecemberJanuary – February
Continue harvest of late summer and early fall varieties.
Continue to collect and destroy drops weekly.
Harvest fall and winter varieties!
Remove limb spreaders and traps.
Apply fish spray, lime and/or compost to hasten leaf breakdown, then rotary mow leaves under trees.Put vole guards in place.
Pull back mulch from trunks.
Remove traps and spreaders from trees.
Root cellars full of fruit!
Visit orchard regularly to check for deer, vole or rabbit damage.
Order supplies.
Maintain tools and equipment.

Now that you know how to grow apple trees, it’s time to start your own orchard.


For orcharding questions, email C.J. Walke at [email protected].


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