Idaho Landscapes & Gardens - FRUIT, VEGETABLES, & HERBS

Watering

When it comes time to plant a fruit tree, patience pays for itself many times over. Most of the problems we see with tree fruits come from two sources: failing to select appropriate crops for a site and failing to prepare the site before planting. We dealt with crop selection in the previous section. Now let's consider site preparation.

Soil Drainage - Poor soil drainage is a very common cause of problems in a home orchard. Fruit trees on wet soils often fail to thrive, growing slowly, and eventually succumbing to root diseases. Peaches and other stone fruits are especially prone to problems on poorly drained sites.

Gardeners often add compost or other organic matter to heavy soils to improve drainage. In reality, most organic materials have high water-holding capacities and increase drainage problems when added to already heavy soils. Likewise, adding sand to soils on a low-lying site does nothing to improve drainage unless there is a way for water to drain away from the site.

Drainage tiles (buried pipes with holes along the sides) can be used to drain excess water away from a planting site, provided you have a lower-lying area for the water to drain to. For one or a few trees, raised planting beds twelve inches or more high can significantly improve drainage, particularly when heavy native soils are amended with sand or a lighter-textured soil is brought in to create the beds. For a fruit tree, a bed ten feet in diameter should suffice. The beds can be contained within walls or sloped from the centers outward. Apples and pears on dwarfing rootstocks and peach genetic dwarfs have been successfully grown in large (approximately 20 to 50 gallon) containers. Container culture requires great care to ensure adequate irrigation and fertilization, and to prevent girdling roots.

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Amending Your Soil - Gardeners like to improve their soils, and often do so by adding composts, manures, straw, sawdust, or other organic materials. There are both benefits and risks associated with soil amendments. Perhaps the greatest advantages to organic soil amendments are that they can increase water and nutrient holding capacities on light-textured soils and can be sources of plant nutrients.

Amendments also carry risks. Weeds, pests, and diseases can easily be brought into your garden through contaminated organic materials. Woody materials, such as straw, bark, and sawdust, can create severe nitrogen deficiencies in the soil as they decompose. Woody materials are broken down by microorganisms in the soil. These microorganisms take nitrogen from the soil to use for proteins and other compounds in their bodies. Until the woody material is decomposed and the microorganisms die, the nitrogen is unavailable to plants. An excellent strategy to avoid importing weeds, pests, and diseases and to avoid depleting your soil nitrogen is to thoroughly compost organic amendments before adding them to your garden. To learn more about composting, click here.

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Planting Your Trees - When planting a fruit tree, dig a hole large enough to hold all of the roots without cutting any of them off and without bending the roots to fit into the hole. A good strategy is to dig the hole, then build a pyramid-shaped mound in the center of the hole and drape the roots over the mound. Be very careful to ensure that, after the soil has settled, the tree is at the same depth it grew in the nursery. Planting trees too deeply often results in collar and root rot and tree death. Also avoid planting too shallowly, which creates an unstable tree and exposes the collar and roots to excessive drying.

Most fruit trees are sold bare root or may come in pots up to about five gallons in size. Plant bare root trees as described above. Container-grown trees are planted similarly, but take particular care to inspect the root ball after the pot is removed and before planting. Use sharp pruning shears to cut through roots that circle around the root ball or cluster on the bottom of the ball. These could result in eventual girdling of the trunk. Be careful not to drop the tree, twist the trunk or root ball, or break open the root ball. Doing so can break off small feeder roots. Always lift trees from the bottoms of the root balls. Never lift a tree and pot or tree and root ball by the trunk.

A simple rule is that the only soil that goes back into a planting hole is the soil that came out of it. Never replace the soil with compost, peat moss, or potting soil. Never create a blend of soil and compost to fill a planting hole. Doing so creates a barrier at the sides and bottom of the hole that makes it very difficult for water or roots to penetrate to the soil outside the planting hole. Essentially, you create a pot without a hole in the bottom. If you want to amend the soil, before digging, apply up to six inches of amendment and till it into the soil across a five- to ten-foot diameter area centered where the planting hole will be.

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Staking and Trellises - Most fruit trees should not require staking when they are planted. As long as a tree remains upright, staking is usually not recommended for free-standing trees. Trunk strength develops as a tree sways in the wind and staking can actually create weak trunks that will not support crop loads. For special production systems, young apple trees can be trained to vertical poles for several years. The slender spindle production system is one example. Apples on dwarfing rootstocks are also sometimes grown on supporting trellis wires. For more information on training systems, refer to Training and Pruning Your Home Orchard.

Fertilization - Assuming you have normally fertile soils, fruit trees are not usually fertilized at the time of planting or during the first growing season. A soil test is your best resource in determining this and helping you to spot trends in fertility over time. Some Idaho soils, however, are deficient in available phosphorus. You can safely add a cupful of steamed bone meal or 0-45-0 fertilizer to the bottom of a planting hole, mix it with a handful of soil, and plant your tree in the hole. Never add fertilizers containing nitrogen, potassium, or boron to planting holes.

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Watering - Ensure that the soil around the tree does not become dry, but avoid overwatering. Your goal should be to keep the soil moist, but not waterlogged. Some gardeners like to build a shallow saucer around newly-planted trees by creating a raised lip of soil about 12 to 24 inches in diameter. This practice can be helpful on soils that drain well until the tree becomes established. On heavier-textured soils, building such saucers can cause problems with the trees. As a general rule, if you build a tree saucer and fill it with water, the water should have drained completely away within an hour or so. If not, remove the saucer. Check newly-planted trees twice weekly to ensure proper irrigation.

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