Almost everyone has a favorite apple memory, whether it’s bobbing for apples at Halloween, eating a wonderful apple pie, or picking apples on a crisp fall day. If you have a little space on your property that gets at least seven hours of sunlight a day, you can grow your own apples. 

Talk to the Napa County Master Gardeners or to a local nursery staffer about the types of apples that grow well in your area. Like most fruit trees, apple trees require limited but regular care to stay healthy and produce well. The payoff for a little work is terrific: many, many years of fresh, flavorful fruit. While the harvest is over for this year, we now begin a new year of tree care. 

Apple tree maintenance consists of five components: watering, pruning, fertilizing, managing pests and fruit thinning. Let’s start with pruning. 

Pruning in the winter invigorates the tree; pruning in early summer controls the size of the tree. In the fall, start pruning once the tree has dropped all its leaves. Cut out any broken and diseased branches, then focus on creating a balanced structure. You want air to circulate through the branches and light to reach the interior of the tree. 

Remember to sanitize your pruning tools between cuts and between trees to avoid spreading disease. You can prune up to 30 percent of the total leaf mass each year. Your tree will thank you by producing better fruit

Fruit trees also need regular water. Start watering in the spring when the grass in the hills starts to turn yellow. Stop after we’ve had our first soaking rain in the fall. Water established trees about once a month; a periodic slow, deep soaking is better than frequent shallow watering. You may need to water a little more if we have a hot, dry spell, as we did several times this year. 

Young fruit trees benefit from watering twice per month. Remember to increase the amount of water you give your tree as it gets bigger. While a 1-year-old tree might only use two gallons of water on a hot summer day, a mature tree can use 25 times that much. Adjust your watering during the season; plants use only 40 percent as much water in mid-spring and early fall as in mid-summer.

Mulch your trees to conserve soil moisture and keep the root zone cool. You can use compost and other organic materials as mulch; all add some important micronutrients to the soil. A four-inch layer of mulch will also help smother weeds. Trees grow better and produce better fruit when weeds are controlled. Keep mulches and irrigation water at least three inches away from the trunk of the tree to prevent crown rot. 

In general, apple trees are vigorous and need less fertilizer than stone fruits (peaches, nectarines, plums and cherries). Apply fertilizer in the spring and again in mid-summer; for application rates, follow the directions on the fertilizer package. Always water well before and after applying fertilizer, especially if you are using inorganic (chemical) fertilizers. 

In the Napa Valley area, apple trees are susceptible to several pests, including scale, wooly apple aphid, coddling moth and fire blight. To minimize the spread of pests and diseases, always remove dead leaves and fruit around the tree. Control scale and aphid eggs with dormant oil spray; apply it in late fall and again in early spring, before the tree leafs out again. 

Coddling moth is difficult to banish but pheromone traps, sticky traps, summer oil sprays and commercial insecticides provide some control. Coddling moths produce several generations a year, so to reduce damage to your apples, you have to battle them continually.

Fire blight is a bacterial disease with no cure. You can tell a branch is infected if the shoots and fruit suddenly wilt, shrivel or turn brown. If you see signs of fire blight, cut the branch off 12 inches below the infected area.

And did I say “fruit thinning?” Most fruit trees, including apples, set much more fruit than they can support. If you take no action, the mature fruits will be too small and the tree may fall into a cycle of bearing only in alternate years. Overloaded branches are also prone to breaking. Before the baby apples reach one inch in diameter, thin the fruit to six inches apart.

 If you have further questions about caring for apples or other fruit trees, consult the Napa County Master Gardeners during office hours or e-mail your questions (instructions below).    

 Napa County Master Gardeners,  http://cenapa.ucdavis.edu, answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to noon, at the UC Cooperative Extension office, 1710 Soscol Ave., Suite 4, Napa, 253-4221, or toll-free at (877) 279-3065.