By Urban Harvest
What fruits can be grown in containers? The truthful answer is that all fruits can be grown in containers. Not all of them will be happy in containers for the long term, but many will grow happily in a container for all, or at least part, of their lives.
Growing fruits in containers presents some unique opportunities. The concept is not new. Fruit has been grown in containers for hundreds of years. It is a bit different than growing in the ground, and there are some cultural techniques that must be paid attention to, but there are actually a few advantages.
We can more easily influence pH, nutrition, moisture, aeration and drainage. Access for pruning and harvesting is easy in containers. Containers provide an opportunity to add a level of design through the shape, color, and texture of the container itself. One of the more interesting advantages is the opportunity to examine the root ball during repotting and the ability to stimulate feeder root development through timely root pruning.
Portability is a distinct advantage. We can rotate the plant for even light exposure in marginal locations, arrange trees for improved pollination, and relocate trees to take advantage of beneficial microclimates. Spring flowering fruits can be moved to high visibility areas prior to peak bloom and fruiting, but can spend their fall and winter in a less conspicuous spot in the yard.
Portability gives us several options for winter protection when necessary – from as little as a frost blanket to as much as moving the entire container to a greenhouse when severe conditions threaten.
If your containers will be located on a patio or in a dooryard, you may want to consider fruits that have a high ornamental value – blueberries, pomegranates, kumquats, lemons, limes, and some tropicals such as the “condo” mangoes, dwarf bananas and pineapples.
Some fruits, such as peaches and nectarines, should be considered short-lived in containers and be replaced occasionally. They will produce well enough for several years to offset the cost of replacement. Most fruits can be container grown for several years, then be transitioned to in-ground planting. This is a good method for those who want to get a head start while they are developing a garden or seeking their permanent orchard space. Young avocados will actually perform better when grown in containers for their first three to five years, or until their trunks have developed true bark for 12 inches to 18 inches above the root flare.
The container itself becomes one of our tools in controlling vigor. It will create an artificial “competition” that we can use to our advantage, while still producing modest quantities of fruits for our table and pantry.
The shape of the container has almost as much influence as the overall size. Low and wide is often better than tall and narrow. A 10 inch to 15 inch container (or three to seven gallons) is good to start with. Step up to a 16 inch wide (or 10 gallon), and plan on 17-20 inches (or 15 to 20 gallons) long term. These are generous containers. In the 1850s, a wide variety of fruits were grown in glass houses in 7 inch pots!
The composition of the container must meet your budget and aesthetic. You can use plastic, terracotta, glazed clay, fiberglass or composition materials. Make sure the container has sufficient drainage holes. Many do not and I find myself adding four to six holes in most of the containers I use for fruits. This is not difficult to do with a good drill. Use a masonry bit for terracotta, and drill slowly.
Media for container-grown fruit is critically important. It should be living soil and should provide all of the minerals and nutrients required for tree health and fruit quality. Use a peat-free, compost-based media that is amended with expanded shale, rock minerals, and microbial food. It should retain moisture, but provide both drainage and aeration. It must support the development of both anchor and feeder roots. Specialty soils are available for acid-loving fruits such as blueberries and miracle fruit.
Planting in containers can be easier than planting in the ground, but care must be taken to ensure long-term success and to eliminate potential problems. Check the container-grown tree to locate the root flare. Pull away any nursery soil that covers the tree too deeply.
Partially fill your container with media and tamp firmly, but do not pack hard. You do not want the tree to settle, but you also do not want to compact the soil. Set the root ball on this soil base and fill around the root ball, tamping as you go. Stake the newly planted tree only until anchor roots have established.
Plant the fruit at a depth that allows sufficient head space for watering and mulching. I mulch my container grown fruits for the same reasons we mulch in the ground – weed suppression, moisture retention and temperature moderation. I find that it also discourages squirrels from digging in the media to plant acorns and pecans.
Pruning is similar to in-ground culture with the exception that you may want to limit overall tree height. Container grown fruits are often very attractive when pruned to a pyramidal shape.
Keep the media evenly moist, but never soggy. Drip irrigation is the preferred way to water container-grown fruits. It is easy to install and can be managed by a battery-operated timer.
Begin fertilizing when new growth appears. You will use less fertilizer per application, but should apply it more frequently. Inspect the root ball annually. If the roots are spiraling or if the tree has become root bound, root prune and repot. Vigorous trees will require annual repotting, but most fruits will only need biennial repotting.
You will find many varieties that grow well in our southeast Texas climate of citrus, figs, bananas, persimmon, apples, berries and much more, at Urban Harvest’s 18th annual Fruit Tree Sale fundraiser on Saturday, Jan. 13.
This article is provided by Urban Harvest, Inc. To learn about gardening classes, farmers markets, school and community gardens and more go to www.urbanharvest.org or call 713-880-5540 for more information. This article was written by Angela Chandler, who is a freelance garden writer, speaker and teacher of many gardening classes for Urban Harvest.