Everything You Need to Know About Growing Fruit Indoors

You don't have to live in the tropics to grow fruits such as lemons, oranges, grapefruits, passion fruit, and figs. By growing fruits indoors in containers, you have the opportunity to move plants to a sheltered spot for the winter and work around problems such as poor soil.

You can grow fruits in a greenhouse, in a cool basement, or on a sunny windowsill. Many of these plants need pampering and more effort than the average houseplant, so follow these tips, and you'll be on your way to having fresh fruit grown in your home.

Container Fruit Gardening

Before selecting a container for growing fruit indoors, consider your needs. Think about size, durability, and weight. Smaller plants can grow for a couple of years in a traditional 8-inch-wide fruit container; larger varieties may need to be moved to larger containers until they're in 36- or 48-inch-wide pots. Keep in mind that the bigger the fruit container, the harder it is to move.

There are many options for fruit containers, along with some advantages and disadvantages to every choice. Terra cotta, stone, and ceramic fruit containers are durable but heavy. Wood fruit containers are attractive and generally lightweight but can rot over time.

Fruit containers are also available in synthetic materials such as plastic, polystyrene, and other modern composites. These are lightweight, long-lasting, and fabricated to resemble many kinds of materials. Make sure the container you choose has drainage holes.

Choosing a Potting Mix

Fruit containers allow you to provide the perfect soil—a combination of optimal aeration and drainage with good moisture retention and the ability to hold nutrients. Unfortunately, garden soils won't cut it in a container. They rarely drain correctly, are usually too heavy, and often contain disease organisms.

There are many potting mixes formulated explicitly for growing fruits in containers. Many of these contain no actual soil at all. Consider using a blend with moisture-control amendments and controlled-release fertilizer to reduce watering and feeding frequency.

You can also whip up your own potting mix. For 1 cubic yard, take equal parts peat moss or composted fir or pine bark and mix in perlite, dampening the mixture as you go. If you wish, add a slow-release fertilizer to the mix. Combine by scooping the ingredients into a cone-shaped pile, letting each shovelful slide down the cone. To get a thoroughly mixed product, repeat the cone-building three to five times.

Watering and Fertilizing

Subtropical fruits grown in containers require more frequent watering than those grown in the ground. Make sure to use enough water to soak the entire root ball. Watch for moisture that comes out of the pot when you water. If it seems to rush out of the drainage holes, your plant has gone too long without water, and the potting mix is shedding moisture instead of absorbing it. Slowly add small amounts of water to help the potting mix grab the water.

Feed plants at least once a month with a complete liquid fertilizer containing micronutrients to compensate for nutrients lost from watering. Many gardeners feed weekly in hot-summer areas where watering is a constant chore. Start feeding in early spring and stop in late summer or early fall to avoid encouraging late growth in frost-prone seasons.

Granular fertilizers can also be used on container plants, but they need time to dissolve before nutrients become available to the roots. A slow-release fertilizer provides nutrients over time, from weeks to months, depending on the product. It can help maintain a steady supply, but you may need to supplement with liquid fertilizer during peak growth.

Root Pruning

When growing fruit indoors, your plants will sooner or later run out of root space—even those well adapted to containers. Without root space, the dense root ball becomes harder to water, causing stunted growth and delayed fruit production.

Although it may seem drastic, pruning the roots isn't as hard as it sounds:

1. Prune the top of the plant by at least one-third to compensate for the roots you are about to prune.
2. Remove the plant from the container.
3. Cut off one-fourth to one-third (no more than 2 to 3 inches, depending on the size of the pot) of the outside root ball with a sharp knife.
4. Place the plant back in the pot with fresh soil and water thoroughly.

This can be the easiest way to help a root-bound indoor fruit plant.

Transition from Indoors to Out

If you keep your subtropical fruit plants and trees outside during the warm months and inside during the winter, you'll need to acclimate your plants to the new environment. Do it gradually if you're putting plants outside after a long winter indoors. Place them in a shady spot first, then slowly expose the plants to increasing amounts of sun over several weeks to help prevent sunburned foliage.

Move fruit plants from outdoors to indoors at an equally slow pace. Give them less and less sun until they're ready to come inside. Before bringing a fruit plant indoors, hose it down to wash off dust or dirt on the leaves. If necessary, spray to control pests, which will multiply when brought indoors.

Adjust Care

Once the fruit plants and trees are indoors, they won't need as much water—but don't allow them to dry out completely. They also won't need much light if you're trying to keep them cool and dormant until spring. But if you are trying to ripen the indoor fruit plants, the more light, the better. Consider supplemental illumination with artificial lights. Adjust the feeding according to how you want the plant to grow, but generally, feed lightly.

The dry heat that circulates through most homes during the cold months shocks fruit plants that have been outside all summer and may cause them to lose their leaves. Do everything possible to increase the humidity around the fruit plants. For example, you can place the containers on a tray of rocks partially submerged in water or group the indoor fruit plants away from heat vents.