Growing blueberries in containers are so easy and effective that you might want to try it even if you have enough outdoor garden space for this vitamin- and antioxidant-rich fruit. The plants can thrive and bear fruit in containers in any area that gets a lot of sunlight. Just be aware that growing blueberries in containers (or anywhere else) requires some patience. As with most fruit-bearing plants, it can take a couple of years for the plants to produce a lot of fruit.
Choosing Containers and Plants
If you've grown other fruit-bearing plants, you know that you're in it for the long haul. Your plants can happily produce fruit for years with very little care, but you'll want to start them off right. That means putting them in the largest pot that you can. Pick one at least 18 inches deep. Half-barrels and other deep, wide containers work well for the long-term.
When choosing plants, blueberries need friends. To get your blueberries to fruit, you will need at least two blueberry plants for pollination, and three plants are even better. Place your blueberries fairly close together. It’s also a good idea to grow a couple of different varieties of blueberries that produce fruit at different times to extend your blueberry season.
Choose a plant variety that's right for your climate. There are four main types of blueberries: highbush, lowbush, rabbiteye, and half-high. Within these types, there are many more varieties to choose from. Ask a local farmer or favorite nursery to learn what will thrive in your area. You might also choose a variety based on the desired size of the fruit. Large berries tend to be good for eating, while smaller berries are usually preferred for cooking.
Acidifying Your Soil
Blueberries require acidic soil. Most need soil with a pH of 4.5 to 5.5 to thrive and produce berries. Since most garden soil doesn't come close to these levels naturally, this is one of the main advantages of growing blueberries in containers. You can easily buy or create an acidic blueberry-friendly potting soil to ensure your plants will thrive.
To get started with the right soil mix, fill your pot 2/3 full of your regular potting mix and the top third with a potting mix designed for acid-loving plants, like rhododendrons, azaleas, and camellias. You can find this at any nursery or garden center or the houseplants section of some home centers. If you can't find a high-acid potting soil, you can mix in fertilizer for acid-loving plants into your soil, such as Holly-Tone, by Epsoma.
The Right Amount of Sun
Blueberries need full sun, as in a full 6 to 8 hours per day. It's easy to overestimate how much sun an area gets, so unless you are absolutely positive about it, take the time to accurately measure how much sun your plants are getting. Use a sun calculator, or simply use a watch and time the hours of full-sun exposure on a typical day during the growing season. On the flip side, If you live in an area that gets very hot afternoon sun, be aware that the plants can overheat.
Watering Your Plants
Blueberries need lots of water, but they also like sandy, well-draining soil. In other words, they don't like to be sitting in water, so try to keep the soil consistently moist, not soggy. When it rains, don’t assume that you don’t have to water. The leaves of the blueberry plant can act as an umbrella, shedding the water so that it misses the container completely. Always check the soil with your finger to see if it’s wet below the surface. If you have to leave your blueberry plant and can't water it, make sure to move it to the shade to conserve water. It's also helpful to add a layer of compost with a topdressing of pine bark to help conserve water.
Blueberries don’t like too much fertilizer. Fertilizing twice a year in the early spring works well. For organic fertilizer, try blood or cottonseed meal or an organic fertilizer designed for acid-loving plants. Don't just fertilize and forget. Test the soil's pH regularly to keep the soil in the sweet spot for acid. Because acid washes out of the soil over time, you might find that it's more effective to start with a half-dose of fertilizer in the spring, then add a light monthly dose throughout the season.
Birds love blueberries just as much as we do. The best way to protect your fruit from feathered poachers is to surround your bushes with bird netting a few weeks before the berries are ripe. Bird netting may be a pain, but it works.
Winterize Your Plants
When the growing season is over, protect your plants for the winter ahead. Blueberries are tough plants, but if you live in a cold-winter climate, move your containers against a building or into a protected area to keep them out of the wind. You can also mulch your plants with straw or wrap them in burlap. In the winter, while plants are dormant, they don’t need much water, but don’t let them dry out completely.