Growing blueberries in containers is so easy and effective that you might want to try it even if you have enough in-ground garden space where you can plant this antioxidant-rich fruit. Blueberry plants can thrive and bear fruit in containers in any area that receives full sun. Just be aware that growing blueberry plants in pots (or anywhere else) requires some patience. As with most fruit-bearing species, it can take a few years for plants to produce fruit.
If you've grown other fruit-bearing plants, you know you're in it for the long haul. Your plants can happily produce fruit for years with relatively little care, but you'll want to start them off right. For blueberry plants, that means opting for the largest pot possible, planting one plant per pot. Choose a container that's at least 18 inches deep and boasts ample drainage holes. Half-barrels and other deep, wide containers work well for keeping blueberry plants in for the long term.
Buy Blueberry Plants
When choosing blueberry plants, be aware that they need friends. For them to produce fruit, at least two plants of two different varieties are required for cross-pollination—three plants are even better. Place the pots fairly close together, about 2 to 3 feet apart. It’s also a good idea to grow different varieties of blueberries that produce fruit at different times of the growing season to extend your blueberry harvests.
Moreover, it's important to choose a blueberry species and cultivar that's right for your climate. The four main blueberry species are highbush, lowbush, rabbiteye, and half-high. Within these species, there are many cultivars to choose from. To learn which cultivars will thrive in your area, contact a local farmer or a nursery professional. You may also decide to choose a cultivar based on the desired size of the fruit. Large berries tend to be good for eating, while small berries are usually preferred for cooking things like pies, crisps, and preserves.
Prepare the Soil
Blueberry bushes like very acidic soil, and a pH level between 4.0 to 4.8 is required for the plants to absorb water and nutrients and produce berries. Because most garden soil is not naturally this acidic, planting in containers enables you to better control your soil's acidity levels. You can buy or create an acidic blueberry-friendly potting mix to ensure your plants will thrive
To get started with the right soil mix, fill your pots two-thirds of the way full of regular potting mix, adding a potting mix designed for acid-loving plants (such as rhododendrons, azaleas, and camellias). You can find this mix at most nurseries and garden centers, as well as in the houseplants section of some home centers. If you can't find a high-acid potting mix, add a fertilizer blend designed for acid-loving plants to a third of the soil instead.
If you have trouble finding a commercial potting soil for acid-loving plants, consider using a recipe developed by Cornell University. Mix equal parts peat moss and vermiculite, then add in a granular 11-5-11 fertilizer. Test the mixture's pH level using a soil test kit, and adjust the pH level if necessary by adding limestone to raise the pH or iron sulfate to lower the pH.
An equally effective potting mix uses equal parts garden soil, well-rotted compost, and coarse sand. Test the mixture's pH balance, and add iron sulfate as needed to increase acidity.
Plant the Blueberries
Plant your blueberry bushes into their containers, burying them as deep as they were in their nursery pots. If necessary, top with additional soil, leaving the top inch or so of the container empyt. Immediately water the pot thoroughly to settle the soil and eliminate any air gaps around the plant's roots.
Blueberry plants need a lot of water, but they also like sandy, well-draining soil. In other words, they don't like to be sitting in water, so keep the soil consistently moist, but not soggy.
When it rains, don’t assume that you don’t have to water your plants. The leaves of the blueberry plant can act as an umbrella, preventing water from making it to the base of the plant and into the container. Always check the soil with your finger to see whether it’s wet an inch or two below the surface. If you're not able to water your blueberry plants for a week's time or more, move the plants into a more shaded area to conserve water. It can also be helpful to add a layer of compost with a topdressing of pine bark to retain some moisture.
Maintain the Proper Light
Blueberry plants need six to eight hours of sunlight per day. It's easy to overestimate how much sun an area gets, so it's important to accurately measure the sunlight in your garden. One simple method is to use a watch to time the hours of full-sun exposure on a typical day during the growing season. However, if you live in an area with very hot afternoon sun, be aware that blueberry plants can overheat. They likely will appreciate some light shade during this part of the day.
You may need to move your containers around during the day to ensure the plants get the required amount of sunshine. With big pots, putting the containers on rolling casters makes it easier to follow the sun.
Fertilize Your Plants
Blueberries don’t like too much fertilizer, so a single feeding in the early spring typically works well. Opt for organic fertilizer, like cottonseed meal or a blend specifically designed for acid-loving plants.
Furthermore, don't just fertilize and forget. Test the soil's pH regularly to ensure it is between 4.0 and 4.8. Because acid washes out of soil over time, you may find that it's more effective to start with a half dose of fertilizer in the spring and then add a light monthly dose throughout the growing season.
Watch Out for Issues
Birds love blueberries just as much as people 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. While the process may be cumbersome, it works.
If yellowing of the leaves occurs, it's probably a sign that the soil pH is too high and is causing chlorosis. To rectify the issue, acidify the soil with fertilizer made for acid-loving plants.
Insect and fungal problems can sometimes occur on blueberry plants. If you need to treat your plants, make sure to use a fungicide or pesticide that is safe for edible plants. Blueberry maggots and cherry fruit worms can also be occasional problems. While these pests are treatable with systemic pesticides, be wary of their use, as many are toxic to pollinating insects.
Winterize the Plants
Once your growing season is over, you'll want to protect your blueberry plants for the winter season. Blueberries are tough plants, but if you live in a cold-winter climate you should move your containers against the side of your home 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 the plants are dormant, they don’t need much water, but you shouldn't let them dry out completely.