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. Growing them in pots is the answer, however, if you want to grow blueberries but your soil isn't optimal for producing the 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.
|Common Name||Blueberry bush, rabbitteye, lowbush, highbush|
|Plant Type||Perennial shrub|
|Size||24 in. to 4 ft., depending on variety|
|Sun Exposure||Full sun|
|Soil Type||Sandy and well-drained|
|Soil pH||Acidic (4.0-4.8)|
|Hardiness Zones||3-10 (USDA), depending on variety|
|Native Area||North America, South America, Europe, Asia|
How to Plant Blueberries in Containers
When to Plant
Plant blueberries in containers in the spring or late fall in most areas. In the coldest zones, wait to plant the bushes in containers until early to mid-spring.
Selecting a Planting Site
Luckily, 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.
Spacing, Depth, and Support
You'll have more than one container of blueberries in order to pollinate, but replicate the spacing, depth, and support for all of them. Plant one blueberry bush per pot. Put it into its container, burying it as deep as it was in its nursery pot. If necessary, top with additional soil, leaving the top inch or so of the container empty. Immediately water the pot thoroughly to settle the soil and eliminate any air gaps around the plant's roots. The bushes will not need support to grow.
Blueberries in Containers Care
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.
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 hot afternoon sun, be aware that blueberry plants can overheat. They likely will appreciate some light shade during this part of the day.
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 soil's pH level using a 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.
Blueberry plants have shallow roots that dry out fast so they 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. Potted blueberry bushes like 1 to 2 inches of water a week.
If you're not able to water your blueberry plants for a week 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.
Temperature and Humidity
Containers of blueberries need to be placed in a sheltered spot between December and March when winter winds are at their worst. Blueberries do not like overly dry conditions, and that includes dry winds in addition to cold winds.
Consider the important chill factor, or chill hours, when planting blueberries in containers. Every cultivar has a different chill factor requirement. A chill hour is time when the temperature outside stays between 32 and 45 degrees Fahrenheit.
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 the 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.
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.
Most important, choose two to three varieties of blueberries that bloom at exactly the same time or overlap so that bees can easily cross-pollinate the plants. Choose varieties within the species, however. You can't cross-pollinate a variety of rabbiteye with a variety of highbush, for example.
Types of Blueberries
Moreover, it's important to choose a blueberry species and cultivar that's right for your climate. The four main blueberry species (highbush is one species divided into northern and southern) and a few of their popular cultivars include:
- Northern highbush (Vaccinium corymbosum): Most popular and most productive blueberry shrub for cold areas; Popular cultivars include 'Bluecrop,' 'Blueray,' 'Herbert,' 'Jersey,' 'Meader,' 'Berkley,' 'Coville,' and 'Darrow.'
- Southern highbush (hybrid Vaccinium corymbosum and Vaccinium darrowii): Grows in the south 6 to 8 feet high; Popular cultivars include 'Golf Coast,' 'Misty,' and 'Ozarkblue.'
- Lowbush (Vaccinium angustifolium): Best for cold climates, native to the northeast U.S. and known as wild blueberries; There are no named cultivars of lowbush.
- Rabbiteye (Vaccinium virgatum): The bush grows to 15 feet tall and is mostly grown in the south; Popular cultivars include ‘Powderblue', ‘Woodard', ‘Brightwell', 'Pink Lemonade,' and 'Delite.'
- Half-high: A newer hybrid of highbush and lowbush and a bit less sweet; Popular cultivars include 'North Country', ''Northblue', 'Northland,' and 'Top Hat,' which was bred to be especially ideal for container growing.
There are more cultivars within the species. To learn which ones will thrive in your area, contact a local farmer or a nursery professional. You may also decide to choose a variety based on the desired size of the fruit. Larger specimens are great for eating berries from the bush, while small berries are usually preferred for cooking things like pies, crisps, and preserves.
Blueberries vs. Bilberries
Blueberries and bilberries look nearly identical, they are both edible, and they are related, as well. Bilberries, sometimes called European blueberries, are smaller than blueberries and dark blue to nearly black. You will rarely find a bilberry bush elsewhere other than in the woodland wilds of Northern California and Pacific Northwest. A raw bilberry will taste tart and acidic with a hint of sweetness, almost like a sour cherry.
Harvesting Blueberries in Containers
It's most likely you won't have to harvest blueberries within the first year of planting blueberries in your containers. You should expect to be able to harvest a full crop of potted blueberries in five years. Pick them between June and August, but they should be easy to harvest as they fall off the bush and right into your hand.
How to Grow Blueberries in Pots
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. For even better drainage, place pots on top of bricks. Wooden half-barrels and other deep, wide weatherproof containers work well for keeping blueberry plants in for the long term.
Blueberry bushes can grow large, but they won't need pruning until their fourth year in the pot. The pruning will stimulate more growth. Prune the bushes before it begins its new growth phase. Use sterilized, sharp garden tools to cut dead, weak, low-growing, and unruly branches in the late winter or early spring. Pruning thins out the old growth, allowing light into the middle of the bush.
Growing blueberries in containers may be so much fun that you may want to propagate a plant to continue growing in pots or in the ground. This woody shrub is easily propagated by rooting cuttings. Take softwood cuttings (may wilt faster because it's from fresh new growth) in the early spring and hardwood cuttings (firmer and more mature) in the late winter. Do propagate with cuttings, take these steps:
- With a sharp, sterilized garden cutting tool, remove the last 5 inches of growth from a healthy branch.
- Remove most of the leaves from the branch, leaving the top two or three leaves. Dip the cut bottom of the branch in rooting hormone.
- Set the cutting in moist soilless potting mix in a small pot that is then placed in a consistently warm space.
- The pot should stay in bright but indirect light and the soil should stay moist but not waterlogged.
- New leaves should grow in a few months and the roots should be settling in enough to transplant the seedling to a larger pot.
Growing Blueberries From Seeds
Blueberry seeds are hidden inside the fruit and need coaxing to separate them from the interior pulp. You can grab seeds from existing fruit or buy them in order to start your container garden. Just make sure you are buying or taking seeds from pollinating varieties. You will want to start the process in the fall in warm regions and the spring in cool climates. Once you have the seeds, take these steps:
- Put the seeds in the freezer for 90 days.
- Take them out of the freezer. Use a flat tray filled with moist sphagnum moss. Sprinkle the seeds on the moss and lightly cover them with more moss.
- Cover the tray with newspaper.
- Put the tray in an area that consistently stays between 60 and 70 degrees Fahrenheit.
- Keep the moss consistently moist and you will see seedlings in about a month.
- Remove the newspaper but keep the tray in bright, indirect light until the seedlings are a few inches tall.
- Plant seedlings in a moist mix of peat moss, sand, and soil until they can be placed in larger containers.
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.
Common Pests and Plant Diseases
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.
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.
Do blueberry bushes produce flowers?
Yes, blueberry bushes do produce flowers, but they are not for enjoyment. To ensure that your container bushes do well, you will want to remove the blooms for the first two years the bush is in the pot. That will allow the plant to grow and fruit vigorously. You do not need to remove the flowers from the plant in the third year, however, but they are not showy.
Are there any self-pollinating blueberries?
The northern highbush species is thought to be self-pollinating, but the yield will be small, or possibly no berries. It's always best to plant for cross-pollination for an abundant and juicier harvest.
Can blueberries be planted in a hanging planter?
Many people who don't have room for pots on balconies or in other small spaces do use dwarf blueberry bushes in hanging planters. In that case, you'll want to find a cultivar that has more of a trailing growth habit, such as the 'Midnight Cascade' which grows up to 2 feet tall and wide.
What is the difference between low chill hours and high chill hours?
A cultivar that needs 450 chill hours, such as the 'Midnight Cascade,' is considered to have low chill hours. A cultivar like rabbiteye's 'TifBlu' requires between 600 to 800 chill hours and is considered to need high chill hours.