Blueberries are a fruit that can be grown even in small spaces, and in many regions of the country. The keys to success are picking an appropriate variety for your climate and providing the basic growing conditions blueberries need: acid soil, lots of sunshine, and plenty of water. They’re tasty and ornamental, and look great in large pots on the patio as well as the perennial bed.

Picking a variety suited to your climate

The blueberries we cultivate are not all the same species, but they are all in the genus Vaccinium. Seeds ‘n Such carries northern highbush and rabbiteye types. The northern highbush blueberry, Vaccinium corymbosum, is native to the Northeast and upper Midwest states and needs the cold, while rabbiteye blueberry plants, Vaccinium virgatum, are native to the South and do well in the heat. Groundcover or lowbush blueberries (Vaccinium angustifolium) are native to the northern states and Canada, and are members of the same genus, but are less often grown at home for fruit, although they are common in Maine, the blueberry state.

The important point for gardeners is their cold hardiness and the number of chilling hours blueberries need to bear fruit. Northern highbush varieties are typically cold-hardy in USDA zones 4-7 or 4-8, depending on the variety. Rabbiteye blueberries are cold-hardy in USDA zones 7-9. If you are a gardener in zone 6 or cooler, you’ll need to choose a northern highbush variety. Southern gardeners will need to select a variety adapted to the heat.

Other characteristics include fruit size and flavor, mature plant size, autumn color, and young plant size (1 or 2-year-old plants). Smaller plants are less expensive. Older plants may fruit sooner. 

Of note, while northern highbush varieties are self-fruitful, meaning a single plant will set fruit without a second variety to pollinate it, rabbiteye types need a nearby rabbiteye blueberry of a different variety to cross-pollinate with. For example, planting a ‘Tifblue’ and a ‘Climax’ would ensure both will set fruit. 

Northern highbush blueberries don’t need a pollinator buddy, but they will set a heavier fruit crop if they have a blueberry of a different variety nearby. For either type, a cross-pollinator plant should have an overlapping bloom time and be within about fifty feet of each other for best results.

What about the chill requirement?

Blueberries need a period of cold weather to complete their annual cycle and trigger the changes that lead to blooming and fruiting. If they don’t get the number of chill hours they need, they may fruit poorly or not at all. Chill hours are temperatures above freezing, about 35-45℉, like your refrigerator. They are cumulative and add up from when the plant goes dormant in the fall until spring. 

Northern highbush varieties typically need 800-1000 chill hours, sometimes more. Rabbiteye varieties normally need 300-700. A rabbiteye blueberry planted up north will be killed by the extreme cold, and a northern highbush blueberry bush in the warmer South won’t get enough chill hours to bear fruit. 

The soil pH is important!

Blueberries are famous for loving acidic soil. Any soil measuring below a pH of 7.0 is technically acidic, but blueberries like it much more sour than most other plants. While our gardens do well with a pH of 6-7, blueberries need soil with a pH of 4.5-5.5. Many soils are not that acidic and will need to be amended for proper blueberry growth.

Before planting your blueberry in the ground, test the soil pH with a kit or pH tester, or submit a soil test to your state’s Extension office. Typically, elemental sulfur (buy it at any good garden center) is used to adjust pH and bring the acidity into the range for blueberries. Amending with peat moss and pine bark can help to keep the soil in the right acidity range for blueberries once you’ve got it there. Pine needle and pine bark mulches, while excellent for blueberries and very attractive, don’t appreciably lower the pH of the soil beneath.

You’ll need to test and, if needed, adjust the pH of your blueberries’ soil yearly, especially in containers. The water we irrigate with, whether from municipal pipes or a well, is typically much closer to neutral and can even be slightly alkaline. Repeated waterings will bring the soil back toward a neutral pH. If your blueberry leaves are looking dark purple or red in the middle of the growing season (not in autumn), it might be that the pH is too high.

Spacing blueberry plants

Blueberry plants come in all sizes, so the spacing will vary. But keep in mind that a crowded blueberry plant will struggle and produce less fruit. For ease of picking, access to all sides of the bush is important. Northern highbush varieties can get large, so space them 4-5 feet apart, in rows 8-10 feet apart. Any closer, and you might have a blueberry forest instead of a couple of neat rows you can walk between.

Rabbiteye varieties can grow larger yet, and need 5-7 feet between plants and 10-12 feet between rows.

Run the irrigation lines after planting, and then add the mulch right over the top of the lines. Mulch not only keeps the soil moist, but also prevents a mess of grass and weeds from competing with your blueberry plants.

Shallow roots (need water)

Blueberry plants have shallow, spreading root systems, but they love moist soil. It can create a problem because during dry spells, they won’t be able to reach down and find water. A lack of water will slow their growth, and they won’t produce as much fruit. 

Start by adding compost to the soil when you plant blueberries. Compost helps to hold soil moisture (and of course is beneficial for the soil microbial life and provides nutrients for the plants), and will even out soil moisture swings. One blueberry plant in a container can be watered by hand, but if you are planning a row of blueberries, use a drip irrigation system and place it underneath the mulch. You’ll save water, the moisture will be right where the plants need it, and it will be easy to use. 

Outsmarting the birds

When your blueberry plants start fruiting, it’s time to celebrate. Unfortunately, the birds share this view. While scarecrows or hanging a flashing old CD may work short-term, the only real way to protect your berries is with netting designed to protect fruit crops from birds. String it well, or they can still reach through and grab a blueberry. 

If you can, arrange the netting so you can easily move it to harvest, as you’ll be picking blueberries every few days for several weeks. After you’ve gathered the fruit, or as much as you want, remove the netting so it doesn’t get tangled.

Growing Blueberries In Containers

Happily, blueberries can do well in large containers. For those with small gardens or only a backyard deck or patio, a blueberry bush in a pot can be ornamental and provide a sizeable harvest of tasty berries. 

• You’ll need a large pot. Start with a container at least 12 inches in diameter for a young plant and pot it up in size as the shrub grows. Half-barrel planters can hold one modest-sized mature blueberry plant.

• Pay close attention to drainage. While blueberries like moist soil, they don’t want to be waterlogged. Mixing shredded pine bark and peat moss into the potting mix will help keep the media loose and airy while still holding moisture. 

• Test pH and amend as necessary. Most potting mixes are neutral to slightly acidic.

• Don’t overfill the pot with soil and bark. Leave about two inches at the top so you have room for mulch and to allow room for watering without it flowing over the sides and making a mess.

• Refill the pot from the bottom every year or two. The materials in the potting mix will decompose, and you’ll notice the soil level dropping. Don’t just dump more on top. Lift the plant free of the pot, add more mix to the bottom, and then replace it, and tuck soil around the sides if there are gaps.