A lot of people have become much more interested in growing their own blueberries recently, especially as food trends lean toward organic, healthy, and wholesome food.
But growing blueberries is not something you should do on a whim. If you want them to survive and produce well, there’s a few things you need to know and do.
The most important thing you’ll need to do is to select a site on your property that suit the needs of your blueberries as much as possible, and then make any necessary amendments. It’s also important to choose a variety that will most likely do well in your area in the first place.
PLANNING AND PREPARING
Water: Blueberries are rather demanding plants. They need constant water, but they don’t like to have their roots sitting in water. A regular supply of water will be necessary for the blueberries to produce well. If water is lacking or inconsistent, the blueberries will be small, puckered, or non-existent.
Sunlight: Pick a spot on your property that gets the most amount of sun. Since plants harvest sunlight and turn it into carbohydrates, which are the delicious, flavorful sugars that will plump up your blueberries, picking a spot where the blueberries will get maximum sun exposure will ensure that your plants will produce an abundance of full-sized blueberries.
Soil/Nutrients: There are three soil requirements to successfully growing blueberries: acidic, rich in nutrients, and well-draining but able to retain moisture.
Variety: There are basically 3 types of varieties of blueberries: highbush, lowbush, and rabbit-eye (there are several cultivars of each variety). Highbush and lowbush varieties are best suited to areas that get colder during the winter. They need a certain number of ‘cold hours’ each winter, or they won’t produce (or produce poorly) the following year. Rabbit-eye blueberries have been bred to tolerate fewer cold hours and still produce.
Remember that you’ll need more than one type of whatever variety you choose (there are several cultivars each of highbush, lowbush, and rabbit-eye) in order to have the cross-pollination needed to produce berries.
Blueberries are one of only a handful of plants that will only thrive in such acidic soil. The majority of plants do well at a soil pH between 6.0 and 7.0 (slightly acidic to neutral). Blueberries will grow best in a soil with a pH of 4.5 to 5.5… and in case you didn’t know, that’s REALLY acidic! Rainy regions tend to have acidic soil, and arid regions (dry or desert areas) tend to have alkaline soil. But that’s not always true. Your soil pH may be higher or lower than typical depending on if you live near a pine forest or the white cliffs of Dover, so it’s still worth testing your soil. You can either buy a soil test kit (you can find them at most of your local garden centers), or you can send a sample to your local extension service.
AMENDING SOIL TO ACHIEVE CORRECT pH
For gardeners with alkaline soil (or soil with a pH higher than 5.5, which is basically the upper limit for successfully growing blueberries), it’ll be a bit of a challenge to grow blueberries, but don’t give up quite yet. It’s still possible; it might just take a little more planning and preparation.
To amend your soil to make it more acidic, there are basically 2 things you can add: sulfur, and organic matter. Organic matter contains lots of nutrients and minerals, most of which are acidic. As the organic matter breaks down and releases the nutrients, minerals, and other bits and particles, your soil will become slightly more acidic. Composted pine needles are probably the most acidic organic matter you can add to your soil, since the pine needles themselves are already acidic, but they break down really slowly, so be prepared for some time investment (since you’re not likely to find a good compost you can purchase made from composted pine needles).
The other thing you can do is add sulfur. Sulfur is very good at lowering the pH of your soil (making it more acidic), but it’s not too good at sticking around, so you’ll have to apply sulfur at regular intervals to keep the soil pH from climbing. Every 3, 6, or 12 months, take a sample of the soil your blueberries are (will be) growing in and test the pH. If the pH has risen, add more sulfur to the soil. It can take a year or two to effectively bring the pH down to a level that’s suitable for the blueberries, but it’s worth the investment in the long run.
GROWING IN POTS
If your soil is very alkaline (I’ve seen some with a pH over 10.0!) and it’s not really possible to bring it down to the necessary pH, or you don’t want to wait 2 years, it might just be easier to grow your blueberries in pots. There are smaller cultivars that will grow and produce well in pots, though not quite as heavily as bushes planted in the ground.
Make a mixture of 3 parts organic matter and 1 part sand (true sand, if possible, not crushed up quartz), mix well, and fill your pots. Don’t bother putting rocks or broken bits of clay pots at the bottom of the pot; just fill it up with the compost/sand mixture, to about 2 inches below the edge of the pot, with the compost & sand mix. Make sure you choose compost/organic matter that has been well-composted. The particles should be small, and there should be hardly any big bits in it, if at all. Also, make sure you choose nice, big pots, as big as you can get, at least with a 2 1/2 to 3 foot diameter.
As long as you have chosen blueberry bushes that can tolerate the level of freeze/heat in your area, you can sink the pots ¾ of the way into the ground and leave them there year-round.
WATER & NUTRIENTS
Now, on to the other two soil requirements: rich in nutrients, and well-draining but able to retain moisture. Organic matter not only acidifies the soil, it can also help solve these problems too.
Organic matter/compost is often rich in nutrients, especially when it’s well-composted (that’s not always the case, but it’s likely). If it’s not well-composted, it can actually have the opposite effect, pulling nutrients away from plants, particularly nitrogen.
Organic matter is also able to hold onto water. Organic matter particles can absorb up to 6 times its weight in water! This means that the soil will contain tons of water, but it won’t be filling up all the space the plants’ roots, leaving plenty of room for air. Plants’ roots need to be able to ‘breathe’, and if the soil doesn’t drain well enough, it can kill your plants.
With organic matter worked into the soil, however, the variously sized particles keep the soil porous, which allows plenty of room for oxygen, plenty of space for the water to drain so there’s no standing water, and the organic matter particles will swell up with water, like a sponge, ready to release water as the plant needs it. Compost really is magical stuff. No wonder gardeners call it black gold.
A quick note on water – some water, particularly in desert areas, is very mineral rich, which makes it very alkaline. If you water with alkaline water, it will have an effect on your soil pH over time, and then you’ll have to fight the battle back to a lower pH by adding organic matter and sulfur.
The best way to avoid escalating the ‘alkaline problem’ by using hard water is to collect rainwater in rain barrels, and use the water from the barrels to water your blueberries. Rainwater is almost always lacking in hard minerals, which makes it less alkaline (more acidic), and a more suitable option for your blueberries.
As long as you’ve worked plenty of organic matter into the soil, the best way to water is less frequently and deeply. Meaning that you should water less often, but make sure you water thoroughly each time. The water will slowly percolate downward, and the roots of your blueberry bushes will try to follow the water deeper and deeper into the soil, which will help your blueberry bushes to establish a deep, strong, healthy rootstock, with a greater area for pulling nutrients and water from. If you water every day, the blueberry bush has no need to push deeply into the soil to find the water it needs – it’s getting more than enough on the surface. Either way, be consistent with your watering schedule, and never let your blueberry plants dry out.
During dry spells, especially if humidity drops, be sure to water more frequently. When the air is dry, it exerts a greater pull on the moisture from the leaves of the blueberry bushes, robbing your plants of some of their water, which they then have to replenish by pulling in new water through their roots.
The best time to transplant or pot up blueberry bushes is in the spring because the air is cool, and moisture is not lost so quickly. It also gives your plants plenty of time to become established before winter hits. Always water new plants as often as necessary and never let them dry out. As your plants become more established, you can begin to water less frequently.