How to Grow Blueberries in Alkaline Soil

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When it comes to growing blueberries, you either have it or you don’t. The “it” being perfect soil conditions. I don’t have perfect anything. That would be incredibly boring. It’s all about soil pH. Before you bale thinking I’m going to get all sciencey on you, hang in there. You need to know this if you want to grow these little blue antioxidant-packed flavor bombs.

The pH scale goes from 0 to 14, with 7 being neutral. Values below seven indicate an acidic soil and those over seven indicate an alkaline one. An acidic value between 4.5 and 5.5 is the sweet spot for growing happy blueberry bushes. Several years ago, I did a soil test and sent a sample to A&L Greatlakes lab in Fort Wayne, IN, for analysis. I wanted confirmation for something I already knew but wanted a number to establish a starting point. Hovering right around 7.5, my in-ground soil wasn’t going to support healthy, productive blueberry plants.

In the Midwest, heavy alkaline clay soil is a certainty. Like death and taxes. One approach would be to top dress and scratch in soil acidifier around each plant. But that only goes so far in alkaline soil. Alkaline soil wants to be alkaline. Adding acidifier to a determined environment is nothing short of a fool’s game, not to mention a waste of cash. Which is why raised beds and containers are the way to go for growing acid-loving blueberries. It’s so much easier to control soil pH in a confined space. Gardeners are the ultimate control freaks.

Fortunately, controlling soil pH in a contained environment is as easy as it gets. I haven’t tested the soil in my raised beds and assume it falls in the alkaline category because everything else does around here. Because I have just one plant, I simply sprinkle seven tablespoons of True Organic Soil Acidifier around the drip line. That’s the imaginary circle in the soil that’s determined by the outermost tips of your shrub. This is the target zone for feeder roots and where nutrients are absorbed. Package directions recommend 3.5 tablespoons per square foot of growing space. Since my plant occupies about two square feet, I simply multiplied the amount by two and worked it into the soil.

I follow up monthly with six tablespoons of True’s Berry Food applied to the drip line and my little blueberry bush is happy. I am too!

A Blueberry for Small Spaces

Plant breeders are amazing people! Not everyone has space for 10-foot-tall blueberry bushes. For this reason, breeders shrunk them so us small space gardeners could have our blueberry cake and eat it too. My raised bed is exactly 4’x8′ and currently home to one Bushel and Berry Jelly Bean blueberry bush. (I’m not paid to tell you that.) At just 1′-2′ tall and wide, it’s the perfect size. I was tickled with the harvest I got from just one little shrub last summer, it’s second season in the garden. As expected, the first year’s harvest was small. To encourage the plant to put it’s energy into root production that first season, I picked off most of the flowers. I left a few for my own personal enjoyment.

Jelly Bean and the other members of the Bushel and Berry collection are self-pollinating, making the heavy fruit set of my one little plant even more impressive. And because I love the fruit so much, I want more. I’ll be adding two more Jelly Beans and two Peach Sorbet. Like Jelly Bean, it’s small, producing full-size berries on a 1′-2′ plant.

And the magical part is that by growing two different varieties together, I’ll have even more blueberries for fresh eating and freezing. Cross-pollination is a wonderfully amazing thing!

Both plants develop incredible fall color too, making them a great hedging option with benefits.

Jelly Bean is hardy to zone 4 and Peach Sorbet, zone 5. My area was upgraded to 6a last year from 5b. I still consider myself a 5, mostly because I’m just so used to it and I’m skeptical of change. I had some concerns about how Jelly Bean would overwinter in my raised bed. They freeze and thaw faster and plant roots have less protection above ground.

When it comes to overwintering in containers, which I consider my raised bed to be a very large one, I follow the two-zone rule. For example, a plant left to overwinter in a container outside should be at least two zones hardier than the zone in which you live. Hardy to zone 4, Jelly Bean has survived two winters in my raised bed. I mulch heavily around it with leaves in the fall to give it a little extra warmth. Hardy to zone 5, Peach Sorbet may be a bit more tender. It will receive the same care and I’ll take the “we’ll see” approach. No promises, but my gut’s telling me it’s going to work. It’s also telling me it wants more berries.

What are chill hours?

In addition to acidic soil, there’s one more thing to consider when growing blueberries. Chill hours. Spring bloom is determined by the number of chill hours the shrub received during the winter months. To qualify as a chill hour, the temperature must be below 45 degrees Fahrenheit during the plant’s dormancy period. Requiring 1,000 chill hours, Jelly Bean is ideal for cold climate gardeners. Peach Sorbet however, needs just three hundred, making it suitable for southern gardeners.

Once a plant reaches its required number of chill hours, an internal clock is triggered that tells it to wake up in the spring instead of summer or fall. By doing so, it reaps the benefits of long warm sunny days, allowing it plenty of time to flower and complete its fruiting cycle.

Time will tell, as it always does in the garden. But I have high hopes. My eyes are on the prize which is nothing more than a few mason jars of blueberry jam, pie, pancakes, muffins, cobbler, cheesecake.

Like I said, I have high hopes.