Friday, July 5, 2013

Plant of the Week: Blueberries

Blueberries are native to North America, and have been used by Native Americans for centuries. This great tasting fruit was known by elders as the star berry due to the perfect five-pointed at the blossom end of each berry. Starting in the early 1900s, domestication of the blueberry has resulted in the many varieties of blueberries that we enjoy today!

Plant Care:

Blueberries are perennial plants that require three basic things: an acidic root zone, consistent moisture, and lots of sunshine. Luckily, growing organically and holistically can meet the first two requirements.

Blueberries are acid loving plants that require a pH between 4.8 and 5.5. Soil pH largely contributes to the availability of nutrients in the soil that plants can take up, and as a result, a pH higher than 5.5 often results in iron chlorosis. In other words, the inability to take up iron from the soil, resulting in the yellowing of leaves. On the other hand, a pH below 4.8 can result in manganese toxicity. In most cases however, the pH will be too high due to the relatively neutral pH of city compost, and the neutral pH that works best for vegetable growing. So how can we drop the pH level? There are a couple things we can do to reduce the pH. The first way includes spreading sulfur on the soil, however sulfur has properties that will detrimentally affect the soil biology if overused, ultimately degrading soil health. Other ways to lower the pH  include adding sphagnum peat, wood chips, and other organic matter, all of which are slightly acidic and will contribute to better drainage, organic matter, and build the soil ecosystem. The important thing to know is that the acidity of soil doesn’t have to be the entire soil surface. Blueberries will do just fine with a localized acidic condition to meet iron requirements.

Pruning with blueberries begins around the fifth year and happens during the dormant season (winter). Basically, excess branches and older shoots should be cut down to the base. Lastly, blueberries blossom at end of the branch, so thinning out branch tips to reduce flowers will result in better sized berries.

Pests and Diseases:
Some of the common pests for blueberries include the cranberry fruitworm, the cherry fruitworm, and white grubs. The fruitworms lay worms into unripe fruit which then hatch and feed on the fruit. Seeing blueberries webbed together with silk confirms this pest, and applications of Bt following petal fall will keep this problem in check. White grubs establish in the mulch layer and love to feed on the shallow roots of the blueberry. Some symptoms include shriveled bark and a dying bush with leaves on. One way to control this is removing the mulch layer that is directly under the blueberry bush, or a neem oil drench.


There are many varieties of blueberries and each variety has a different taste, size, and yield. The important thing to remember is that having multiple varieties that produce in the same season will result in bigger yields even if the plant is self yielding. Diversity also allows blueberries to be harvested all throughout summer.


  • Blueberries like a localized soil pH between 4.8 and 5.5
  • Mulching, sphagnum peat, and organic matter not only reduce pH, but also build healthier soil 
  • Diversity ensures blueberry harvest most of summer and bigger yields

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