SIX TIPS: Here are six foolproof tips for growing healthy productive blueberries in your backyard and garden.
ONE: Yummy Acidic Soil
Blueberries are in the family Ericaceae along with azaleas and rhododendrons and prefer slightly acidic soil with a pH between 4.5 and 5.5. However, if your soil isn’t already on the acidic side it takes some work and time to get it there so instead, I grow mine in half barrels where I can mix the soil to perfection from the get-go by starting with more acidic soil. Most soil companies carry an acid lover's soil mix or a soil acidifier mix. Adjusting the soil is one of the single most important things you can do if you are having any problems with your blueberries. If your pH is low (below 4) you can add lime to increase it. If it’s too high (above 5.5) you can add elemental sulfur or aluminum sulfate to lower it, ideally well before planting. If you already have established plants, you’ll need to incorporate these amendments deeply into the soil near the rooting zone.
TWO: Sunny Location
Blueberries like a sunny location and moist, well-drained soil, which is also easy to do with a half barrel. Most blueberries also need a cold spell but, thankfully, there are now several varieties that can be grown in warmer climates like mine in the Bay Area in California that require very little chilling.
THREE: Moist, Well-Drained Soil
Blueberries have a shallow, fibrous root system and are susceptible to drought injury or root rot if they are overwatered. To be happy, they require 1-2 inches of water every week between May and September, ideally an inch of water twice weekly at the outer leaf line to reach all of the roots. Maintain a constant mulch to a depth of 3-4 inches adding an inch each year.
FOUR: Planting
Look at your local nursery for bare-root plants that are 2-3 years old and gently spread their roots out in all directions when you plant them. Remove any flowers or fruit that develop in their first year to send more of the plant's resources directly to the plant and root growth.
FIVE: Feed Me
This is something I got wrong in my first two years of growing blueberries. Blueberries like to be fed 1/2 cup of fertilizer 3-4 times a year starting in the spring and every other month up to the fall. Good organic options are feather, blood or fish meal, or 10-10-10 fertilizer with a potassium sulfate (not chloride) or ammonia sulfate 3-4. Spread the fertilizer out at the leaf line or if you are growing them in barrels in the outer four to five inches of the barrel away from the center stem so that it makes it down to the outer roots encouraging root growth. I just fed both of my blueberries in half barrels last weekend.
SIX: Prune Me Annually
Once established, remove any dead or dying parts, and any spindly growth at the base of the plant. Aim your pruning at getting lots of airflow and sunshine to all of the branches and leaves, clipping any overlapping branches and those crowding at the center! The fruit is produced on the 1-year-old wood.
Sources:
California Master Gardener Handbook (2nd Edition)
Golden Gate Gardening by Pam Pierce