How to Grow Blueberries

Kids enjoy delicous blueberries.  Easy to pick and eat!

Shown below  are instructions for how to grow blueberries including preferred conditions, step by step planting instructions and yearly care.  Blueberries are, like grapes, a reliable source of homegrown fruit for our region (central Pennsylvania - zone 5).  We usually have mild frosts in the spring while they are blooming but the blooms are tough and set fruit anyway.

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Characteristics & Preferred Conditions

Step by Step Planting Instructions

Care after planting

Chandler blueberry

Chandler (above) gets huge quarter sized berries in rainy years.

Characteristics & Preferred Conditions

Life Cycle:  Blueberry bushes are deciduous shrubs.  In spring, the flowers come out just a bit ahead of the leaves.  In late spring new shoots start to grow from branches and from the base of the bush.  Berries ripen from June through August depending upon your latitude and the variety.  In fall the leaves turn lovely shades of red and then fall off.

Soil:  Sandy loam or silt loam.  Well draining. 

pH:  5.0 (highbush)

Light:  Full or part sun. 

Spacing:  4 feet apart or more.

Blueberry bushes in the fall

Mulch:  Blueberries like the soil to stay moist.  If your area gets long hot dry summers, then mulch is a must.  Blueberries that are grown in blueberry habitat such as the high rolling wooded hills of Pennsylvania can manage without it but they still perform better if mulched.  Since blueberries prefer acid soil its OK to use oak leaves and brown pine needles as well as the usual bark mulch. 

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Blueberries blooming

Water:  Blueberry plants love water, lots and lots of water.  But they don't like standing water so the soil needs to drain well.  Our best year by far was 2013.  It rained so much here in the spring that the drainage ditches overflowed, and the lane washed out.  The blueberries were the biggest and sweetest we've ever had.  Even in our cool highland location, we get bigger and better berries in a rainier than normal years.  Deep watering is not necessary since the roots are close to the surface.  Blueberries prefer a small amount of water all the time. 

Irrigation:  Soaker hoses and drip systems, can provide this slow steady supply of water without the hassle of lugging hoses around.  They need to be designed to;

  1. distribute the water evenly all around the plant,
  2. not water the crown or trunk of the bush, and
  3. not wet the leaves.

Planting Blueberries

Blueberry bushes can be purchased and planted as bare root/dormant, potted/dormant or potted/leafed out plants.  If your blueberry plant has leafed out, don't plant it outside until all danger of frost is past. 

Materials

  1. pH Test kit
  2. Shovel
  3. Water (hose or large bucket full)
  4. Dirt container:  plastic sheet 3 ft x 3 ft  or bigger, wheel barrow, large tote (optional)
  5. Peat Moss
  6. Sulfur (acidifier):  Elemental sulfur and/or Calcium Sulfate (Gypsum). 

Adjusting pH

You can adjust the pH before or after you plant.  In either case the sulfur is sprinkled on the surface of the ground and watered in.  Sulfur containing acidifiers have different strengths so the amount to add depends on which product you use.  Most products will state the amount to use per 100 sq ft. to get a 1 point reduction in pH. 

Example:

  • If the bags says to use 10 lbs per 100 sq ft
  • and the 3 ft area around one bush is πR squared = 7 sq ft.
  • and 1 lb = 2 cups of acidifier (find on the bag)

  10/100 x 7 = 0.7lbs = 1.4 cups

If your pH is 7.0 you'll need to use 2.8 cups per bush. 

We do not recommend reducing the pH by 2 points in one application.  It will take some time for the sulfur to diffuse into the soil.  The pH at the surface (where many of the roots are located) may be reduced too much since the sulfur is concentrated there.  A more prudent approach is to apply enough to lower the pH by 1 point.  Water it in over 2 weeks.  Then do a second application.

Sulfur treatment zone around a blueberry bush

For new blueberry plantings the sulfur treatment zone should extend beyond the root ball to enable nutrient uptake for new roots and encourage root growth (~3ft circle).  For mature bushes the zone should include the ground within the drip line plus at least a foot beyond that.

Health Note: Do not use aluminum sulfide containing acidifiers around plants intended for food.  Aluminum has negative health consequences which is why it isn't recommended for cookware.

Notes:

Some products offer acidifier and fertilizer in one which is fine to use once the bush is leafed out or established.  Don't use these when first planting.  Its too easy to burn the plant. 

Don't purchase organic products that are not sterilized.  We used a name brand organic product on our blueberries.  Some of the dust got on the leaves and within a week the bushes were dying of a fungal disease.  We lost 5 plants.

Planting Procedure

  1. Test the pH of your soil. If it is higher than 5.0 you will need to add sulfur.  See the Adjusting pH section below left.
  2. Water the blueberry bush if the soil in the pot is dry.
  3. Place the dirt container beside where you want the bush to go (Optional).  This protects your grass and provides a place to mix the soil with amendments without loosing any material.
  4. Dig a hole slightly deeper than the pot and about twice as wide.  If bare root, dig the hole as deep as the longest root.  Put the dirt in the dirt container.
  5. Mix a large shovel full of peat moss with the soil that was removed from the hole.  Don't add fertilizer.  Its too easy to hurt blueberries with fertilizer at this stage.
  6. Un-pot the plant.If in a peat pot, tear off the pot.  We've dug up plants after 3 years in the ground that still hadn't grown through their peat pots! 

    Keep the root ball damp while planting
  7. Hold the blueberry over the hole with the top of the roots just below the top of the hole. 
  8. Replace the amended soil into the hole, with your other hand.  Try to avoid air pockets and make sure the soil is firmed against the roots.
  9. Water thoroughly
  10. If the pH was too high, sprinkle sulfur around the bush.  Refer to the Adjusting pH secton at left for where and how much to apply.
  11. Water the bush and the sulfured zone lightly to move some of the sulfur into the soil.
  12. Add 2 - 4 inches of mulch.  Reduce the thickness right next to the base of the bush.  If you have chickens, use stones or cover mulch with wire mesh such as coated chicken wire or hardware cloth.  Pin the mesh to the soil.
  13. Continue watering the blueberries several times a week for 4 weeks (unless its raining frequently).  Water at least once a week for the rest of the summer and until dormant in the fall.  Adjust according to the weather.  ie. If its raining every other day, stop watering.  Areas suffering from drought or weeks with temps in the 90's should go back to the 3 times per week schedule.

    Avoid wetting the blueberry leaves to prevent disease.
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Blueberry Care After Planting

We've found the biggest challenges facing blueberry growers is the care after planting.  Below we discuss how to grow blueberries when your soil pH isn't quite right or your location is a bit dry or your soil isn't the peaty loam of a highland forest.

Herbert blueberry

Diagnosis:  The plant above is a nice deep green.  Young leaves (see lower left corner of picture on the right) are naturally lighter in color.  These will darken.  If the whole plant is this light green than a pH adjustment is probably needed.

Blueberries cannot obtain nitrogen from neutral or alkaline (basic, sweet) soil.   So if your plants have plenty of fertilizer but are a pale green, the most likely cause is high pH.

Weed Control

Blueberries keep their roots very close to the surface.  Weeds must be kept under control but pulling some weed species does too much damage.  The blueberries will grow very slowly, not grow at all or worse yet, die.  For the same reason, you should not use a hoe, trowel or other cutivating tool around the bushes.

Mowing and Shearing:  We mow around the plants and then use manual grass shears to trim under the branches.  Be very careful not to trim off new blueberry shoots! 

Weeds not to pull:  Crab grass, timothy, goldenrod, plantain and other rhizomatous or large complex rooted weeds.

Weeds you can pull by hand:  Dandelion and wild carrot may not come out at all but if they do the straight tap roots do minimal damage.  Usually, red clover roots don't come out so you can pull them.  Weeds such as Glechoma, pictured below, run along the surface and separate from their roots easily so pulling them doesn't do any damage.

Glechoma hederacea

Fig.  The herb Glechoma hederacea is a common weed found under the bushes in our area.

Herbicides:  Some growers use sprays such as Roundup to control weeds.  If you want to try this, be very careful to keep the spray off the blueberries since Roundup will kill them too.  Its very easy for overspray to get your desirable plants.  We also don't like the residue left in the soil around plants that are producing food for our family.

Painting Weeds Dead:  Sometimes a plant or weed grows next to your bush that is damaging the bush but you can't pull it without doing a lot of damage to the blueberry, You can do the following:

  1. Trim the weed to just above the soil surface.
  2. Verify that there are NO cut blueberry stems or roots or young shoots amongst the cut shoots of the weed. IE. its ONLY weed stems.
  3. Then using a paint brush, carefully apply Roundup to the cut ends of the weed.  You can fill hollow stems with the Roundup solution.  Keep it off the soil.
  4. You can see the weed absorb the Roundup.  Reapply if its large or known to be resistant (IE. plantain).
    Do not flick the brush or you could spray your bush.  Take your time.

Maintaining Proper pH

Often people will have to plant blueberries were the natural soil pH is too high .

What to do:  Apply acidifiers such as elemental sulfur or Calcium Sulfate (Gypsum). 

Don't use acidifiers that contain aluminum

Frequency:  Yearly or whenever the plants start to yellow.

How much:  This varies with the product you use.  For details click the link below:

Adjusting pH

Friendship Blueberry

Pruning Blueberries

Healthy growing blueberries are less challenging to prune than grapes or apple trees.  Remove dead or discolored branches, and discolored or misshapen leaves during spring, summer and fall.  Be very judicious about this.  This is crucial to growing organic blueberries. 

The amount of and type of pruning needed to encourage proper shape, size and good air circulation varies with the variety.

Top Dressing Blueberries to Improve Poor Soil

Heavy Clay soils:  Mix 1/3 sand and/or potting soil mixed with 2/3 materials high in humus such as rotted leaf litter, manure or peat moss.  Remove mulch and apply mixture about 1 - 1.5 inches thick.  Replace mulch.

Sandy soils:  Remove mulch and apply about 1 - 1.5 inches of humus (rotted leaf litter, rotted manure, peat moss or a mixture) to help with water retention.  Replace the mulch.

Do Not mix the amendment into the soil surface since this will destroy the blueberry roots.  Just apply to the surface (top dress).  The bushes roots will move into this well draining nutrient rich surface material.  Top dressing also helps improve the quality of the deeper soil over time by attracting worms.

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