Ultimate Guide To Growing Blueberries – How To Grow Delicious Blueberries, According To Science

Blueberries (Vaccinium corymbosum) are widely considered to be a superfood and can be expensive to buy in packets from the supermarket. A superfood is a plant-based food (although, it can include fish and dairy products) that are considered highly nutritionally dense. [1]

Blueberries are native to North America and could, originally, only be found growing in the wild. Then scientists got involved and discovered how to cultivate the plant for agricultural and domestic use.

The blueberry bush has certainly picked up the beauty of its distant cousins - the rhododendron and the azalea.  Blueberry plants have beautiful foliage in the fall and lovely, cream-coloured flowers in the spring, so not only will the bush produce delicious fruit, but they make great ornamental plants.

There are three categories of blueberry plant - highbush, lowbush and hybrid half-high. Science has tended to focus on the highbush varieties, so these are the most common varieties. [2]Blueberries contain anthocyanins which give the berry its distinctive, instantly recognisable colour. Anthocyanins are thought to have numerous health benefits: maintenance of healthy bones, lowering of blood pressure, preventing heart disease and cancers. [3]


Blueberries can help protect our cells against free radical damage. They’re rammed with powerful antioxidants (as well as Vitamins A and C) which are believed to help inhibit the growth of tumors, whilst limiting inflammation in the body and warding off cancer.

These super-berries can aid digestion and help to improve our mental health. The Vitamin C found in blueberries can help the skin produce collagen, keeping us wrinkle free! [4]


A blueberry bush can produce fruit for up to 20 years, with proper care. That’s a heck of a lot of berries! [5]

So, wouldn’t it be great if you could grow your own supply of these power-packed, super-food berries in your own back yard? Read on for the ultimate guide to growing delicious blueberries.


BOTTOM LINE - Blueberries are GOOD for you! Classed as a super-food, they’re packed full of antioxidants, anthocyanins and Vitamins A and C. Consumption of blueberries is reputed to help  ward off illnesses, including cancer.

Grow in pairs

Blueberries bushes don’t like to be lonely. They will produce fruit on their lonesome, but they’ll do far better when they’re planted close to another blueberry bush of a different variety.

This will allow for cross-pollination which is required for a bumper harvest. Cross pollination is the transferral of the pollen grains from one flower to another of a different plant of the same species. Some combinations can be particularly fruitful. Read on for more info.


There are some self-fertile varieties of blueberry bushes that don’t require cross-pollination. However, cross-pollinated plants tend to be stronger - they benefit from greater diversity of species and greater resistance to disease. [6]

Grow insect friendly plants nearby. Foxgloves, honeysuckle, sweet william and jasmine are all great plants to have close to fruit bushes. They attract the bees, who will, therefore, be more attracted to your blueberry bushes. [7]


Even if your plant is a self-fertile variety, it will still benefit from cross-pollination with another blueberry bush. [8]

BOTTOM LINE - Grow your blueberry bushes in pairs to encourage cross-pollination which will strengthen the plant’s immunity to disease and help encourage abundant cropping.


Where & when to grow?


Plant your bush in the Fall or winter, leaving 5ft (1.5m) between each plant. Cover with a layer of acidic peat, wood chipping or pine needles.

Blueberry bushes can reach 12ft in height and a diameter of 3-5ft. Half-high varieties generally reach around 4ft, with a diameter of 3ft, so they certainly need plenty of room to grow.


Blueberries have very specific needs in terms of soil type and position (more on this later). If you find that azaleas, rhododendrons and camellias grow well in your garden, your soil will be a positive haven for blueberry bushes. These are acid-loving plants, so your soil should be between pH4.5 - pH5.5. [9]

Place your bush in full sun, in a position sheltered from the wind. They do best when when they get 6 hours of sunlight a day, but will tolerate shade during the later part of the day. At least 3/4 of the day in full sun is required. [10]


Your blueberry bush requires a well-drained soil that retains moisture. Lots of well-rotted organic matter will help with drainage and add nutrients to the soil which will help your plant thrive.

If you have a clay soil, your bush won’t be happy. The soil will be too dense and moisture retentive and could lead to root rot.


You can mix your clay soil with lime-free soil improvers - composted bark, leafmould, pine needles and composted sawdust. This will help the decrease the alkalinity and density of the soil. [11]

But, ultimately, if your soil is heavy clay it’s likely to be alkaline which is your blueberry’s worst nightmare. You’d be better growing your blueberries in a pot, so you’re in greater control over the soil acidity. [12]

BOTTOM LINE - Plant your bush in the fall or winter, in full sun with an acidic soil type. If rhododendrons, azaleas and camellias happily grow in your garden soil, your blueberries are going to party hard! Otherwise, plant them in a pot.


Grow from cuttings

Blueberry plants grow successfully from cuttings, so get raiding your neighbour’s back yards! The best time to take cuttings is during the Summer, when growth is at its most rigorous.

The night before you take your cuttings, water the plant down to a depth of 4 inches. [13]


But how do you know the water has reached 4 inches?

Stick a bamboo skewer or a screwdriver into the earth. Dry earth will be resistant - if the probe hasn’t reached 4 inches, water the soil some more. [14]


A bamboo skewer is good for this test because moist soil will stick to the sides and the skewer will feel feel moist to the touch. Bamboo skewers are better if you’re growing your blueberries in a pot as the soil is less likely to be compacted.

To start the cutting process, collect some 4-inch plastic pots - you’re going to start your plants off in these. Fill them with a half and half mix of coarse sand and milled peat moss (that has been soaked and is plump).


Firm the mixture down. Make a 3 inch deep hole in the centre of the pot - this is where your cutting is going to find its new home. [15]

Take a 6-inch cutting from the tip of a stem that is growing vigorously. Avoid stems that are in flower or already producing fruit - you’ll disrupt the cutting’s energy from developing healthy roots if the plant is already trying to reproduce.

Cut the cutting at an angle, and sharpen like a pencil to create a pointed end. Remove any leaves along the lower half of the stem.

You’ll need some rooting talc (indolebutyric acid). Pour it onto a sheet of newspaper and cover the sharpened end of the cutting with the powder.

Place the bottom 3 inches of the cutting into the prepared hole in the compost. Firm the soil around it. Make sure that it’s standing up straight. Water the cutting lightly.

The pot will need to reach 70ºF, so place it on a propagation mat if the ambient temperature outside is below 65ºF. If you can, place the pot in a cold frame that is lightly shaded.


Only water when the surface soil has dried out. Keep the soil moist but not sopping wet.

Leave the cutting in the pot for 2 to 3 months until roots have set. At this point, give the cutting a light tug - it should be resistant to lifting, indicating that roots have taken to the soil.


If roots are developing well, you can transplant the plant to a 6-inch pot filled with the same acidic potting mix that the adult plant requires (see “What type of soil do I need to grow blueberries?”).

Water only when the top soil is dry down to an inch. Keep the plant under light shade during the Summer. [16]


When the plant has taken well and is showing signs of healthy growth, you can start to “harden off” the plant over the course of a week. In other words - you are preparing a plant grown under cover for its new life outside.

To harden off, bring the plant outside during the day to get it used to direct sunlight, wind and the rain and put it back inside overnight. After a week, your plant should be used to being outside and can be left outside permanently. Keep an eye on the plant over the next week or so, to make sure it’s adapted to its new habitat. It should thrive in the open air. [17]


Now you’re ready to transplant your new plant into a permanent position in time for the first rains of the Fall.

BOTTOM LINE - Blueberries grow very successfully from cuttings. Water the plant well beforehand and take a cutting from a stem with vigorous growth, but not one that is already in flower or fruiting. With some preparation, you’ll have a strong plant that will grow into a producing adult.


What type of soil do I need to grow blueberries?

The blueberry is an acid-loving plant, so you need a soil with a pH of 4.5-5.5. You might recall from high-school that substances are either acid, neutral or alkaline on a scale of 1 (being most strongly acid) to 14 (being most strongly alkaline). Water is neutral at pH 7.

Use a soil acidity tester each spring (read on for advice!). If the pH is too high, add some sulphur chips to address the alkalinity.


General potting composts won’t have the right level of acidity to satisfy the blueberry. Use an ericaceous compost which has been formulated to cater to lime-hating plants. Ericaceous composts are widely available in garden centres.

Ericaceous compost is often packaged as suitable for azaleas and rhododendrons. The packaging might not mention blueberries at all. But don’t worry - this is what you need. [18]


The soil must be well-draining. If your garden soil is a heavy clay, you can increase the drainage by adding rich organic matter into the soil, such as manure (which will also increase the soil acidity). Alternatively, this can be added as a top soil.

“Hilling” the plants can improve drainage. This means that you plant them in a little mound, 12-18 inches above the normal soil level. Don’t plant over the existing crown of the plant, as this can lead to trunk rot.


Growing blueberries in pots is a particularly effective way of controlling the acidity and density of the soil.

BOTTOM LINE - Blueberries love an acidic soil of around pH 4.5 - 5.5. You’ll need an Ericaceous compost which is often sold as soil for rhododendrons and camelias. You can decrease the alkalinity of your compost by adding well-rotted organic matter.

If your soil is too alkaline, you should consider growing your blueberry plant in a pot.

How to test the pH of your soil

There are a number of ways to test the pH level of your soil. You can buy a kit or there are several classic DIY methods that can be just as effective, and still scientifically sound.

Bear in mind that the pH of your soil may differ from one end of your garden to the other, so be sure to test several sections.


First for some DIY methods -

The baking soda and vinegar solution

1. Collect several cups of soil from different parts of your garden. Put 2 spoonfuls into separate dishes.
2. Add 1/2 cup of vinegar to the collected soil. If it fizzes, you have alkaline soil - the pH will be between 7 & 8. Boo - no good for blueberries.
3. If the soil didn’t fizz, you can test for acidity. Add some water to a couple of spoonfuls of soil and mix into a mud-cake consistency. Add 1/2 cup of baking soda. If this fizzes, you have an acidic soil, around pH5 and 6. Hurray - get those blueberries planted.

If your soil reacts to neither of these tests, your soil has a neutral pH (7).  


NB - Tap water might affect the results of these tests because it can be lime-heavy, especially if you live in a hard-water zone. Use bottled or distilled water for a more accurate result. [19]

The Cabbage Water pH test

This works like everyone’s favourite high-school Litmus test experiment, where the colour changes according to the acid or alkaline content.

1. Boil up 2 cups of distilled water.
2. Add 1 cup of chopped red cabbage and simmer for 5 minutes.
3. Remove it from the heat and let it sit for 30 minutes.
4. Strain the cabbage from the liquid which should, by now, by a purple/blue colour with a neutral pH of 7.

The test
Add 2 teaspoons of collected soil into a clear jar. Add around 2 inches of cabbage water. Stir well and wait. After around 30 minutes, the colour will have changed.

If the water has turned pink, you have acidic soil which will be great for your blueberries.


If the water has turned blue/green, you have alkaline soil and you’ll need to treat the soil (or grow your blueberries in a pot). [20]

Or you can buy a kit

Alternatively, you can buy a soil-testing kit or a probe. But that’s not as much fun, is it?

BOTTOM LINE - There are several ways of establishing the pH level of your soil. A simple mix with vinegar or baking soda will tell you as much as a professional kit. If your soil is too alkaline, you’ll need to grow your blueberry plants in a pot.


How do I adjust the pH level of my soil?

Adjusting the pH level of your soil takes time - you can’t do it all in one go. You’ll need to make  several applications of soil improver over a couple of months to affect a long-lasting change, so you need to plan in advance if you’re planning on planting in a alkaline soil.

You can lower the pH of your soil by adding sawdust from any conifer (pine, spruce, fir) to the growing site. If your soil is too alkaline, you can also add granular sulphur - 1 lb per 50 ft will do the trick. Alternatively, 2 tablespoons of vinegar added to each gallon of water will help acidify the soil.


If the leaves of your blueberry plant begin to turn yellow, it has a Nitrogen deficiency. [21]

Used coffee grounds add nitrogen to the soil and increase the acidity which are both required for successful blueberry bushes. You can also add well-rotted manure to increase nitrogen levels of the earth. [22]


If the soil in your garden is higher than pH8, sulphur chips won’t be enough to bring down the alkalinity. The best solution, in this case, is to grow your blueberry plant in a pot. [23]

BOTTOM LINE - You can add well-rotted manure, sulphur chips, saw-dust, pine needles or even diluted vinegar to your soil to increase the acidity. Coffee grounds add nitrogen and acidity.


However, if your soil is pH 8 or above, you should consider growing your blueberry plant in a pot.

To pot or not to pot?

Many people choose to pot their bush due to the additional control you have over the soil. Potting also helps you to keep the plant productive and manageable in size. Pots usually dry out more quickly though, so keep on top of the watering. Potting is the best option if your garden soil is too alkaline.

Potted bushes are more likely to bear fruit because the soil and water conditions can be better regulated. However, potted bushes may take longer to start producing fruit. So, swings and roundabouts, as they say. [24]


The pot must be big enough to let the roots spread out and filled with a good ericaceous compost. A pot of at least 18” is recommended to encourage vigorous growth.

Blueberries need plenty of sun to keep the plant productive - 6—8 hours in full sun is recommended. A flower-bed that was once sunny, can become shaded over time if close to a tree. With potted bushes, you have the added benefit of moving your plant to the sunniest part of the garden. [25]


Full sun does not necessarily mean an area in sun throughout the full entirety of the daylight hours. An area that gets at least 6 full hours of direct sunlight is considered to be “full sun”. [26]

Potted bushes should be planted in early Spring. Ensure that you purchase your bush from a garden-centre with a great reputation. One to three year old bushes are the best choice. [27]


Your pot needs good drainage with at at least one drainage hole. Broken terracotta or gravel placed at the bottom of the pot provides extra drainage which prevents the roots from rotting. However, if you add too much gravel the soil will dry out too quickly.

The best way to ensure sufficient drainage to “double pot”. Place broken terracotta or gravel in a empty decorative pod and put the blueberry plant’s pot on top of that gravel or terracotta. This will ensure that the soil gets drainage and space to soak up the water, preventing premature dry-out. [28]


Keep the level of acidity in the soil and stop it from drying it out by mulching. Mulching is basically adding a protective layer of organic matter on the top of the soil which enriches the soil and adds insulation to the plant’s roots. Add pine needles, pine bark or true cypress to the top of the soil of your blueberry pot.

BOTTOM LINE - Pots are good. You can control the soil conditions much better than in your flower-bed but make sure that the pot is big enough for your plant to develop big, healthy roots.


You might have to be patient, because your plant may be slower to start producing fruit when it lives in a pot, but once it’s started, there won’t be any stopping it.

Potting a plant means that you can pick the sunniest spot in your garden to help your plant capture as much sun-light as possible.


Hot to repot your shop-bought blueberry bush


When you buy your plant, the pot is likely to be too small. This is to keep the bush small whilst in the garden centre where shelf space is at a premium.

When repotting, remove the “memory” of the pot. The soil and the roots of the plant will have moulded to the shape of the original pot. Without some help, this “memory” will slow down the development of the roots in the new pot. Gently prizing the roots from the sides of the soil-base. This will stimulate the roots to spread out into the new, larger pot.


The top of the existing soil of the pot in which you bought your plant is called the “crown”. It’s really important to not plant over the crown, as the trunk may rot. [29]

Pro tip! When you’re filling the new pot with compost, place the existing potted plant in the soil and fill around the pot. Firm the compost around the pot and when you remove it, there will be a hole in the compost exactly the right size for your plant! [30]


BOTTOM LINE - Removing the “memory” of the pot will help encourage the roots to grow into the soil in its new home.

Should I stake my blueberries?

Blueberry bushes are upright and erect so don’t usually require staking for support. You could use a trellis to train the bush, however. This adds to the plant’s ornamental qualities.

Training and trellising your plant may allow for better access to the fruit, as the bush can expand across a wall or a fence.


Trellising can improve air circulation for the fruit, preventing rot in wet weather conditions. Sunlight will hit the full, open plant, rather than focusing on the outer branches, so could be beneficial for flowering and pollination, and could, therefore, result in better fruit production. [31]

In combination with proper pruning (more about that later), trellising and training your bush could certainly benefit its fruit production.


BOTTOM LINE - Staking is not usually required. Trellising and training the plant could result in better fruiting.

How tall will my blueberry bush get?

Blueberry bushes are ornamental with attractive pink-tinged flowers and, with proper pruning, won’t take over your garden or patio.

The potential height of your plant will differ depending upon the bush variety and the region it’s growing in. [32]

Variety

Height

Width

Good combinations for cross pollination

Highbush Blueberry (Vaccinium Corymbosum)

6-12ft

8-12ft

Bluecrop (Vaccinium coyymbosum “Bluecrop”) / Blueray (Vaccinium coyymbosum “Blueray”)

Rabbiteye Blueberry (Vaccinium Ashei)

8-10ft


Beckblue (Vaccinium ashei “Beckyblue” / Bonita (Vaccinium ashei “Bonita”) / Woodard (Vaccinium ashei “Woodard”)

Half-High Chippewa (Vaccinium Chippewa)

3-4ft

3-4ft

Polaris (Vaccinium “Polaris” / Northsky (Vaccinium “Northsky”)

Southern Highbush (Vaccinium Corymbosum X Vaccinium Darrowiiwere)

3-6ft

3-6ft

Sharpblue / Sunshine Blue

JellyBean (Vaccinium corymbosum BrazelBerries “Jelly Bean”) (dwarf variety)

12-24 inches

12-24 inches

Peach Sorbet

Peach Sorbet (Vaccinium Corymbosum BrazelBerries “Peach Sorbet”) (dwarf variety)

24 inches

24 inches

JellyBean


BOTTOM LINE - The potential height of your plant depends on the variety you’ve chosen. Remember that cross-pollination works best for all blueberries, even if they’re self-fertile, so you might not need the same amount of space for both plants, if you’re planting in pairs.


Don’t let your bush produce fruit

Well, that sounds counter-intuitive, doesn’t it?

Obviously, you want your plant to produce a delicious, edible crop. But there are a couple of guidelines to follow to ensure that your plant grows strong enough in its early years to produce abundant harvests in the future.


If you let your bush produce fruit in its first year, it will remain tiny and weak, focusing its energy on producing fruit rather than developing strong roots and body growth. Like asparagus and globe artichokes, it’s generally recommended that you wait until year 3 to let it produce.

In the first 2 years - painful as it may be - pinch back the blossoms. It will be worth it in the long run! You’ll still have plenty of attractive foliage to look at.


During this growth period, you won’t need to prune the bush. Start pruning at the end of year 3. [33]

BOTTOM LINE - Give you plant plenty of time to establish and it will repay you with up to 20 years of delicious treats! Let it develop strong roots for the first couple of years.


A little patience will pay off. And in the meantime, you bush will be ornamental and an interesting addition to your bed or patio pot.

Water Well

Make sure that you give each plant between 1-2 inches of water per week. Take into account natural precipitation - if it’s rained a lot you probably won’t need to water. [34]

But what the heck is 1 inch of water?


1 inch of water is equivalent to 623 gallons per 1000 sq ft, making it roughly 0.62gallon per sq ft.

An 18” diameter pot has a surface area of 1.76 sq ft, so you should apply between 1.09 and 2.18 gallons of water per week. Remember, that a pot is likely to dry out more quickly than the garden soil, so keep a watchful eye on the soil.


If your plant is growing in a flower bed, then use the calculation of 0.62 gallons per sq ft and calculate the rough surface area of the bushiest part of your plant.

This is all a bit technical - all you really have to worry about is to keep the soil moist at all times. Don’t let it dry out, but it should never be soggy and claggy. If water sits on the top of the soil, stop watering straight away. [35]


If possible, water with rain-water rather than tap water. Tap water can be too alkaline for your blueberry bush. [36]

Once your plant is established in its permanent home, you’ll need to add a good quality feed to the water. Add one ounce of 10-10-10 fertiliser per bush whilst in bloom after the first year. Increase the rate by one ounce per year thereafter, to a maximum of 8 ounces for mature bushes. [37]

Blueberries are shallow rooted, so require more watering than other fruit bushes [38]

BOTTOM LINE - You should ensure that your plant gets between 1 and 2 gallons of water per water, dependent upon its size. The compost should always be moist, not sopping wet and claggy. You shouldn’t let the compost dry out.


Pruning

Although it seems counter-intuitive to cut back a plant to stimulate growth, this is exactly the case. So yearly pruning, after year 3, is essential in order to ensure that your bush focuses energy on fruit production, rather than foliage growth.

Prune the bush in the Spring when it’s still dormant. February or March will probably be the best time, depending upon your regional climate. You want to ensure that the plant has a good collection of young, red stems with plenty of fat, fruiting buds.


Fruiting buds are fatter than “vegetative” bud which will grow new branches. Look out for the stems with the most fruiting buds - you want to keep those.

Two year old stems are most productive. Older wood needs to be cut back down to the crown to allow new stems to grow. Remove any dead or unhealthy looking stems around the plant to make sure that the plant focuses all of its energy on healthy, productive potential.

Blueberry bushes often send out low, horizontal stems which can also be removed, to keep the overall shape of the plant attractive. [39]


BOTTOM LINE - You don’t need to prune for the first 3 years after transferring your blueberry bush. After year 3, yearly pruning will help stimulate growth and fruiting.

Common problems

Birds: Birds love berries of all types, so it stands to reason that your blueberry bush with it’s jewel-like fruit is a likely target. If you find that your plant has become a target, cover the full bush with netting. Scare-crows can work, but they can also freak out the kids!

Disease: Powdery Mildew is a fungus. It looks a bit like spots of talcum power scattered over the surface of your leaves and it can stunt the growth of your plant, turning the leaves yellow.


You can treat this infection by rubbing infected leaves together to remove the powder. You should remove badly infected leaves. Don’t compost them, or the disease could spread.

Powdery mildew is a fungal disease that thrives in hot and humid weather and appears most prominently on leaves, but can also appear on plant stems and on flowers. Avoid over-head watering - try to keep the leaves dry. It’s often caused by drought stress, so ensure that you don’t let your plant dry out too regularly.


It’s advisable to spray infected plants with a fungicide to prevent further spread of the disease. [40]

Well-rotted organic matter added to the soil (such as garden compost) can help increase moisture retention. Mulching around the base of the plant can also help retain moisture within the pot.


You can avoid infectious spores lingering for the next year by removing fallen leaves in fall.

You can use fungicides to treat powdery mildew - Tebuconazole with trifloxystrobin (Bayer Fungus Fighter Plus) can be effective. [41]


Aphids: Greenfly can plague your blueberry bush. Colonies may develop on the softer shoot tips close to the branch or on the leaves. They feed on the sap from the plant and excrete a sticky honeydew substance that can easily introduce black sooty moulds, further damaging the plant.

You can spray your plant with an aphid chemical such as Garden Safe Insecticidal Soap which is an organic pest controller recommended for use on fruit bushes and trees. It’s also safe for use in the greenhouse.


Alternatively, the more hands-on approach is to use your finger and thumb to squash the attacking colonies. If you don’t like the idea of cold-blooded murder, go for the organic chemical attack. [42]

BOTTOM LINE - Birds will attack all berry bushes, so you may need to protect your bush with a net during the fruiting season. Or get a cat - that generally scares the birds off.


Aphids can colonise your plant and powdery mildew can be a problem. Both have simple solutions.

Common varieties

Tophat

Tophat (pro. Top Hat, not “toffat”) is a self-fertile variety which produces a dwarf blueberry in abundance. It’s a small plant, so won’t take up lots of bed- or patio-space. They grow to a height and spread of just 2ft. The plant introduces a beautiful autumnal colour in the fall and the berries are delicious.

Spartan’ AGM

AGM means “Award of Garden Merit” from Royal Horticultural Society (UK)

Spartan’ AGM is an early- to mid-season cropper. It produces large fruits with a sweet, tang. This plant is very hardy, but needs another blueberry cultivar close-by to produce fruit.

Nelson

Nelson is a self-fertile variety that is also very hardy. It produces large fruit in the mid- to late-seasons. Perfect for the home fruit garden due to the large produce and great flavour.

Duke’ AGM

Duke’ AGM is a great variety for the more northern climes where the growing season is shorter. It flowers late, but produces crops early. This is quite a bushy, upright variety that can grow to 6.5ft. With attractive creamy-white, cylindrical flowers that the bees love, this makes for an attractive addition to the garden, these produce beautiful purpley-blue fruit that will ripen in mid- to late-summer. [43]

BOTTOM LINE - There are hundreds of different varieties available, but remember that growing two different varieties together will ensure a better harvest, even if you are growing a self-fertile variety.

Leave a Comment

+1
Tweet
Share22
Share
Pin