Growing The Best Blueberries ... Organically
Growing your own blueberries makes so much sense! They are easy to grow and take up little space. The investment to buy and grow a few shrubs is really low, especially when compared with the price of that teeny, tiny, little, plastic clam shell of berries you find at the local grocers!
However, you need to know that planting just one shrub or even several shrubs of the same variety will not provide you with much fruit as they are not that fertile on their own.
For best production and cross pollination, you will need to have two or even three different varieties of blueberries.
We are growing about 24 plants on a sunny berm in the back potager. We chose four or five different varieties to promote better cross pollination and thus get more fruit, plus, as some are early, some mid and some late season fruiting, we extended the harvest season, as well! More fruit and for a longer period of time, win win.
1. Prepping the planting hole...
For the sweetest fruit and most production please choose a warm, sunny location with good access to water.
Blueberries need acidic soil, great drainage, and lots of organic matter in order to thrive and fruit well.
Acidic soil means a pH value of 4.5 to 5.5. If your soil is sweeter than that the shrub will be unable to take up the nutrients from the soil and you will have yellowing branches and foliage, plus little to no berries.
Have an area where rhodos and azaleas thrive? Are deep green in colour? Then you also have the perfect pH for blueberries.
Soil pH can be checked with an inexpensive kit available at most garden centres. You simply put a bit of soil into the vial, add some water, shake and let sit a few minutes, compare the colour of the solution in the vial against the colour card provided, and you will have a good approximate of your pH.
Dig a large hole for your plant, about 2 feet wide and 1 foot deep. Blueberries have shallow roots, so this has the organic matter in the top layers where the roots have easy access to them. If you are planting several shrubs, it is recommended that you either dig a wide trench or make a raised bed to house the plants in order to get the best results.
Add soil conditioners to the hole that are acidic, like composted pine or fir bark (sold in bags just like bark mulch), peat moss, pine needles, or leaf mould. Mix these conditioners with the soil that you removed from the hole. You might also be able to find a potting mix that is specially blended for acid loving plants, such as rhodos, etc...
The shredded, composted pine bark mulch adds great drainage plus amends and acidifies the soil as it breaks down. The peat moss or acidic potting mix provides the acidic soil conditioner and so the best 'soil' for your blueberries. Thus, the perfect mix for your planting hole contains both of these ingredients.
I would not use manure but compost is always a fabulous soil conditioner and great for top dressing/mulching around the shrubs.
Plant Your Blueberries in a Pot or Planter
If you do not have an ideal location, blueberries grow very well in pots and are also very attractive to look at. They have small glossy foliage, deep green in summer and red in fall, white or pink flowers in spring and summer, hopefully followed by loads of fruit. Very beautiful!
Again, you want to have acidic soil...
You would use the same conditioners mentioned above, do not use garden soil in pots or planters, it is too heavy, not porous enough and so you will have root rot issues.
The ideal mix would be contain shredded bark in an acidic potting mix, however just the potting mix will work as well.
Plant a one gallon shrub into a pot that is at least 12" to 14" wide. A two gallon shrub should go into a pot that is at least 18" to 20" wide.
Mulching your blueberries is highly recommended as it helps to retain moisture and keep the roots cool. It also keeps away weeds which is important as the blueberry has a shallow root system and is not good at competing with weeds for food and water.
The mulch should be topped up every two to three years, as it continues to break down, adding more organic matter to the soil, and thus helping it to stay fertile and acidic.
A mulch of three to six inches is best, but do not mulch the base/crown of the shrub itself or you will get stem rot and lose your plant. The mulch should be covering the feeder root system, keeping it cool and moist, so covers the entire lovely huge hole you made for your blueberry to grow into.
What to use for mulch? Composted pine or fir bark, pine needles, coffee grounds, compost, leaf mould....
You should test your soil pH and N-P-K every year preferably, but every two to three years for sure.
If your soil is getting too sweet, add more of the acidic soil conditioners listed above, like composted bark and leaf moulds, etc... as a top dressing. These will amend the soil as they break down.
Throw down a handful of nitrogen to the top of the soil each spring, in the form or blood meal or cottonseed meal.
Liquefied kelp or seaweed applied as a foliar spray once or twice a year is also a great organic fertiliser.
Compost makes a great top dressing, esp if mixed with coffee grounds or pine needles, etc... which are acidic.
Blueberries will suffer quickly from drought as they have such shallow root systems and are thus unable to dig deep for water.
They need at least an inch of water each week, and should have a good 3 to 6 inch layer of mulch to retain the moisture. As with all things, avoid watering the foliage, keeping the water at ground level, in order to prevent diseases.
Water is most important during fruit set (when you see the flowers) thru your harvest time, and then again in fall as that is when they set buds for next years fruit.
Potted berries will need water more often, watering as often as they dry out, depending on the elements.
You will not need to do any pruning for the first 3 years unless you have some damaged branches to remove.
After that, you will want to prune once a year, in late winter, for best fruiting.
Begin by removing any canes that are 5 years old and cut back the rest of the branches by about 1/3. Remove any week, little twiggy growth and suckers, plus any branches that have a lot of greying or other discolouration on them.
You will want to have 6 to 12 good pencil sized canes on a mature shrub.
The fruit will ripen over a two to five week period. Wait till the berries have turned a deep blue in colour and continue to pick as they ripen.
Your shrub should not fruit the first year that you plant it, in fact you should ideally remove flowers from the shrub as they form, allowing it to set a great root system in that first year.
Afterwards, you will get more and more berries as your shrub grows and matures. You shrubs will continue to fruit for about 20 years.
Blueberries are actually fairly pest and disease free. Your biggest issue will likely be the birds as they enjoy the delicious fruits as much as we do. This is easily handled by covering the shrub with berry netting.
Spraying your shrubs with a dormant oil/sulfer spray in late winter when you spray your fruit trees and rose bushes is a good way to prevent any pest or disease issues.
Recommended varieties for our area..
Early fruiting - Duke, Patriot, Spartan, Reka
Mid-season fruiting - Chippewa, Blue Crop, Northland, Hardi-Blue, Blueray
Late Season Fruiting - Elliot