Growing Blueberries

Blueberries are classed as an antioxidant superfood. They contain antioxidants, phytoflavinoids, are high in potassium and also vitamin C making them a great healthy food choice with a great flavour. Pam loves blueberries and has them regularly on her breakfast, they also freeze well so make an excellent option for us to grow on the allotment. They do require full sun, which was not a problem on the allotment, but the soil is not suitably acidic. They require soil with a pH of between 4.5 and 5.5 but experience tells me that our plot is more than likely neutral to slightly alkaline (I have not tested it yet but will be doing in the not too distant future). If your soil is not acidic enough then there are many ways you can still grow blueberries, the easiest of which is to grow in containers filled with ericaceous compost. This could simply be a large plant pot or maybe a raised bed. It maybe possible to change the pH level of your soil by adding minerals. Soils can be made more acidic by the addition of sulphur of made more alkaline by adding lime. The down side to this is that changing the the pH level of the soil affects the surrounding soil and the surrounding soil will over a short period of time neutralize those changes. This can to a large part be resolved by using a barrier around the area in which you intend to change the pH. For most people a plastic barrier of about 60cm (2ft) deep would be suffice. On the allotment we have been told that we are no longer allowed to use plastic in this way, which is understandable given the amount of plastic that I and others are constantly digging up.

Our Blueberry Bed

Construction

What I have done to create our blueberry bed is collect 26 2x2 concrete flags which were given away on Trash Nothing and Gumtree. I have used these flags end on to create a barrier around a bed 6m x 0.9m (20ft x 6ft). The bed contains three blueberry plants spaced along the centre 2m apart. The area should be large enough to create a stable pH level within the bed and the flags giving enough protection from/to the surrounding soil. Construction was heavy work, made worse with the weather conditions at the time but I am happy with the finished bed. Below Left When digging the hole to put the flags in, I used a post holing spade and post hole digger (spodgers) to keep the hole narrow. This makes it much easier to get the flags firmed, in though a wider hole may have made it easier to position the flags. Below Centre shows the flags partially back filled. It is important to use a tamper to firm the soil around the base of the flags. A pick handle worked perfectly for this. Below Right shows how I lowered the flags, positioning them up to the line.

Testing and

correcting the pH

In order to know what the pH reading for our soil is, we need to test it. The best way to do this is to use a home pH test kit. These are relatively cheap and can be purchased at most garden centres or on line. They will require a sample of soil (or several) mixed with water, then depending on the type of kit, you will either use a special paper tab that changes colour when dipped into the water or add a chemical to the water which changes the water colour. You then check the resulting colour against a colour chart to get a reading of the pH level. These are relatively accurate and easily good enough for home use. Another way to take your readings is to use electronic pH meters, the cheap ones available at garden centres and online are not reliable and in my experience not worth bothering with. Once you have your readings, you can then work on a plan to correct the pH level to that what is required for growing your blueberries. I plan to use the figures taken from the RHS    for acidifying   soil . I am likely to require around 500g per square metre of sulphur to get something like the acidity level I am wanting to achieve. This is slow acting when the soil is cold and is best added in spring as the soil warms up. I will be removing the mulch then digging in half the amount I think I will require. Then I will replace the mulch. After leaving the bed for a few months to settle I shall re-test the pH and repeat the process as necessary, though future applications of sulphur will be hoed in rather than digging in, so as not to disturb the roots. This may take several months or years to get what I am aiming for and will require regular pH checks and correcting. I will add the results to this page as I go. Note that clay soils can take a lot of acidifying materials e.g. sulphur or iron sulphate. If your soil contains free chalk or lime you may not be able to treat it and in this case containerisation will be your only realistic option. You can find more detailed information on pH testing on the RHS website by following this link.

Birds Love berries

Birds need to eat and will happily take all your blueberries, so it will be necessary to protect from the birds once they start producing fruit. Protecting the blueberries with netting is all that is required to prevent the birds getting to the fruit. It is possible to buy a fruit cage and there are many options available on the market. While the bushes are small they can be protected by draping netting over canes topped with bottles or plant pots and weighed down at the edges using bricks. It is important to keep the netting taught so that the birds do not get trapped and killed by the netting. I plan to build a fruit cage around the bed that I have made. Currently I am looking at the various options available including a building a wooden frame or using an old marquee frame bought cheaply from Ebay. Once I have worked out what I going to do, I will add the details here.