This week I transplanted my two Brigitta blueberry bushes into much larger pots, which will be their permanent homes. As I indicated in earlier posts on blueberries, these plants love acidic soil but it is neither practical nor adviseable to try to turn a whole bed into an acidic environment. If you actually manage through vast amounts of chemical interventions, to get your garden soil acidic, you’re going to have ruined the soil for most plants because not that many appreciate low pH. More likely, you will never get the acidity to remain stable because the natural soil, tap water and time will cause the pH to revert to what it was naturally.
TL;dr: Plant your blueberries in pots, unless your garden soil is naturally acidic.
I got two large concrete pots (painted on the outside to look terra-cotta), that are tall and wide enough to give the bushes enough room to grow over many years (blueberry bushes can survive for over 20 years).
Soil mix ingredients
You can buy a pre-mix for acid loving plants like ericas, azaleas etc or make your own like I did. This post isn’t sponsored by Cultera. This stuff happens to be what my local nurseries had available 🙂
Perlite (not vermiculite)
Peat (Canadian, coco, loose or solid are all fine)
Ammonium sulfate (acidic fertiliser) or Organic fertiliser for azaleas, etc
Buckets of rainwater
1. Ensure the pots have drainage holes. Line them with stones & if you have some shade cloth or similar type of mesh, put that over the stones. I got that tip from the nurseryman who explained that it prevents the soil from compacting over the stones. Add 1/3 each of the acid compost, perlite and peat in layers. Doing that in layers ensures a more even mix.
2. Mix the layers well until the pot is almost full. I continued adding to the top, after the pic was taken, ending up just above the painting line. Then add the Ammonium sulphate as per manufacturer’s instructions. Mine indicated 60 grams per m2, were to be added and mixed into the top 150mm of the soil. If adding an organic, soluble fertiliser instead, leave that for the very end after your plant is in the pot. Don’t add both at the same time, as plants can get fertiliser burn. Rather add the chemical one to start, and dose weekly with the organic type, or ensure you use a slow release organic.
3. You can then make some room and place your plant in the pot. I didn’t break up the roots because they are very fine and shallow. I just watered them well, an hour before repotting. On a whim I decided to add earthworms to the pots. They were easy enough to find in my garden, but if you live in a flat or complex, I guess one can buy them too. I will be feeding the blueberries with manure, so I hope that will be good for the worms too. One of them had a yellow saddle, so it should make lots of babies in there. Just in case there wasn’t enough organic food, I added a few pellets of Neutrog Bounce Back. It’s slow release, so there isn’t much danger of over feeding the plants.
4. Water the plants well with the *rain water. If water comes out of the bottom of the pots, you’ll know that the drainage is fine. Mulch them with pine bark chips. They are a great way to conserve water, keep roots cool, they look great & are also acidic. There you have it! “Job’s done!” – Warcraft 2, Orc peon voice.
*Mixing vinegar with tap water isn’t a very effective or sustainable way to keep the soil acidic. Soil microbes metabolise the vinegar so fast, that it loses effect within a day. If you have trouble collecting rainwater, add some sulphur powder to the soil. It’s slow acting but works well.