Acidifying soil for blueberries?

Mr_D

Hi there,

We started growing two blueberry bushes in large pots a couple of years ago. After a very good harvest on the first year, one of the bushes died, and the second one produced very few fruits on the second year. The likely problem is that the pH for the soil had gradually increased to 6 or even 7. I suspect this happened when we watered the plants with tap water during a dry period in summer.

I tried various ways to re-acidify the soil, including replacing the top 10 to 20cm of compost with peat moss, and more recently mixing in some "flower of sulphur" (hard to find here, had to get it shipped from the UK - if you know a supplier in/near Co. Dublin please PM). Unfortunately the pH has not started going down just yet. Has anyone managed it, and if so, how long does it take?

More recently, we bought two more blueberry bushes which we planted directly in the soil, in our allotment. The planting was done in a hole of c. 80cm diameter filled with ericaceous compost (Shamrock brown gold), so acidity should be fine in the short term, but I expect it to go up over time. Should I just mix some flower of sulphur when needed to keep the acidity down? Has anyone experience of growing blueberry bushes directly in the ground and if so what can we do to slow down the alaklification of the soil?

Thanks for your advice,
Mr_D

monkeynuz

Mr_D wrote: »

Hi there,

We started growing two blueberry bushes in large pots a couple of years ago. After a very good harvest on the first year, one of the bushes died, and the second one produced very few fruits on the second year. The likely problem is that the pH for the soil had gradually increased to 6 or even 7. I suspect this happened when we watered the plants with tap water during a dry period in summer.

I tried various ways to re-acidify the soil, including replacing the top 10 to 20cm of compost with peat moss, and more recently mixing in some "flower of sulphur" (hard to find here, had to get it shipped from the UK - if you know a supplier in/near Co. Dublin please PM). Unfortunately the pH has not started going down just yet. Has anyone managed it, and if so, how long does it take?

More recently, we bought two more blueberry bushes which we planted directly in the soil, in our allotment. The planting was done in a hole of c. 80cm diameter filled with ericaceous compost (Shamrock brown gold), so acidity should be fine in the short term, but I expect it to go up over time. Should I just mix some flower of sulphur when needed to keep the acidity down? Has anyone experience of growing blueberry bushes directly in the ground and if so what can we do to slow down the alaklification of the soil?

Thanks for your advice,
Mr_D

Flowers of sulphur can be bought from Johnstown garden centre as yellow sulphur.

Ericaceous compost and ericaceous plant food such as sequestrene or any food for azalea/rhododendron etc.

Mr_D

Thanks monkeynuz, good to know.

monkeynuz wrote: »

Flowers of sulphur can be bought from Johnstown garden centre as yellow sulphur.

Ericaceous compost and ericaceous plant food such as sequestrene or any food for azalea/rhododendron etc.

Re. Ericaceous plant food - we had bought some but brought it back because we were unsure if it was "safe" for use on fruit bushes. AFAIK no one would eat azalea / rhododendron so I was looking for a product sold as suitable for blueberries (or other fruit / veg). Or maybe we are too cautious and the regular ericaceous plant food is just fine.

On a related topic, I took a measurement of the water at the allotment (that comes from a nearby stream) and its pH was 7.5 to 8. It's possible to acidify it to 5 using vinegar, but I am not sure if the problem is only acidity, or acidity and the presence of lime.

monkeynuz

Mr_D wrote: »

Thanks monkeynuz, good to know.



Re. Ericaceous plant food - we had bought some but brought it back because we were unsure if it was "safe" for use on fruit bushes. AFAIK no one would eat azalea / rhododendron so I was looking for a product sold as suitable for blueberries (or other fruit / veg). Or maybe we are too cautious and the regular ericaceous plant food is just fine.

On a related topic, I took a measurement of the water at the allotment (that comes from a nearby stream) and its pH was 7.5 to 8. It's possible to acidify it to 5 using vinegar, but I am not sure if the problem is only acidity, or acidity and the presence of lime.

Sequestered iron or azalea food preferably the liquid one should be fine in fruit sequestered iron definitely is.

Or get the seaweed based iron feed that will also be suitable.

I always use sequestrene but it seems to come and go availability wise.

Gruffalo22

I have 4 blueberry bushes in the ground and doing well - acidity is fine. I lined the sides of the hole with plastic to prevent alkaline water from the rest of the garden seeping in and raising the PH. There should be no plastic on the bottom to allow for drainage

Mr_D

Hi Gruffalo22,

Many thanks for this. My 2 potted plants are definitely doing better (after using the flower of sulphur to re-acidify and the sequestrene as recommended by monkeynuz on the forum).

In the meantime, I did an experiment and planted 2 new plants directly in the soil in the allotment. But the plants started suffering after only a couple of weeks. So I plan to dig them out this week-end. I will take a similar approach to the one you have recommended, but using pots instead of plastic bags (so burying the pots in the soil to prevent the contamination from nearby untreated soil, but with multiple large holes at the bottom to allow for good draining). So same approach but slightly different implementation. Thanks for the suggestion.

Many thanks
Mr_D

Gruffalo22

Just bear in mind that the roots would need an area the width of a barrel in the long term once fully grown. I dug a hole approx a foot and a half wide and lined with polythene