[Grubbypaws]

In 2017 I repotted my Spartan blueberry bush in a new 55cm terracotta colour plastic pot using ericacious compost and mulching with pine needles. Since that time it has been entirely unproductive although healthy looking. This year I measured the pH and surprisingly found it to be high so I added sulphur chips as advised by someone on this forum. The chips have not lowered the soil pH at all.

I did notice that when I watered this pot the water drained out an orangish colour and I was wondering if the dye used for this pot may be hindering my attempts to bring the pH down and into the correct range.

Any one any thoughts on this?

[Gardener and Rabbit]

Hi Grubbypaws, here are my thoughts:

- I think if the plant looks healthy, that's probably the best sign that what's in the pot (compost, pine, needles, sulphur chips) is all ok. I haven't heard of a plastic pot changing the pH, and it would probably be quite hard for a pot to do that given the volume of compost vs pot.

- Have you tested the pH of the water that you're using when you water your blueberry, you may be watering it with a hard water?  I use rainwater on mine, collected and stored in plastic guttering/water butt.

- Have you checked that the pH test is working accurately, perhaps test something that you know should be neutral to mildly acidic, such as distilled water, to see that it gives the correct reading.

G&R

[Grubbypaws]

Thanks G&R
It is watered with rainwater.
Ericacious compost + ericacious feed + rainwater + pine needle mulch should surely do the job!
I will test the pH meter as you suggest but I suspect that it may be correct; I bought it recently as the bush hasn’t produced fruit since being repotted early in 2017.

[Gardener and Rabbit]

I can't see any problem with your growing mix! 

I'm growing Top-hat in large plastic pots using ericaceous compost, they get an occasional handful of coffee grounds as a top dressing, and nothing more, and they still fruit well after several years. Very similar to your method.

It might be interesting to take a pH reading of your rainwater, see what that reads?

[JayG]

Just a few thoughts:

1) Don't think there's any way that a plastic pot could influence pH either way.

2) Sulphur chips do work, but very slowly as they have to be broken down by soil organisms to produce acidity.

3) pH meters seem to be notoriously inaccurate unless you  pay a lot of money for them - simple chemical pH test kits are cheap and more reliable (albeit more fiddly.)

4) When you say it's unproductive, do you mean the flowers don't set or that there are very few flowers?
Is it the only blueberry bush you are growing?

[Grubbypaws]

Thanks JayG and G&R

It is one of 4 blueberry bushes grown in the same fruit cage and watered from the same water butt. The other three are covered in blueberries 

The only difference with my Spartan is that it has been repotted and is in a different make of terracotta coloured plastic container.

It hasn’t produced fruit since being repotted and that is why I bought the pH meter. The meter reads nearly 7! I do have a soil testing kit but I am not sure how to get a sample from around the roots without doing harm. The pot has been top dressed with ericacious compost and sulphur chips so I doubt a surface sample will be of much help.

I was not at home when it flowered so I cant answer the last question although I suspect that there were very few flowers as that is what happened last year. The bush is otherwise very healthy with nice new groth appearing.

[JayG]

I bought a 3rd blueberry this year because last year one of the other two had very few flowers but lots of leaves, and the other lots of flowers (and fruit) but very few leaves. This year they did exactly the opposite, so overall I'm pretty clueless I'm afraid. 

It could just be yours needed a year to fully recover after its re-potting (the flower buds are formed before the end of the year to open the following spring.)

[moose]

Agree with JayG. After I repotted a blueberry it took a full year to recover. I bought a pH meter some years ago and it reads pH7 no matter what you test, acetic acid, distilled water, caustic soda all pH7.

[Goosegirl]

Instead of using a pH meter I'd try getting a water test kit from an aquarium supplier. They consist of either paper strips you dunk into a small container or some have little oblong plastic containers that you fill up with your water and add a few drops of a chemical. Both will change colour and there's a guide to tell you what the pH is accordingly. First test your water, then use a pencil or similar to get a small bit of soil from a hole in the base of the pot. Add it to the water you just tested, give it a shake, leave for a couple of minutes then test again.