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Safely Lowering PH of Potted Blueberries

Posted by lawanddisorder 6 (My Page) on
Tue, Apr 8, 14 at 11:32

I have a number of blueberry plants that I planted a year ago. At that time, I planted some in regular potting soil and added an acidic fertilizer to the top, per the advice of my local nursery, and planted others, after reading about proper blueberry soil, in a mix of pine bark, peat moss, and soil, and added that same acidic fertilizer mixed right into the soil before transplanting.
The plants looked a bit distressed early in the summer, but bounced back and looked healthy by the fall.

I gave that acidic fertilizer away, and now need to figure out a plan for maintaining proper soil and PH this year.

I use only rain water on the blueberries. I have some organic fertilizers that I would like to use, including worm tea, soluble ericoid mycorhizae, kelp and blackstrap mollasses, but I think I will still need to lower the PH.

I've read so many alternative methods of lowing PH my head is spinning. And I have to be even more cautious/conservative, because they are all potted and a little too much of something could have a hugely negative impact. Any advice to gently/safely lower the PH in containers for a home urban orchardist would be greatly appreciated!


Follow-Up Postings:

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RE: Safely Lowering PH of Potted Blueberries

Weak vinegar solution?

BTW. Do you know what the pH is now?


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RE: Safely Lowering PH of Potted Blueberries

Yeah you have to know the PH, that is a must. You could use Holly-Tone organic fertilizer. it contains sulfur, and will slowly lower the PH, but you have to monitor levels.
Vinegar is great for short term, but does not last, each time rebounding back to where it was before the vinegar was added. You can use a lot of methods, the key is knowing where you are at, and where you need to go to. Otherwise it's all a guess. Also you just can't add vinegar without knowing the PH of the water, you could overdose or underdose. You want water about a PH of 5, depending on water source, the amount of vinegar needed to achive that will vary.


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RE: Safely Lowering PH of Potted Blueberries

I wouldn't worry too much about the pH of the soil. The pH of the water is much more important. I have a few container blueberries planted in 511 mix that's a few years old now. They are growing like weeds and I have not once adjusted the pH of the soil. Adding white vinegar to the water has worked well for me. Test the pH of your water, and adjust it from there. Around 4.5-5 is a good place to start.


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RE: Safely Lowering PH of Potted Blueberries

That's pretty amazing as the bicarb load here is so high that adding vinegar to the water is like using a water pistol to put out a volcano.


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RE: Safely Lowering PH of Potted Blueberries

Over on the fruits forum where there some extremely experienced folks growing blueberries in containers, I don't recall anybody adjusting the pH in containers. In the ground, YES, but not in containers. It's all about the fertigation in containers. As long as you are using some well draining of peat and pine bark mix, there shouldn't be an issue. There are other ways to acidify water, and yes you are right about the bicarbs., but that just means you'll have to use more acid to neutralize. What's your Calcium Hardness where you are in MI? Mine is about 120 here, if I remember correctly.


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RE: Safely Lowering PH of Potted Blueberries

Ed, i can quickly think of several posters on the fruit forum that not only practice, but advocate adjustment/ maintenance of ph for blueberries they grow in containers. One does it via media adjustment only, others via media and water adjustment


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RE: Safely Lowering PH of Potted Blueberries

OK, I possibly stand corrected. I will do some research over there and see who is adjusting their container mix and how they are doing it. It's been a while. Just waking up after a long winter hibernation. At the same time it would behoove most to start their blueberry bushes out in the correct mix to start, and it would save a lot of future grief trying to adjust the mix. Throwing a blueberry bush into a container of potting soil is not the way to go. If I needed to adjust, agricultural sulfur would probably be the way to go. I'm into year 4 with my mix, and don't plan any adjustment anytime soon.


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RE: Safely Lowering PH of Potted Blueberries

I will be growing 4 plants in pots this year. My water hardness is 104. I guess I should not complain! I'll be using rainwater though. I already have 200 gallons stored.
The rainwater is close to neutral, I will have to keep an eye on PH.
I'm using a 1-2-1 mix of pine-peat-DE. I may adjust mix as year goes on. I like more peat because it is consistently low in PH. The DE (Diatomaceous earth) is neutral, it holds a lot of water, and aerates the soil really well. I need something that can keep the peat moist with less risk of it drying out. I think any mix no matter what ratio of pine and peat will work.


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RE: Safely Lowering PH of Potted Blueberries

Your mix sounds good, but your water needs help. The water won't acidify quick enough, and your plants will be drinking 7.0 water. 2 tablespoons of 5% white vinegar per gallon is a good start. Should bring the water to about a pH of 5. I would do some experimenting.


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RE: Safely Lowering PH of Potted Blueberries

Yeah most rainwater is more acidic, but so far ours is not. You know a side effect to having clean air :)
I use sulfuric acid. It only takes a few drops for 5 gallons.
Another product you can use is lemon juice. Works good too! I sometimes use vinegar, i don't want to put too much sulfur in pots. In ground, I'm not concerned, or as concerned. Still the rainwater is neutral, no bicarbs, so I really do not have to treat it. Yes, tap water has calcium 104 as reported. But the rainwater does not. I use acid in both for now, as I want the soil a touch lower. It's running at 5.8 right now.
I have 3 of 4 blueberries in. One more is coming Tuesday. So far they have never seen tap water. I captured plenty rainwater early on.
My 3 blueberries in ground are still very dormant. They are 3 years old and I expect a decent crop this year.
I expect a huge raspberry crop, a decent blackberry and blueberry crop. It should be a great year! Next year I will get ton's of peaches. Only a few this year.
I have 11 tomato plants going and about 20 pepper plants. They are doing very well. hardened off and all, but still too cold to leave outside. I exposed my tomatoes and peppers to yesterdays high winds, and they stood strong, using a fan inside really paid off! Anyway they are ready, but it's going to be a few weeks still before I can leave them outside. I have a cold frame they go in now.
Today they didn't even need the cold frame. it was near 70.


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RE: Safely Lowering PH of Potted Blueberries

OK, sounds like you are on top of it. That's funny, not much acid rain here either. We're expecting a big fruit crop. Another long cold winter. Good steady chill hours :-) Our strawberries and blueberries were almost overwhelming last year. Have had a couple of Southern Highbush blueberries over-wintering in the garage, and yesterday was their first day outside. 70F here too.


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RE: Safely Lowering PH of Potted Blueberries

The three blueberries I have in the ground are Northern, and the 4 in the pots are southern.Tthe southerns are all new this year, so no fruit for a bit. But the northern's Toro, Liberty, and Chandler produce decent berries for me.
Still young plants, each year harvest should increase for a few years yeah!


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RE: Safely Lowering PH of Potted Blueberries

If the mix is sufficiently acidic and you're using rainwater, why would you need to acidify the water? Or am I misunderstanding what you guys are saying?


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RE: Safely Lowering PH of Potted Blueberries

"At the same time it would behoove most to start their blueberry bushes out in the correct mix to start, and it would save a lot of future grief trying to adjust the mix."

Well said. That's why I'm going to nag the OP more about repotting rather than trying to adjust pH. :) As bamboo emphasized (and I echoed) in the thread that you started in the fruit forum, your bushes will be much happier (and caring for them much simpler) if you repot them in a more suitable mix while they're still dormant. If they're already blooming and leafing out, then I guess you're stuck with trying to manage the pH for another season.


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RE: Safely Lowering PH of Potted Blueberries

shazaam, The rain water has a fairly high pH, and overwhelms the short term acidifying ability of the mix. We get a lot of rain here and the rainwater doesn't hurt them, but when I do water, I make sure I give them a decent acid drink.


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