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Do Blueberries Still Need Acidic Soil If Soil Fertile?

Posted by Andrew7a 7a (My Page) on
Tue, Oct 29, 13 at 18:44

I just planted blueberries in my garden late this past summer, more or less on a whim, because I saw that Home Depot was getting ready to throw their unsold plants in a tip to make space for their fall lineup. I did a little research and found that blueberries like acidic soil because a low soil pH makes certain nutrients - Fe, Mn, Zn Cu, Co, and up to a point, P - more available. I had my soil tested and it turns out that I live in an area with some of the most fertile soil in the country. At a pH of 6.7, my garden's soil already has above optimal quantities of available major nutrients for blueberries, and has an abundance of available micronutrients like Iron and Magnesium. I have begun applying a mixture of powdered sulfur and dissolved ferrous iron sulfate to my blueberry patch as instructed by the soil testing lab, but I am now wondering if I should continue doing so. If my soil is providing an overabundance of nutrients to my bushes at a pH of 6.7, and lowering the pH will only increase the availability of those nutrients, might this not actually be bad for them?


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Tue, Oct 29, 13 at 18:50

Follow the labs instructions for blueberry. Your plants might be OK at 6.7 but lowering the pH to 5 or slightly lower won't hurt and will probably help.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

The PH is so important, but agree an over abundance will not help them. The sulfur won't even work probably till next spring. I would not add the iron sulfate if you have plenty of iron., I would test PH in spring, then add more sulfur to get it to 4.5 to 5.0. logarithmic so your soil need to be 170 times more acidic than it is before you added anything. Compost, or garden soil do pretty much nothing for blueberries, you need peat and pine bark fines. Without it, it is hard to maintain PH. That mix is pretty nutrient poor, so organics like cottonseed meal or Holly-Tone needs to be added. Or with Ammonium sulfate, which the plants love too! If synthetics fits your needs better. Don't use compost or garden soil, it can increase PH too much. Mulch with pine bark or pine straw. Don't let it dry out, keep moist, but not wet. Infrequent long waterings are better than frequent short ones. Lot's of sun too.
So to sum it up your PH is way off and you put it in completely wrong type of soil. Unless both are corrected the plant may live, but not thrive. If you correct it the plant will grow 4-6 feet tall and produce pounds and pounds of blueberries.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Fruitnut is absolutely right. The answer to your question is yes, they'll do best in acidic soil (fertility aside). The crux is that your soil isn't necessarily "providing an overabundance of nutrients to [your] bushes at a pH of 6.7." Those nutrients might be present, but, if the pH isn't right, your plants will have more difficulty accessing them. That's not to say that it's impossible to grow blueberries at pH 6.7 -- just that your odds of success will be higher if your pH is lower.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Andrew,

Think of it this way.....if your refrigerator and cupboards were all packed solid with food but your mouth was sewed shut would you get enough to eat?

The lower PH allows the plants to take up what they need. You could have the richest soil on earth but if the PH gets too high the plants decline.

I have to disagree with Drew when he says "Infrequent long waterings are better than frequent short ones"

While that is true for most plants BB are shallow rooted so more frequent applications of water keeps the upper levels of the soil most where all their roots are. Mulch helps a ton.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Thank you all for replying. One of the reasons I am asking this is because the soil analysis I had done shows the quantities of nutrients in my soil that are in available form for uptake by plants, as opposed to the quantities of the elements (N, P, K, Fe, Ca and Mg) bound up in the soil. (If they had shown the quantity of elements present, iron would have been through the roof because I'm on red clay alfisol.) The only nutrient I was instructed to provide was nitrogen, as a matter of course rather than to address a particular deficiency.

I don't have any experience yet growing blueberries, but in the soil I'm working with, I've been growing mountain laurel, rhododendrons, hydrangeas and azaleas. All four of them grow vigorously and flower profusely every year. I've never fertilized or done anything to the soil other than keep it mulched with leaves every autumn, and the biggest challenge these plants pose for me is keeping them in check. I thought this might be an indication that my soil already provides ample nutrition for acid loving plants, even at a higher pH than what they typically need in poorer soils.

It can't hurt to find out, I guess, what will happen when I lower the pH. I've put down the first half of the recommended amount of sulfur. I guess I'll just have the soil tested in the spring to see what the pH does and gauge how my bushes are responding.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Wed, Oct 30, 13 at 11:13

Andrew if all those other plants are thriving then your blueberries will also. With that information I'd change my suggestion and tell you to wait on adding more sulfur. See how the blueberries grow then you can decide.

Next spring is too early to take another soil test. The sulfur takes longer than that to show full effect. The bacteria that convert it to sulfuric acid won't do much over winter.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Who knows -- your blueberries might do OK. I've read anecdotal reports from growers who do have higher than optimal pH and do just fine, but all of the university research that I've seen says otherwise. Problems usually arise because of blueberry bushes' somewhat unique adaptations. For one, they don't grow root hairs. In most other plants, root hairs secrete an acid that makes certain minerals soluble. Blueberries, on the other hand, depend on soil pH and microbiological action to make those minerals available. They're also not very efficient users of nitrogen in the form of nitrates. In the nitrogen cycle, organic forms of nitrogen begin as ammonium and then are converted to nitrites and then nitrates (I think I have that right) by bacteria. Those bacteria only operate at higher soil pH, though, so they're not generally present in low pH soils. Therefore, in low pH soils, nitrogen is more commonly available as ammonium. It's not surprising, then, that blueberries are very efficient users of ammonium and not so good with nitrates.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

  • Posted by ericwi Dane County WI (My Page) on
    Wed, Oct 30, 13 at 11:28

A healthy blueberry plant will have deep green leaves, during the growing season. They will be a lighter green when they emerge in the spring, but the leaves should get darker in several months. A healthy plant will approximately double in size every year, for the first 2 or 3 years. On older plants, you can tell that they are growing because the branches will get too dense, and the shrub will have to be pruned. If you are able to grow other ericaceous plants with good success, then you should be able to grow blueberries using the same methods. Since blueberries have most of their roots near the surface, it is possible that the mulch you are using is feeding your plants as it breaks down. The soil pH might be near optimum where the roots are growing. A pH test done on soil taken from a deeper location could indicate alkaline pH, even though the pH at the surface is more acidic. As you have shown, the ericaceous plants can grow successfully in a thin layer of broken down leaf litter over clay base soil with pH that is higher than optimum. The mulch you are using must be having a positive impact on your blueberry shrubs.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

If you decide to stop adding sulfur and take a wait and see approach, you might want to try a thick mulch of pine bark fines. While the fines won't necessarily lower the pH of the soil underneath, the horizon where the two meet will likely be somewhat acidified as the fines break down. If the mulch is thick enough, your plants will also spread roots into it and potentially find harder to get nutrients that way, especially if you incorporate an organic fertilizer into the mulch (but don't overdo it). The mulch will also help to keep the soil cooler and damper, both of which are advantageous for blueberries' shallow root systems.

EDIT: I see that Eric said much the same thing while I was working on this post. I definitely second his opinion...

This post was edited by shazaam on Wed, Oct 30, 13 at 11:38


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

The other plants listed even though are acid loving, they grow fine in basic soils, unlike blueberries. If your hydrangeas flowers are pink, then the soil is too basic for blueberries. The deeper the blue color, the more acidic your soil. Some of the new hybrids are multi colors and tell you little about the PH, but the old fashioned ones are great indicators of soil PH.

This post was edited by Drew51 on Wed, Oct 30, 13 at 12:19


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Hmm, I'll see if I can find some pine bark. It seems like it's worth creating a test plot.

I'm tempted to believe that my mulching regime is part of the reason that my plants do well. As I mentioned, I currently mulch with leaves (shredded, mostly maple, tulip tree, oak, sycamore and shag bark hickory), and lots of white pine needles. I always figured this is the cheapest way to go and it mimics how nature works in this part of the world.Then again, it could be that plants do well because the soil is just very fertile. Farms in my area produce some of the highest yields in the state for corn, wheat, alfalfa and every other common crop. It actually seems like a huge waste of productive land to see so much suburban sprawl replacing farms around here (in Bucks County, PA).

Drew - yes, my hydrangeas bloom in various shades of pink.

Shazaam, come to think of it, I did notice that the blueberry bushes' roots didn't seem to have any root hairs on them. I didn't think anything of it at the time, but what you said is interesting and it sort of reminded me of something a naturalist told me when I was in the Boy Scouts. He said that a lot of the plants that do well in the PA mountains (where our camp was) would love to live in the more fertile lowlands, but they aren't often found there because other more aggressive plants simply outcompete them. According to him, many plants that thrive in the mountains live there because they can eke out an existence where other plants can't. Maybe blueberries are like that in some respects - they grow where they do because very few other things can handle what they can tolerate.
I really appreciate everyone's input!


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"Drew - yes, my hydrangeas bloom in various shades of pink. "

Watch them turn blue with the addition of sulfur. No need to test PH, you have these plants! Apply an equal amount of sulfur to them and the blueberries. Once a nice blue, you're good! Really this would be a great indicator where you are. Give 6 months for sulfur to work. Reapply every 6 months as needed by color.

At my cottage we also have very rich soil from an old growth forest. The soil is black as tar. But the moisture, shade from very tall trees and water front conditions (it's an island), make it an extremely hard environment to grow anything. I have been struggling to find plants that work. I have found some. Mostly wild plants, dogwoods, and bamboo.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Drew - Blue hydrangeas should be fun to see next year. I had too much pink going on in this part of my garden anyway.

It's handy that I have my hydrangeas, rhododendrons, mountain laurel and azaleas all growing in the same general area of the garden because it was purely an accident I made back in my noob days. The BB bushes are right next to the rhododendron so they should make decent neighbors.

I was wondering though, since non-acid-loving plants border my blueberry patch on one side, how mobile is sulfuric acid in soil?. Is it going to stay put, or is it going to diffuse all over the place? If it's the latter, I should probably shuffle some things around so I have more acid tolerant plants next to the blueberries on that side.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Composting is an acidic process (although the outcome is usually fairly neutral) and I believe that as mulch decomposes it creates a very narrow band of acid soil at the surface where adequate iron can become available even if the soil is still close to neutral. This would explain why certain ingredients like pine straw are often incorrectly assumed to acidify soil.

I'm one who's seen thriving mulched blueberries in mid 6 pH soil- several different varieties in such sites. I don't believe any research has been done to confirm or disprove my theory because mulching usually isn't viable for big commercial operations and almost all agricultural research in this country involves large scale commercial production.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

I think the sulfur will stay put. Just be careful with it. Also keep us updated on how it goes. You seem very observant. I guess I would not change soil, but I would add sulfur, even if they can grow in current soil, it will help them.
Your observations will be valuble info for all of us.
Some blueberries can grow about anywhere, but not all.
Sunshine Blue seems like a super hardy blueberry that can tolerat higher PH's. I don't know of any others? Again though best results no doubt will come with acidic soil. You don't want to just grow them, you want them to thrive. As stated by others in this thread, and my observations too, is when in the right PH, they tend to double in size each season till full grown. Mine went from 2 feet to 4 feet tall this year. Strong thick growth.

This post was edited by Drew51 on Mon, Nov 4, 13 at 0:12


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

I will certainly give a follow up report. For the record, I've probably put enough sulfur and iron sulfate on the soil to lower its pH, eventually, to around 6, give or take depending on what kind of buffer all the leaf litter and organic material in the soil winds up providing.

The particular varieties I have are Bluegold and Elliot. Apparently these bushes grow well in places that get really cold winters. If I hadn't gotten these bushes on a whim to save them from the dumpster, I might have gone with varieties that do well in the South, actually. Unlike most of the rest of Pennsylvania, I'm in zone 7a, and places only 20 miles or so south of me are in zone 7b. The climate here is more like the climate in Virginia or Tennessee - we almost never have a winter month with an average temperature below freezing. If these highbush blueberries need Michigan style cold, they aren't going to get it here. Hopefully this won't be a major complication.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

My sister grows highbush varieties in coastal CA and several growers south of you have productive stands of highbush varieties that have reported on their efforts here. I'm sure they will do fine.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

The pH limitation applies to the blueberries. They will struggle to be able to take up those nutrients at a pH of 6.7. I'd do pots or risk losing your plant$. Get that pH below 5.5. Though fruitnut is right, if you can actually grow those acid living flowers successfully then I'd suspect your pH is incorrect and is actually lower than thought. You don't say where you live. Rabbiteyes reportedly will grow in a slightly higher pH than the others.

Here is a link that might be useful: Southern Highbush Blueberry Response to Mulch


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Once you have your first crop of blueberries, small though it may be, you will be bitten by the blueberry bug that makes you keep planting more and more varieties. So don't worry about what these first two varieties are that much, you'll soon have many more.
Northwoodswis


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

I am looking for a recipe for soil for blueberries in a raised bed. Native soil is black and a heavy clay content I am old school and never learned about PH and soil testing & I probably should. Anyway if someone could give me an idea of what type of soil mix I would use. The beds are 4' X 4' X 1' Thanks in advance for the help


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

A blend of pine bark fines and peat moss should work well for you. The exact ratio isn't really all that important, and you could certainly grow in one or the other exclusively. I like bark because it's inexpensive and takes a long time to break down, but the addition of peat improves water and nutrient retention.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

I find this thread interesting. It seems like several who participated failed to note the vigor of your rhodies. Can someone give me a single reason why they can thrive in a nearly neutral soil and blueberries cannot? You probably never needed to add sulfur for your blueberries and I wish you'd try to grow a plant outside the sulfur treated area and let us know how it does.

Good luck in trying to convince anyone that blueberries can thrive in soil with a pH in the 6's. I've been trying to do that for about 20 years. People talk about research but research is limited to the narrow conditions of the study itself. Every soil is unique and mulching can completely alter availability of nutrients in ways not yet sorted out.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

I grew up in the PNW. Rhodies and Azealias were everwhere. Even wild native varieties of one or the other at higher elevations. Hydrangeas were naturally light blue. And yet, anyone that was serious about bb's grew them in windrows of modified OM - usually sawdust with sulfur as sawdust was so abundant from all the saw mills. The soil that was 'fine' for other ericaceous plants was not optimal for bb production. It needed help. So while the Rhodies are a good indication in the right direction, it didn't mean it was within the optimal range.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

The way I see it, it is not an "all or nothing" proposition as it sometimes is portrayed. Ok at 6? Probably. 6.5 is marginal and needs special circumstances? Perhaps. But just because 6 in certain conditions is ok doesn't negate the favorability of other conditions, or the possibilibilty of more optimal conditions. Why not aim towards the mid range of what has been proven over time to be acceptable? Doesn't have to be an all or nothing that "must" be under 5.5, or "doesn't need to be below mid 6".


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"People talk about research but research is limited to the narrow conditions of the study itself."

That's a very good point, and, before applying pounds and pounds of sulfur in an attempt to radically alter soil pH, I can see the value in experimenting first in order to determine if it's even necessary. That being said, a raised bed (or mound) seems a reasonable compromise, especially if you have concerns about the suitability of your native soil. You can skip the sulfur, fill the bed with a proven and predictable mix, and, given proper care, be reasonably well assured that your blueberries will be happy and healthy.

This post was edited by shazaam on Fri, Feb 21, 14 at 16:27


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

On raised beds peat is what lowers ph pine bark will not so add more peat than pine bark IMHO. Both are great though!
I also use some garden soil as if you use all organic and no soil eventually all of it will decompose.

"I find this thread interesting. It seems like several who participated failed to note the vigor of your rhodies. Can someone give me a single reason why they can thrive in a nearly neutral soil and blueberries cannot?"

Yes, BB are acid dependant and rhodies are acid tolerant, they don't need it for uptake of nutrients like BB's.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"On raised beds peat is what lowers ph pine bark will not so add more peat than pine bark IMHO."

That's not actually the case, Drew. Peat has a pH of approximately 4.5, and pine bark typically falls in the 4 to 5 range. Regardless, if you're growing on top of the native soil rather than amending it, you're not really lowering the pH anyway.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Shazaam, yeah I was thinking how peat was just better. i think you pointed me to this study, which was good to see the PH of various mixes.

Here is a link that might be useful: Blueberries in Pots Project


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Drew, I don't understand, rhodies are the same in their need of free iron as blueberries, they just thrive in slightly higher pH conditions (don't require as much iron). At least as I understand it, for all acid loving plants it's primarily about iron although the ability to take in ammonium over nitrate is also in play.

The expert opinion is that rhodies shouldn't grow with excellent vigor in a near neutral pH. Do a search- the experts just push ideal pH for rhodies up a half point above BB's.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

When first growing Blueberries,I planted three Dukes in the ground near a carport with a concrete slab.After adding more to the collection,some in pots and others in the ground,the Dukes weren't growing as well as the others,especially the ones in containers.
I thought that the concrete may have been leaching too much carbonate,which may have been the case, and transplanted them into pots.They have about tripled in size.
All the Northern Highbush in containers are about four times bigger that the ones in ground.
I do use Sulfuric acid through a drip system on all the plants and when planting both container and ground,a Conifer bark/Peat moss mix is used.
I do have some Sunshine and Bountiful Blue,Southern Highbush planted in the ground that are fairing better than the Northern ones in ground.
The last time I measured the ground pH,it was with a cheap meter and was about 6.8 not treated with Sulfur.
The photos are a Bluecrop that has been in the ground for at least two years and one of the Dukes that came out of the ground.The Bluecrop looks somewhat like the Duke did when in ground. Brady

Bluecrop
 photo Image499_zps5e2bc538.jpg
Duke
 photo Image500_zps4ee88477.jpg


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"Drew, I don't understand"

I think it's pretty clear they grow fine in basic soil, whereas BB's do not in my experience. But I must admit I don't grow these flowers. I do know that I hear about BB failure all the time though. It seems many have problems growing them.
Best to grow all these plants in an acidic environment for optimal growth and health.

This post was edited by Drew51 on Fri, Feb 21, 14 at 21:18


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Thanks for all of the input I read the sturdy and like the sound of the coir peat mix till I researched the coir, PRICEY Is there someplace where one can find this at a reasonable price?


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Coir might be fine for blueberries, but the CSU Blueberries in Pots Project's soil mix experiment appears to be incomplete -- there's no info whatsoever about how the plants fared in the various mixes (just initial pH measurements). Furthermore, I find it telling that, for the greenhouse forcing experiment, they used a pine bark based mix (80% bark/10% peat/10% perlite). That's no surprise, really, because bark has proven to be an excellent substrate for growing blueberries.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

They probably didn't use coir because it is expensive. Pine bark is great. Coir though has proven to breakdown slower.It will last a year or two longer. An excellent product is coconut husk chips. It will last a lot longer than pine bark fines. So to me has a an advantage in pots. A huge disadvantage is price.
I bought some coir on Amazon, I bought three bricks so postage was free.

Here is a link that might be useful: COCOTEK 5KG BAIL


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

The husk chips are very expensive, and I have a local source for pine bark fines. So i will continue to use pine. I wouldn't mind trying the husk chips though!

Here is a link that might be useful: Coconut Husk Chips 50 Gallons Bale


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Opinions are like....noses :) Everybody has one.
Some think the worst thing you can use is peat moss and pine bark

Here is a link that might be useful: Pine Bark & Peat Moss Issues


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

  • Posted by ericwi Dane County WI (My Page) on
    Sat, Feb 22, 14 at 10:09

I have successfully grown blueberries in our native soil, high in clay, with pH around 7.6, after the soil was amended with compost made from shredded maple tree leaves. This was a Norway maple, not a red maple. Red maple leaves are thought to be toxic to blueberries. I also use agricultural sulfur to lower soil pH, and small amounts of Schultz Plant Food-acidic formula.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Eric, did you incorporate sulfur at before or after planting? What are you pH readings now?


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

  • Posted by ericwi Dane County WI (My Page) on
    Sat, Feb 22, 14 at 14:34

When planting blueberry shrubs here in Madison, I dig the hole, put 6 ounces by volume of sulfur in the bottom, where it stays, not mixed in. Then I fill the hole half way with peat, add some dirt, and mix the two thoroughly. The shrub goes in, and gets watered immediately. I add some more dirt to the top as needed, and an additional 6 ounces(by volume) of sulfur goes around the drip line, in a ring. Next comes mulch, over the sulfur, and some more water. That's it. It takes about a year for the pH to drop to 5.5 or 6, and two years for the pH to drop to 4.5. If the pH has risen above 5.5 in the third year, I will add some more sulfur, but I do not add any more sulfur if the pH is below 5.5.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"Some think the worst thing you can use is peat moss and pine bark"

Are you suggesting that the "Dirt Doctor" is correct, Drew? Or just drawing attention to a contrarian who fails to provide any references to bolster his proclamations?


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Eric, why didn't you incorporate the sulfur with the peat and soil? You figured the peat adequate? Guess it was. I don't think the sulfur placed below the plants roots could have accomplished anything for the blueberry, at least not for the first couple of years and maybe never.

All anyone needs to know is that it worked, I guess.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Re coir and CHCs: Some caution is advised. While there are many studies/tests that have positive results, there are many that have negative results and conclude phytotoxicity. My unprofessional conclusion is that the sourcing of the coconut is critical, and it is very possible to get bad materials. I feel that they can provides benefits over bark and peat, but they are not as reliably beneficial as bark and peat. Plus, their natural ph is significantly higher.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

How big of a planting hole do you typically dig, Eric? I'm curious about the total soil volume that's amended with peat. I have clay soil, as well, and, I've gotten in the habit of planting just about everything in raised beds/mounds. That works well for me, but I'm always interested to know about what works for others...


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"Are you suggesting that the "Dirt Doctor" is correct, Drew? Or just drawing attention to a contrarian who fails to provide any references to bolster his proclamations? "

To be fair he does go into why in other places on his web site. What he says has some merit. But I find the advantage out weigh any possible disadvantages. I will always use peat and pine bark. It's true pine does produce some chemicals that are counter to growth, but those are very water soluble and soon dissipate, something he fails to mention. Ironic as I heard that argument against pine hay, and although he prefers other mulches, says it's a good one. So I find his conclusions inconsistent. But he does have a radio show and has written a dozen books. Is considered an authority. So I would not just blow off his statements too quickly. I find the study of gardening a mixed bag, one man's meat is another's poison. I'm not sure what to believe except my own observations. And my observations find peat and pine bark to be extremely useful.
His main objection I think is that they offer little benefit in the form of nutrition for plants, are often used in dead soilless mixes, and he's a living, breathing kind of organic gardener. And he is right on about that. Although one can introduce bacteria and fungi to these mixes, and a little compost and they are very alive. In that respect I agree. I have seen the results of living mixes, and it is very impressive. Peat and pine can be part of those mixes, something he ignores. I also think he feels we should not be harvesting peat, and such. I'm not sure if we should or not? I have heard arguments both ways and have no idea whom is right? Now coir was thrown away, so now we found a use for it. I think that's great, but it cannot really replace peat in all situations. In some though it can and should be used. Hopefully it will be more available and cheaper down the road. I will always use peat for my blueberries, but I really don't have to use it for tomatoes, coir would work probably better. I bought some just to try and see. Tomatoes really don't like the low PH, so one must balance it out. With coir, it is closer to neutral so works well with say tomatoes or peppers, or at least should.
Plus it has the advantage of lasting longer, which should be accounted for when comparing price.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

I’m looking for anything to do besides work on my tax return, which I should be doing here at my computer . . . so I started reading up on bb’s and acidity. Why is low ph recommended/required? Do they really need low ph if the soil is fertile, as this thread initially asked?

A phd dissertation from 2003 has been interesting reading. See: IRON AND NITRATE ASSIMILATION IN BLUEBERRIES No, it's not a classical peer reviewed paper, but it is handy because of the way a dissertation more fully explains background and available peer-reviewed results.

Some takeaways to support hman’s observations:
The amount of, and type of iron available may influence the need for specific ph. Blueberries do not have the same capabilities as other plants to convert fe3+ into fe2+, which is the water soluble form that they can absorb. I infer that if fe2+ is available at a ph of 6.5, then perhaps bbs will do ok.

The type of nitrogen available also plays a critical role. Ammonium nitrogen uptake actually has a ph lowering effect on the surrounding soil, whereas other forms of nitrogen uptake can have an acidifying effect on soil. The type of nitrogen applied, or naturally available could impact whether a bb can tolerate a higher than “conventional wisdom” ph.

The variety of bb also plays a role, which is precisely what this dissertation is trying to investigate - "is it possible to breed bbs that can tolerate a wider range of soils" - as one TX native (not very tasteful) bb does.

However, the paper continues to support that a lower ph is preferential and produces greater health. And it isn’t just the cited early 20th century papers that support this. Late 20th century studies do as well. So, yes, bb’s do prefer a lower ph even if the soil is fertile. You could have extremely fertile at ph of 7, and the bb likely would become chlorotic because they are not adapted to be able to obtain necessary nutrients in those conditions, as some other plants are. Its just their nature.

Hman: have you ever considered sprinkling some sulfur on the ground around some bb’s up there? Say, 1/2 or 1/3 of them and see how they fare a year later compared to the status quo? Might be interesting.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"there are many that have negative results and conclude phytotoxicity."

It's from salt, Most coir companies already do this. But you can soak it for a day just in case.
I use COCOTEK and they are well aware of the problem, and the salt is removed beforehand.
I think it would be hard to find a bad product from any of the companies that make it. General Hydroponics makes COCOTEK . They have too many other product lines to chance selling bad product.

I looked at the reviews on amazon, 3 one star reviews. The problems were price too high, shipping too long, it didn't weigh out. Not one bad review about the product itself out of 58 reviews. Even the one star reviewers LIKED the product. I'm sold! It's the cheapest I could find too! Free shipping if you spend enough.

This post was edited by Drew51 on Sat, Feb 22, 14 at 16:18


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

It's from salt

To which salt do you refer? After all, many fertilizers are "salt" in the soil.

I am aware that some husks are processed in seawater. Soaking these for a day is not sufficient. Not without lowering the ph and using a buffer to release the tightly held ions. Others may come from trees that live off of seawater and the fibers naturally have a different ECa.

But it is not just seawater processing that can be an issue. Sorry, but I’m not inclined to look it up again at this moment, but there is also an issues with a high affinity for phosphorus or potassium, or something that alters the ECa. When the ph is lowered, as is appropriate for bb's, these (non-seawater) salts may be released and be detrimental to the plant. Overfertilization of particular elements, not an NaCl "salt" or any other chloride ion issue.

It still boils down to sourcing and reliability. There ARE bad coconut husk products out there. How is one to tell which is good and which is bad? How do we know the importer wasn't given crappy product on this latest shipment?

I've used CHC for more than a decade for animal uses. Just now starting to consider plant uses. Caution is definitely advisable as it can be detrimental.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

  • Posted by ericwi Dane County WI (My Page) on
    Sat, Feb 22, 14 at 16:34

I will answer the questions that were asked of me, above. The sulfur that goes into the bottom of the "V" shaped hole is not mixed in with the dirt because I want it to be assimilated slowly, over a period of years. The only purpose of this application of sulfur is to counteract the tendency of the surrounding alkaline soil to raise the pH of my blueberry shrub. I don't know how effective this method is, I have never tried to prove that it accomplishes what I expect. The typical hole dimensions are 24 inches diameter by 16 inches deep. The reason for putting down sulfur in a ring, on the surface, is essentially historical and idiosyncratic. When I started growing blueberries, back around 1993, I did not have a local source of sulfur, so I was using white vinegar, 5% acidity, mixed with our local tap water, to lower soil pH. This method works, but the vinegar disappears in about a month, so you have to keep repeating the application over the growing season. It is not a practical method for lowering soil pH. When I finally picked up a pH meter, and found a local source of agricultural sulfur in 50 lb bags, I had maybe 16 blueberry shrubs already well established, and I did not want to dig them up, apply sulfur, and replant. So, I applied sulfur to the surface, and that is how I have been doing it ever since.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

fwiw, here in west central Florida the commercial growers grow in pine bark only. They used to grow strictly in 25 gallon (half barrel) containers but are now trending to growing in swaths of pine bark on the ground. They don't add peat and don't even use pine fines. They just use the bark as it comes from the mills. It works for them.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

As a general rule no bark is good for growing plants/trees as it is hydrophobic. That doesn't mean that bark that resides with wood chips is detrimental--it isn't--but, a mix containing predominantly the waste bark from processed logs is plus when it breaks down its nutrients are no where near as good as wood chips. It is suitable for pathways however.

DirtDoctor is correct about the inhibitory phenols and turpines, but I don't think is it as bad as he states---but why add what may be problematic when you don't have to?

I can tell you that pine needles are not as acidifying as people (formerly me) say. Use powdered sulfur if you want to bring down pH. Even then getting it into and maintaining the pH5+/-0.5 range is iffy. And anyone claiming to grow blueberries (other than farkleberries) at a pH above 6 has my admiration and extreme doubts.

Blueberries seem to excel in a 33% mix of bark chips however. And I doubt pine bark would inhibit them. I suspect your non-acid soil will do that for you.

Here is a link that might be useful: bark raving mad


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

fwiw, here in west central Florida the commercial growers grow in pine bark only.

Which is interesting in light of the question starting this thread. Kind of the antithesis. The answer to 'can you grow bb in low ph mediums even if they are not fertile', is "yes" given what many commercial growers do.

The University of Georgia indicates that pine bark typically has a ph of 4.0 - 5.0. The linked page is an interesting read regarding growing them in pine bark (as well as details of the properties of pine bark).


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"To which salt do you refer? "

Does it matter? No, extraction procedures for salts work on all salts. If I were to soak it it would be in acid water, I never use tap for blueberries, and wouldn't soak in tap without sulfuric acid at least. Well I think I will just try it with tomatoes, and leave it out of any blueberry mixes. If the product performs, I may use it in the future. I guess why I think it is fine, is the product I'm using is made for pot growers, and they are a picky lot, and they love coir. Also one cannot ignore no complaints on any of the coir products, If you look at Amazon, many super bad reviews for products exist, well coir is one that has virtually no objections. As a matter of fact I highly doubt you can find one other product with anywhere near the positive reviews of coir. I never have seen one ever! Again I'm sold, if you're not cool, your choice.

This post was edited by Drew51 on Sat, Feb 22, 14 at 18:57


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

OK, after reading all of this, i think I'm just going to grow in pine bark and peat, we know it works. i'll save coir for tomatoes. Repot after a few years.

This post was edited by Drew51 on Sat, Feb 22, 14 at 18:44


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

"How is one to tell which is good and which is bad?"

Easy! Deal with a company that processes the coir.
CocoTek organic growing medium consists of three different types of compressed coco coir, it's not raw.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Charina, of course you don't need fertility in the "soil" as long as you supplement, as all those commercial growers do. Otherwise you couldn't grow plants in pots- most container planting mediums are not very fertile and require a steady supply of supplementary nutrients.


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RE: Do Blueberries Still Need Acidic Soil If Soil Fertile?

Just a little update: my bushes are finally budding after what has been the coldest and longest winter than my area has seen for many years. Once the soil warms up to 55 degrees and stays at or above that temperature for a few weeks, I'm going to get it tested again and I will also evaluate the health of my bushes. Photos will be forthcoming.


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