@Embothrium So bark soil might be an ideal medium for Christmas Cactus, simulating in some way its natural growing environment in crevices of bark on trees?

"Unfortunately, that claim is one I've had to field many times before, along with hydrangea, which don't like it either."

Might want to reconsider that notion! Hydrangea macrophylla flower coloring depends on available soil aluminum. It - not just acidic soil - is what makes the blue flowers blue (sufficiently acidic soils allow for Al mobility - insufficiently acidic soils tie up or immobilize aluminum). In fact, aluminum sulfate is also known as "hydrangea blueing" (and sometimes labeled as such) and is routinely applied to hydrangeas to encourage the development of very blue flowers.

Many plants can be very sensitive to Al levels in the soil, so it should not be applied willy-nilly and is a poor choice for soil acidification as a result. But the only issues hydrangeas have with Al is the lack of it.

Westes, exactly.

Morpheus, I'll share pictures of the bark I use tomorrow. It's the same bark I use to make my 511 mix. Fine grade orchid bark.

"@morpheuspa Can we call "a pinch" 1/4 tsp dissolved into three gallons of water?

At that concentration, approximately how many ppm of iron is in that water? I guess I should factor in that the water will already have DynaGro 9-3-6 with iron at 0.1%"

That's just fine. Let's see. I'll give you all the math so you can reproduce it yourself in the future if you want, but the final total just from the ferrous sulfate is 71 PPM elemental iron.

That's the solution PPM, not the soil PPM. Soil weight minus what the plant uptakes, minus what doesn't bind and simply turns to (effectively inert, at least for a while) rust and other iron compounds, minus what washes out, will be what soil binds. I very much doubt it'll be more than 20 PPM of the 71, it just doesn't work that way.

Ferrous sulfate heptahydrate, all told, weighs about 18 grams per tsp (looked that one up).

So 1/4 tsp ferrous sulfate = 4 grams, approximately.

3 gallons of water = 11,340 grams at around 70 degrees and sea level pressure (by definition as 1 gal water = 3.78 kg = 3780 g).

4/11340 = 3.527^10-4

3.527^10-4 = 352 PPM ferrous sulfate in water, from the ferrous sulfate alone (definition; 10^-4 translates to hundreds-place in PPM).

Ferrous sulfate is 20% iron by weight (we've been ignoring the water binding throughout and I'm content doing that knowing we're shooting low throughout).

352 * 0.20 = 71 PPM elemental iron (rounding up)

71 PPM Iron

I'm not sure how much DynaGro you'll be adding, so I can't calculate that.

@morpheuspa the "maintenance" dose (i.e., intended for continuous application) of DynaGro is around 1/4 tsp per gallon, and that is how I mix it. Of course I am mixing about 70 gallons in a rain barrel, all at once, and then I use that up over a week. I hope the minerals stay evenly distributed throughout the container.

It sounds like I might also be fine mixing in iron sulfate at 1/8 tsp per gallon, just to add additional margin of safety.

"Might want to reconsider that notion! Hydrangea macrophylla flower coloring depends on available soil aluminum. It - not just acidic soil - is what makes the blue flowers blue (sufficiently acidic soils allow for Al mobility - insufficiently acidic soils tie up or immobilize aluminum). In fact, aluminum sulfate is also known as "hydrangea blueing" (and sometimes labeled as such) and is routinely applied to hydrangeas to encourage the development of very blue flowers.

Many plants can be very sensitive to Al levels in the soil, so it should not be applied willy-nilly and is a poor choice for soil acidification as a result. But the only issues hydrangeas have with Al is the lack of it."

Yes, you were the one who said this the first time, too. If you would be so kind to begin here and do the research further:

https://homeguides.sfgate.com/aluminum-sulfate-hydrangea-care-68920.html

Aluminum is toxic to hydrangea just like any other plant; they have no special immunity to it and tales that they do are not to be "reconsidered" and are not "notions." Use iron rather than aluminum to acidify the soil rather than send (already adequate in any soil) aluminum levels even higher.

My very close to neutral base soil has Al levels of close to 500 PPM, entirely high enough to color a hydrangea if the soil is acidic enough. Which it is, as my half-blue, half-pink hydrangea will attest every summer.

ETA: Actually, if you would continue the claim that aluminum is "lacking" in any soil, please supply the research. I have never seen a soil test with low enough aluminum to be a problem, including the sandiest possible soils. /ETA

You can also use sulfur if you can dig it in, but of course, don't surface apply. Nobody will thank you for increasing sulfur dioxide levels in the atmosphere. And of course, sulfur works quite slowly, so the course of years may be required. Iron sulfate works quite quickly.

Aluminum sulfate is a bad and very dangerous garden myth that needs to die, die, die. Please remove it from your lexicon--as we have discussed before, and I am hopeful you will synthesize this time.

"@morpheuspa the "maintenance" dose (i.e., intended for continuous application) of DynaGro is around 1/4 tsp per gallon, and that is how I mix it. Of course I am mixing about 70 gallons in a rain barrel, all at once, and then I use that up over a week. I hope the minerals stay evenly distributed throughout the container."

They don't, but close enough, and hopefully Brownian motion keeps things agitated enough. :-)

One thing to consider is oxidation of things that can oxidize and loss of some things over time. By the end of the week, don't count on any iron in the mix, it oxidized. You'll get it back eventually, but not for some months and bacterial action. And so on with other things. NPK isn't much impacted (although N could be an issue as part of this is ammonium...).

Let's just assume the quarter tsp has the same weight as FeSO4 (it does not, it's far lighter), with an 0.1% iron weight elemental as stated (which I can believe).

As such, 4 grams becomes 0.04 grams of iron added to the above. If we pretend it's ferrous sulfate, it would be 0.20 grams (it would need five times the mass if it were, since we're playing chemistry games here).

Consequently, instead of 4 grams of ferrous sulfate, we're adding 4.2 grams. This is exactly a five percent increase, so the math is trivial. The DynaGro is adding 3.5 PPM of iron (kind of zip, really...) to the 70.4 PPM from the first set of equations. The grand total is now 73.9 PPM.

Let's call the new total 74 PPM elemental iron equivalent in the water (and of course, it's supplying some sulfur as well).

@morpheuspa Okay, that sounds like a good experiment. I will take two sets of matching container plantings - with two different rhodie varieties - and one of each pair will get added iron once a month. Should be interesting.

Do you have any opinion on brand names for the generic chemical in this list?

https://www.amazon.com/s?k=ferrous+sulfate+heptahydrate

@User

well, I just lost a large post...bummer. Houzz strikes again.

Anyhow, here's the bark I've been using: Micro Bark, which is the same Douglas "Fir" bark as E.B. Stone's other Orchid Bark products, just in different packaging, different volume, and at a lower price.

Also, this is the perlite that I'm using. The last two years I was using a larger grade, but it displaced a lot more moisture and led to a very fast-draining / drying mix, so I opted for this perfect stuff this season.

Hi Josh. You guys on the west coast are lucky that you can get fir bark easily. How much for 1 or 2 cu ft bag? Porbably does not even need sifting by the looks of it. Pumice is also difficult to get here and expensive. A 2 gallon bagged pumice can easily be $20+. Yourr perlite looks good too. Perlite is reasonably priced although we do lose quite bit sifting to take out dust which can be quite a bit.

I feel very lucky, indeed!

This perlite is right about 3/8 of an inch, almost zero dust at all. Really good, clean stuff.

These days, I only sift or rinse the bark if I'm making a more refined mix, for orchids or succulents or smaller pottings for example. For the 511, I just dump the bark into a wheel barrow and pick out any apparent pieces of interior sapwood. The Micro Bark is $11 for 2 cu ft, whereas the other "Orchid bark" is $8 for 1 cu ft....so the choice is clear. I've found, and used, other barks when I can find them in the right size; but, although they are less expensive, the quality and consistency is nowhere near the same as the Greenall Micro Bark.

Here's an orchid mix I put together the other day: bark, perlite, lava rock, and a scant amount of Turface that happened to be in the bottom of the pond-basket I mix in.

I think my Perlite's even finer, although the bark seems about the same (or finer, again). Here on the east coast, we seem to get pine bark (which I object to for environmental reasons; we tend to displace other forests to plant pine).

Your mix looks great!

This thread is not about aluminum sulfate and I do not intend to engage in a long, distracting and unnecessary dissertation about its pros and cons. Suffice it to say that I was by no means the "first" to have remarked on the relationship between Hydrangea macrophylla and aluminum! It was discovered almost 1OO years ago and is thoroughly documented in horticultural and scientific literature. Applications of aluminum sulfate are routinely used in the production of florist hydrangeas for the retail market and it is also advised by hydrangea specialty nurseries.

Any number of plants have a resistance to aluminum toxicity....hydrangeas are just one. Scientific papers - like this one - have established that available aluminum is not necessarily uniformly toxic and is actually beneficial for the growth and cellular development of a variety of acid loving plants (but not all). It has also been determined that Al in soils also helps to access, or conversely, neutralize certain other plant nutrients. It is also important to note that aluminum is present in soils in at least 4 forms, only one of which is readily available and creates toxicity issues and then only in highly acidic (<5.0) soils. The less acidic the soil, the less toxicity is present or likely for any plant type.

So yes, in not very acidic soils (>6.0), soil aluminum is not readily available regardless of the measured levels and applications of aluminum sulfate may very well be required to develop that very desirable, uniquely blue flower color. btw, a hydrangea that blooms with both pink and blue flowers is growing in soil that is not adequately acidic to free up the aluminum required to produce blue flowers.

I'd also question just exactly what that link was intended to point out in defense of the "myth" that aluminum sulfate is SO BAD!! Of course it can be over-supplied - any nutrient addition can, with corresponding detrimental effects - but it is a non-issue for bigleaf hydrangeas if applied according to label directions and avoiding applications close to to known Al sensitive plants!

It might also be important to note that SFGate is not considered a reputable horticultural or scientific resource. It is an adjunct online publication of the San Francisco Chronical, a newspaper, and is just a selection of cut and paste articles gathered from who knows where and without scientific substantiation.

Looks like my thread on nutrient testing of bark has become yet another thread on the gritty mix. :) Okay, I will post a photo of my mix too, just to be social. I am using pumice in place of granite, and I understand the pros and cons of each and I do not think it is a big deal to substitute the pumice.

Ain't nuthin' wrong with that. It has a great CEC, so pumice stores resources like nobody's business. It's a consideration on discard, again, and for application of resources (compared to granite's near-zero CEC), but that's about the only major difference I'd care to discuss at all.

Do you plan to reuse mixes? I've discussed that but...I never do. I always feel the risk of transmitting a disease, or carrying a badly balanced set of resources from plant to plant, to be far too high. When it's time for a change, out it goes into the garden to be scattered for sunlight and air to take care of.

@morpheuspa I always re-use soil mixes. I spend a fortune on creating this stuff (the labor costs more than the material) and waste not want not.

And, morpheuspa, there is no way to "dig in" the sulphur applications recommended to grow weed free, organic blueberries in Maine. Iron sulfate isn't used because it's expensive and it can result in salt stress.

Of course, I'm thinking you could pre-prep the area before planting the blueberry. But surface-applied sulfur will result in sulfur dioxide (a pollutant and another greenhouse gas) entering the atmosphere, and a reduction in the effectiveness of the sulfur applied.

Fortunately, if you can so much as scratch it in a bit, that will at least help.

If the argument is to use aluminum sulfate, then it also shouldn't be used because it can cause salt stress (because it's a salt), and it's more expensive than sulfur.

"Iron sulfate isn't used because it's expensive and it can result in salt stress."

Don't apply it at a rate that will cause salt stress, firstly. That's a bit of a nitpick because you also wouldn't apply nitrogen at that rate--many forms of which are also an acidifier.

And yes, it's a bit more expensive (I found 8 pounds for $9 for sulfur versus 8 pounds for $12 for iron). Iron is comparable with aluminum sulfate...

Aluminum is a toxic element. Stop adding it to soils where it's always adequate. I'll pay a few extra dollars not to add to the potential toxicity of the soil should somebody make a mistake in the future and send the pH too low.

For that matter, don't apply sulfur at a rate that will overshoot your pH, cause root stress, etc.

I just read a very interesting soil test, with a pH of nearly 9. Nine. Naturally; the highest I've ever seen. Aluminum was one of the lowest I've ever seen naturally at around 150 PPM. That will still be entirely sufficient for a blue color on a hydrangea...but you'll never get the soil pH low enough to show blue no matter what you did. Sulfur wouldn't react well in that soil and has so much soil-stored Ca that you'd need massive amounts. Forget anything else. You live with bright pink.

I should have explained. I'm talking about low-bush blueberry fields in Maine, which aren't planted. They're cultivated. I have about 15 acres of blueberries, which were only certified organic eight years ago. In those eight years, I split the profits with someone who helped me change the field management. This will be my first year doing it alone, so I hope to school myself enough to pay the field's bills---without spending a bunch of my time on it.

Instead of talking over-applications why not discuss proper application? "They" say that the amount of Iron sulfate needed to adequately lower the pH on blueberry fields is tricky because that same amount neeced---not an over-application---can cause salt stress.

I've read that proper application of Aluminum sulfate might be exactly what my field needs for weed control, but It's not allowed under organic certification. I'm not sure how I'm supposed to apply the sulphur if it's needed. We used to spread the glyphosate by airplane, I don't remember seeing any spreaders in my field, but that must be how the sulphur is done.

I can't speak to organic specs or ag management, I don't do it. However, I always speak to overapplication and misapplication because it's really easy to do. And lacking home testing--which is expensive and unreliable, and almost always done completely wrong--it's impossible for the home user to know if they're doing it right. So I'll always go with the least-toxic answer (iron itself can be toxic too, but at about 10,000 PPM at a pH of 5, less somewhat lower, but it's more likely to simply block other resources).

Ag's less likely to use a method that's even $0.50 per acre more expensive than another, of course, even if it's superior. Or if it takes longer, or has to be minded a bit.

As a homeowner, I don't care. I'm willing to adjust things so the left of the hydrangea is pale pink, the right is pale blue. It's a fun challenge and the time involved doesn't matter.

"I don't remember seeing any spreaders in my field, but that must be how the sulphur is done."

Usually. It's the wrong way to do it due to the sulfur dioxide problem, but agricultural practices aren't known for their efficiency or planet friendliness, usually. At the very least, a slitter should be used, and the sulfur dropped into that, so at least some is protected against atmospheric exposure.

As to whether that would be an issue for blueberry roots, I can't say; I don't raise them.

But again, see that $0.50 per acre expense. Although in this case, losses of up to a third to the atmosphere should be considered in the sense that it's a complete waste.

@annpat Aluminum is extremely toxic to human beings. Why would you even consider adding it to the soil of a food crop? Playing color tricks with flowers is one thing. Adding that to any soil that is going to be used to grow human food would be deeply irresponsible IMHO, and it would certainly violate the rules for an organic crop.

Are you saying you are allowed to use glyphosate for weed control on an organic field? That's deeply concerning as well.

Well, you're going to be horrified, then, to learn how many commercial blueberry growers use Aluminum Sulfate. In addition to acidifying the soil, it's an effective method of weed control, which is why it might also get recommended.

I didn't say that I use Aluminum Sulfate. I said that if my field needed acidification, it might well be recommended in a non-organic program. I found this in extension service literature, which might explain an additional reason it's used: "Blueberries, unlike most plants, tend to take N up in the ammonium (NH4+) rather than nitrate (NO3-) form, so growers tend to use such N sources as ammonium sulfate."

My blueberry field was managed by a commercial outfit until I was able to convince my partner brother and the blueberry company to allow us to go organic. After two years of allowing organic growers, the hassle managing organic berries and commercial berries separately in one facility became too much for them and they dumped all their organic growers. I found another purchaser and we've been "organic" technically for 12 years and certified for 8.

While blueberry growers no longer use arsenic on their fields, they continue to use glyphosate. If you ever get to see miles and miles of a gorgeous, flawless blue carpet of berries in the summer in DownEast Maine or a brilliant carpet of red, orange and purple foliage in the fall, you're seeing a glyphosate managed field. If you come upon a field constantly waging and losing battle with goldenrod, Black-eyed Susans and milkweed, you're passing my field.

My organic blueberry manager who got us the certification dumped us last year when he went under, and in January, my 72-year-old brother became one of the 727 Mainers to die of CoViD to date, and I just learned this week that he left me his half of the field. I don't have a very clear plan on how to proceed. If a soil test indicates a need for acidification, I know that the organic recommendation will be for an application (not an over-application) of sulphur.

The reason they don't use Iron sulfate, morpheuspa, is not so much the cost, but the salinity. In order to reduce the pH using the amount of iron sulfate recommended, iron sulfate can cause salt stress in blueberry fields. I don't know why proper application would cause a problem, but "they" say it can. That's all I can tell you.

If you read Garden Gal's post above, she can explain it better than I have. I'll say this, though, it's hard to have a discussion with people who only want to discuss over-applications of a supplement. Including the article that Morph linked. Its objection to the use of aluminum sulfate is regarding over-application.

I once drank five gallons of water in a day, and my foot turned black. Don't do that either.

annpat: Nothing much to say but enjoyed your write-up and providing a perspective on blueberry cultivation at commercial levels.

That's nice. Thank you.

And now a reasonable response to the attempted deflection.

We should have discarded blueberries as an edge case in the first place, and a required technical overapplication as compared to hydrangea to begin with--with a pH span of 4.3 to 5.5 absolutely required.

So as far as application amounts apply,

As noted, aluminum is going to be available at the lower end of that range, and if available, also potentially leaching into the water table. So that's not really that good.

Historically, I had thought they used sulfur for that. Not an optimal thing, but I'd rather sulfur dioxide be released into the atmosphere than aluminum into the soil and water. At least it's less damaging.

https://www.epa.gov/wqc/aquatic-life-criteria-aluminum

Acres of leachate into a stream or river or pond...yeah, that's fun. You can follow the research as linked from here.

And use on weeds is simply irresponsible. I've heard of other concoctions equally as bad, so at least I can't say it takes the cake.

So while we can throw out blueberries as an edge case, requiring massive acidification and overapplication compared to the plant we were discussing, I think I may be removing them from my diet just for not being planet-friendly in any sense, even the "organic" ones that use aluminum. I'll have to see what the non-organic use. If they actually use sulfur, that's really a better "chemical" in question. And glyphosate on weeds does not bother me; far less than yet more aluminum added to the soil and water.

I certainly hope you aren't reporting posts that aren't in accordance with yours. I have never seen anyone bullying you---merely disagreeing with you--which you somehow take as a personal affront.

My field is MOFGA certified and we adhere strictly to the standards. My certified organic blueberries are sold commercially to mostly Japanese buyers. I've co-owned the field since 1976 and I mentioned that my brother and I only switched to organic management 12 years ago. Prior to that, we managed our field just exactly the way every other commercial blueberry farmer in Maine does---using glysophate, burning the fields every other year, mowing, using some chemical---Velpar?---that kills the blueberry moth, etc. You don't need to school me on glyphosate, which we haven't used since 2009.

I have been an "organic" hobby/food gardener since I first began serious gardening in 1974. The blueberry field was not managed organically only because my partner/brother and Merrill's Blueberry, were opposed. When I finally persuaded my brother to switch, the blueberry factory was also game. They changed their mind after two years and we had to find someone else to buy our berries.

Japanese buyers value organic blueberries more than U.Sians do. I agree that shipping food, unfortunately, expends a lot of fossil fuel. which needs immediate addressing. In the meantime, in addition to not approving of Japanese people having access to healthy food because of transportation, do you likewise feel that Mainers should be deprived of oranges and avocados and pineapples for the same reason? Conscientious people shop as locally as possible, but most are unable to do it exclusively.

I've never heard of any organic program using aluminum as an herbicide, so I can't discuss that.

Regarding tattling to the administrators, no you're wrong. Never in a million years would I "agree" that some silly little dispute here on this forum "deserves reporting" to admins.

No, I never said it was used as an herbicide. I said it is beneficial in weed management. I gather it makes the soil inhospitable to plants that are not blueberries. Never did I say that it was an herbicide and never did I say that I, myself, have used it for any purpose. I don't know if we have or not. I merely pointed out that it is a widely used practice among commercial blueberry growers, so there are experts who recommend its use.

"What it does show is the limit of organic commitment people have--convenience, or their wallet. In your particular case, your wallet. That's fine, and it's not a problem. You'll go so far, but won't go far enough to take a smaller profit on your crop. No big deal, but acknowledge that without being confrontational about it."

You know absolutely nothing about me, and your speculations about me are incorrect and insulting. I assure you; no one is more of a spendthrift and a wastrel than I am.

@annpat Sorry to hear about your brother. I lost my beloved aunt to Covid recently. It has been a real scourge.

westes, thank you. I'm sorry for your loss, too. My nephew and niece have a beloved aunt, and they would miss her terribly, so I understand. Never did I expect a year ago that our family would be touched by this; I'm sure you're as shocked as my family is. My brother contracted it, was hospitalized, and died by himself two weeks later.

I am sorry for your loss as well, annpat.....and you too, westes. They say that one in every three Americans knows someone who has died from Covid, so I guess I should just thank my lucky stars that I am not included in that unfortunate group. The area where I live has only been lightly touched and fatalities are rare but they do happen. Will be so relieved once we finally get past this.

annpat and westes very sorry for your loss of beloved ones. It has been a terrible year for so many people. It is sad. I do not know anyone directly who died of covid. Apparently half a million health care workers died in the last year worldwide due to it. Take care all of you.

My state has "only" had 728 deaths, and other than my family, I don't know anyone who's gotten it.. My brother was two weeks away from vaccine eligibility, so it's been hard on his children and widow and sister. I am due for my second Moderna vaccine next Tues., but I don't anticipate giving up my masks anytime soon.

@annpat In general, how much do organic blueberries sell for by the pound, from the farmer to the wholesale buyer? How does that compare against the local retail rate at an organic grocery? I might have an idea for you on that since you lost your US-based wholesaler customer.

@morpheuspa I think most of what drives the organic food movement is pure selfishness by people wanting to minimize the amount of industrial poison they ingest into their own bodies. In that framework, they are okay with consuming twice as much fuel to ship the organic blueberries from Chile to Canada because that is "someone else's problem" and does not directly affect their body.

That said, there are some of us who care about overall environmental impact as well. Maybe on organic foods, there should be a labeling requirement that would score how energy inefficient a given food is based on where it came from and where it is going. Some people might alter consuming habits based on that information.

If you are an artist, I would love to see some of your paintings.

@annpat Regarding acidifying your soil two ideas:

1) Maybe start using peat moss as a top dressing mulch on the soil, in combination with compost if you still want some nutrition in the mulch. Peat moss is incredibly acidic so that will help to flavor any rainwater or irrigation applied from the top.

2) Investigate the possibility of using an auger to drill holes parallel to the roots that you could fill with some combination of peat and sulfur. The peat would further acidify the mix and would hold onto water which then starts to liquefy the sulfur. That method would fix morpheuspa's objection about the sulfur released into the atmosphere.

Obviously getting the quantities of everything right would require a professional to be involved and some experimenting with plants you are willing to lose before you roll out to the whole field. Questions you need to answer by research or experiment:

How many holes around the roots?

How far away from the plant center?

How deep are the holes?

What combination of peat and sulfur in the holes?

I am betting someone in the scientific literature has already done a similar kind of experiment and it could be used to help inform your own experiments.

annpat: Thanks again for your perspective on blue berry cultivation. I always wondered about cultivation at scale and what it involves and especially organic cultivation. I have talked to a few local organic vegetable producers (CSA's) and as I understand the margin is not huge as people think it is. They train and pay their workers better. But they save on packaging and distribution. They really cannot compete with big companies but they survive on reputation and quality and a captive customer base.

Sadly, starting this year looks like no more CSA produce for us after 25 years being dependent on them. The owner of our CSA farm retired end of last year and put up his farm for sale but no buyers yet. Partially due to Covid.

The complexities of the global food chain is quite something. Local produce here is limited to Summer mainly and winter it drops considerably. Most of the food even if it is just produce is shipped from somewhere else and has to go through various energy consuming steps.

Looks like this thread got cleaned up well by the management.

@tropicofcancer (6b SW-PA), agreed!

Josh

For no particular reason, I deleted a long post.. Tropic, my field was fallow last year, but a lot of fields in Maine went unharvested because of restricted travel due to CoViD. Migrant workers do most of the harvesting, although my field was harvested by two people walking with an hand held harvester in 2019. Two other rakers did the rocky areas. That group were all train riders and they were bound for Washington state to harvest something else next. Maybe grapes (but that seems too early). Ironically, I was bound for Washington myself (by plane) with four quarts of fresh blueberries in my carry-on that I hand-picked while talking to them.

westes, because our low bush blueberries spread by rhizome, they don't like soil disruption so plugging the soil isn't an option, I'm sure. The mulch idea isn't far-fetched, though, I've just learned, if applied now for weed suppression, but I don't think peat will be sufficient to drop my pH to the desired 3.9 or 4.

They recommend a wood bark mulch (for weed suppression, not pH reduction), but also mentioned peat. Peat to cover 15 acres would be a substantial cost for a field that already barely pays its own way. My field is supposed to pay the taxes on the other 50 wooded acres in the parcel. Addressing concerns about carbon footprints, peat moss, of course, is imported and shipped from Canada. I do have access to almost unlimited wood chips, and I have a weedy field because I haven't figured out the organic management practices yet. Besides achieving a pH of 4, I'm supposed to mow three times during the non-crop year using more fossil fuels to negate my organic status. For an optimum crop, I hope to be able to burn the field, but I don't know how to go about that since the only organic method is with straw as fuel and I don't want to burn down my whole camp road. I'd give it a go, but a half-hearted burning is actually counter productive; you need a hot burn to be of any use, and I think I'd lose control of a hot burn. My plan is to try to find another organic manager. I'm at a point where the field needs some immediate attention before I lose the weed battle.

By the way, I don't know that I even need a sulphur application. I may have had one in the last eight years. As soon as the field is thawed, I'm going to have a pH test done. I know for an absolute certainty that if my soil needs acidification, sulphur will be recommended by MOFGA to be spread on a dry day.

The post I deleted explained that the whole point of the field is to pay the taxes on 50 adjoining acres that abut a camp road. My brother and I are constantly approached by cottage owners who want to purchase a "square" of that road land "just to put a garage on". My brother, who owned other land, constantly came to me after some person or another approached him with an offer and I repeatedly told him that my interest in the land---the only land I own---is in keeping it undeveloped. The property has dozens of vernal pools and lots of standing dead trees and I want to keep it as an untouched woodland habitat. I just learned that my brother left me his portion of the land, which really makes me want to get that field in good shape before I lose it to wildflowers.

@annpat What exact varieties of blueberries do you grow?

What kind of soil do you have, and what is the pH previously tested at?

Regarding plugging: are you sure that a few vertical drill holes on the perimeter of the plant count as "soil disruption"? I don't think that would physically impact more than 2% of the root system of the plant.

Do your 50 wooded acres have any way to pay by harvesting a renewable forest on it? That's enough acreage that you could cycle through the whole thing every 10 years. If you want to preserve it as woodland, maybe you could get the state or regional government to buy it and convert it into a hiking area?

Morph? Never have I ever gotten into a conversation with anyone ever about urea. I don't ever remember having any conversation with you, frankly, so I don't know what your issue is. You have made it sound like you and I had a dust-up about urea. I'd point out that Maine is the largest producer of wild blueberries in the world and we aren't new to the crop. At this time, I'm going to stick with the known and proven conventions. We're not so hickey that we don't have our own talented soil scientists.

I just lost a whole long post... I have several varieties of vaccinium in the field, westes, but the primary berry, the one we encourage, is angustifolium. I'm going to keep editing in case I lose the post.

Here's my field. From the east, it looks like a Santa boot with a rock wall resembling a fur cuff.

It's a dead end private road and I wouldn't encourage any more traffic than I already get with blueberry thieves sneaking in---mostly my neighbors and their children.

Here's another picture of a local field in the fall, not mine. See how pretty it is? Glyphosate.

My brother and I butted heads about the woods. He wanted the fir and pines gone and hardwoods encouraged, which I was prepared to do, except I didn't want skidders on the land.

@morpheuspa Maybe we could confirm the dispersion rates of sulfur horizontally before we discard the idea. Note that doing it my way avoids the environmental concern because you can just plug the hole with soil. Also, I was proposing to put peat moss into that hole, which should further allow pH change through the soil. Quantifying both the sulfur and peat moss efficacy in that configuration is the hard part, but maybe there is research.

@annpat Create a folder on your computer for Gardenweb posts. Rather than author the post on Gardenweb, author it in a Notepad file in that folder with the date and appropriate name on the file. When you have it done then copy and paste the whole thing to Gardenweb. That gives you a more reliable backup on your computer hard drive.

What is the pH of your soil? Is that a stable number over time and multiple tests?

What I can find is mostly for toxic soils, where sulfur is not dispersing at appreciable rates horizontally. However, it's being measured with other contaminants, and that's going to cloud the picture a bit. Many of those will soil bind.

annpat: Can I say OMG? What a piece of land you have. I can see why someone wants to buy a piece here and there. Everyone wants a piece of paradise.

Mentally I got stuck when you said you have access to wood chips. I dabble in growing mushrooms in my backyard and woodchips are great for certain kinds. Like wine cap mushrooms I grow in my super tiny woodchip bed. I have to pay for my woodchips but the result is quite astonishing. Hardwood logs/chips/ are perfect for shitakes and many other gourmet mushrooms. Oyster mushrooms are the easiest. Mushrooms can fetch a premium but I am guessing commercially doing it will be not that straightforward.

Conifers like pine, fir are not much suitable for mushrooms. Even heartwood resists decay and generally hostile to most of the edible mushrooms. Maple and oak are versatile and very mushroom friendly.

At this time, I'm going to stick with the known and proven conventions. We're not so hickey that we don't have our own talented soil scientists.

Well said and that is the best route. Speculating and experimenting based on opinions of backyard gardeners like me is not a good idea for a for a farm like yours. You may gather some new knowledge here and there but that is about it.

"Looks like this thread got cleaned up well by the management."

I wiped some things because why bother with some around here;
half of the posting are examples of moving the goalposts. After due
thought, why take the bait?

That is a very curious and interesting statement. So many ways to parse it. Thanks for sharing.

So Morph deleted all his rude posts and left a few neutral ones. Is that his usual method of operation? What a waste of time!!

Despite the claims made in that little blip quoted by ToC above, I doubt he - morpheus - was the one doing the 'wiping' or had them removed :-) After the warning posted by Houzz management on another contentious thread last week, I believe he pushed it too far yet again, his offensive and insulting posts were removed for cause and his account has now been deleted. At least his profile page has been removed.

Waste of time indeed!

Okay. I might have to delete mine now. I'm left looking like I'm talking to myself.

Yes, a lot of dangling comments are left behind. I have these in several posts and I have a half mind to leave them as they are. Will look like I am talking to a wall.

Also remember that it is quite easy to just create another account with a different email address. And I would not count out that he will not be back.

But let us at least enjoy this moment of peace.