It depends on how much of what is in it. You can probably do w/o the vermiculite though.

Al

Yea, the limestone ain't really necessary either. Other than that, sounds like you have a good list of basic ingredients for a container mix.

The (dolomitic) limestone provides both Ca and Mg, which isn't found in a VERY high % of soluble fertilizers, and you can't depend on the other soil components to provide them. A very good argument could be made that it IS necessary if you're to have plants that grow normally.

Al

True...true...others user Ca & Mg supplements, as necessary though (Epsom Salts, for one). It's not always the best approach to load up your soil mix with minerals in preparation for possibly needing them. I prefer to add nutrients as necessary, depending upon current potting mix, but I guess that's just a matter of opinion.

Very few use Ca and Mg supplements. The vast majority use lime. A few use CaSO4 or MgSO4 in special cases when pH is an issue or for other reasons. We're all welcome to an opinion, but I don't think I can agree with what you said. Generally, container soils benefit from the addition of lime to bring the pH to a more favorable level than peat or bark soils usually come in at, pre-limed. In addition to raising pH, lime also has the fortunate attribute of being able to supply Ca and Mg in a favorable ratio. It's difficult to imagine how you could improve on that.

ANYtime you fertilize, you're loading up your soil with the salts that plants use as their building blocks. Best growth can be achieved when the nutrients are present in soils continually, somewhere between adequate and luxury levels and in a favorable ratio to each other.

Trying to add nutrients as needed is a guessing game with the plants vitality in the balance. If you wait for symptoms to appear, there are already deficiencies and growth has, and will, continue to suffer until they are corrected. How else will you know when to add the 'needed' nutrient? Intuition? If you are that intuitive and add the nutrients BEFORE symptoms appear, you're "loading up the soil" with nutrients just like everyone else on the forum.

BTW - we do understand the concept of fertilizing frequently with dilute solutions.

Al

Al: I completely agree with you. Lime is great & has its uses. I personally like to use it to pre-treat soil before planting in it, though I haven't done so in a few years. Adding nutrients as symptoms appear may have not been the best wording for me to use regarding my current method. I use a nicely balacned potting mix & then, on a regular schedule throughout the life of the plant will fertilize with whatever standard "food" i'm using for that specific plant that year. Regarding the Epsom salts & other additives I don't consider to be needed year round, I also add them on a schedule, but only do so for partial life of the plant (usually from bud formation on to life-end for pepper plants, for example). I think you have a great method & potting mixture. I just don't think it fits my needs & I have my own merthod that has always worked just fine. This merely states that, as we all know, there are several different methods of gardening techniques( potting mixes, fertilizing, etc.) that work just fine. It's really a matter of opinion & personal choice.

I continue to get "signs" that my methods are working well for me...

{{gwi:32141}}

I'm glad you agree. It's just that when someone speaks in absolute terms w/o any qualification, like "Yea, the limestone ain't really necessary either." I feel like there SHOULD be some qualification by someone. Since limestone is pretty much accepted across the board as the very best way to raise pH while supplying necessary Ca and Mg in peat/bark soils, I think that from the perspective of practical applications, we're probably much closer to "Lime is necessary in container soils." than we are to "Lime is unnecessary in container soils."

I'm not confused and have no problem separating 'easy and practical' from 'I can make it work another way', but I wanted to be sure others had the information necessary to do the same. While I agree that it's all a matter of personal choice, I think there is actually very little opinion in what I've said so far, and lots of fact that can be easily supported by science and sound husbandry.

Al

Yea, well most people on here (including myself) tend to originally state opinion as fact. This being an online chat forum, 90% of posts will likely be so. That is merely what I did when I stated, "Yea, the limestone ain't really necessary either."

Then, of course, when it contradicts opinions of others, the discussion begins. =) This would be the point at which, if I knew little to nothing about said subject, I would consult something like This Wikipedia Link which specifically mentions container gardening. I would read on & still be persuaded against using it for the multiple occurrences of the phrase "laboratory synthesis" in the article. A lot of gardeners prefer natural methods of producing & growing their vegetables, when at all possible. I'm one of them. Hence, my choice to not use laboratory synthesized lime.

The following excerpt from the Wikipedia article doesn't help the cause of lime either..."In nutrition, dolomite is sold sometimes as a dietary supplement on the assumption that it should make a good simultaneous source of the two important elemental nutrients calcium and magnesium. However, laboratory experiments conducted at the University of Alberta demonstrate that dolomite is practically insoluble in stomach acid and is eliminated from the body before significant magnesium or calcium can be absorbed. Dolomites from Mississippi Valley-Type ore regions such as the Old Lead Belt and New Lead Belt in southeastern Missouri United States often include significant levels of lead and other toxic elements."

Anything you put in your soil becomes a part of what grows in that soil.

We both know nowadays that there are a plethora of resources available (some just to those with ample funds to purchase them...the EarthTainers frequently mentioned on here, for example) for boosting any & all aspects of plant growth. Most of them are worked up in some type of laboratory. Some people will use as many as they can get their hands on. Some will not. I should have no need to go on because you should realize that, no matter how much you like to think it's fact, the use of lime in container soils is & will always remain a matter of opinion.

Peace - Steve

I said that I stated facts about the use of dolomitic lime, and for the record, there isn't one that you refuted. I didn't say there are not courses alternative to the use of lime, only that what I stated was fact. See quotes below.

The article you linked to mentions the two words 'container gardening' as an application for the use of dolomitic lime, which doesn't support your position at all, and it goes into NO detail whatsoever. So it's sort of a smokescreen. If we're going to focus on container soils, we probably shouldn't be expanding the conversation to include dietary supplements that have no bearing on the subject; after all, we don't water with stomach acid. ;o) All soils, ores, and other things taken from the earth's crust contain lead, arsenic, and other myriad contaminants. That some forms of limestone mined from an area known to be rich in lead should contain some lead is not much of a surprise. It's normal for mineral products to be contaminated with elements and compounds other than what they're mined for. It's highly doubtful that limestone from those areas are packaged for garden/lawn use. No one I've ever met has used "laboratory-synthesized" garden lime, either.

"I should have no need to go on because you should realize that, no matter how much you like to think it's fact, the use of lime in container soils is & will always remain a matter of opinion."

What I said was, "... limestone is pretty much accepted across the board as the very best way to raise pH while supplying necessary Ca and Mg in peat/bark soils". I also said "... container soils benefit from the addition of lime to bring the pH to a more favorable level than peat or bark soils usually come in at - pre-limed. In addition to raising pH, lime also has the fortunate attribute of being able to supply Ca and Mg in a favorable ratio. It's difficult to imagine how you could improve on that."

I'm not sure what there is to argue with in those comments, the crux of my posts. It's all true, but there is room for you to expand if you like - if you have a definitive way to improve on the use of lime to raise pH and supply Ca/Mg in peat/bark-based container soils - please share.

Al

So we're clear, I defined the crux of what I presented. These are facts (following), not opinions, and another repeat of what I put forth from the onset of the discussion. If there is argument, it should be against what I set forth, not (and I'm not using this term in a derogatory sense) against straw man arguments you create to knock down.

1) "...limestone is pretty much accepted across the board as the very best way to raise pH while supplying necessary Ca and Mg in peat/bark soils.

2) ... container soils benefit from the addition of lime to bring the pH to a more favorable level than peat or bark soils usually come in at - pre-limed.

3) In addition to raising pH, lime also has the fortunate attribute of being able to supply Ca and Mg in a favorable ratio."

These statements are so widely accepted as fact that there should be no need for me to establish any form of proof. If I say water is wet, there is no burden of proof on me. If you have a dispute with these verbatim quotes, I think you bear the onus of disproving them.

The invitation to reveal a/your superior strategy still stands.

Take care.

Al

BTW - My apologies to you, Fred - for getting off track on your dime. ;o)

Here's a good thread that expands on the (non)use of vermiculite in container soils...

Here is a link that might be useful: tapla and vermiculite

"And now back to our regularly scheduled program..."

Al asked for the percentages of each many posts ago. All I have found is that the processed pine bark is 60%. The product is Fafard's 52 Mix. From Fafard's web site, it looks like their heaviest. I bought two bags and did use it for a few toms and peppers. I added a little lime and I marked the pots with "52" so I'll be able to see if the toms are any different than those that are in Berger's BM6. Thank you for your comments.

Fred, I am glad you came back. By the time I read all this the whole thread had gone to 'heck'.

I knew that mix was Fafard 52.

It is 60% pine bark
24% peat
8% perlite
8% vermiculite

That mix looks good to me--I just bought a bag myself.:)

Al's large batch mix figures out to a 3-1-1 (not 5-1-1)
pine bark , peat, and perlite if you use the 2 cubic feet 'recipe'. No vermiculite.

In the Fafard mix the vermiculite will help with water and nutrient retention. Also looks like it may work for a SWC. Fafard says it is a coarse mix with
Excellent drainage and good air space.

If anybody finds Fafard's Nursery Mix that contains 75% bark and 25% peat --Fafard says it is coarse and well drained. Just add some perlite if you like.

Steve...I'm reading this thread, trying to get a better understanding of the subject, and I just can't help point out that Wikipedia is not the holy grail of information that you imply...especially in this case.

For instance, the last paragraph of the article you referenced, subtitled "Uses", regarding the U of A lab experiments and the Mississippi valley ore deposits, clearly shows "citation needed". So, all your posturing about needing proof only shows you to be a hypocrite, considering Wikipedia's open nature that allows opinions not yet cited as fact to be posted (hence "citation needed").

And by the way, you have contributed nothing to my understanding...but thanks for posting just the same.

Here a case study done on the use of dolomitic limestone at Penn State University with scientific facts.

Quote from it: "Soil test recommendations for magnesium are given in
several ways. The recommendation is sometimes given as the
amount of magnesium to apply, or the recommendation may
be given as a minimum magnesium content in the recommended
limestone. Recommendations on Penn State soil tests
are given in both of these ways. Sometimes the recommendation
is simply: "Use a dolomitic limestone." This is less
desirable because there is no set definition or minimum
magnesium content for a limestone to be labeled as dolomitic.
If the soil is optimum or high in magnesium, either a calcitic
or dolomitic limestone can be used. The decision should be
based on the availability and the cost of limestone."

PDF Here

That better, Mr. Nohandle (curious nickname...)? =)

No, actually, it's not better.
I don't see what your point is anymore.
Your original statement that sparked this off-topic "debate" (really you just flying off the handle) was your assertion that limestone isn't necessary. But, if anything, the article you are now citing seems to contradict your position, while adding some clarity to the composition of dolomitic limestone, which was never in question.
Typically, most sane people try to design their statements to fit the subject, and not the other way around.

Peace out