Sphagnum peat and coir have nearly identical water retention curves. They both retain about 90-95% of their volume in water at saturation and release it over approximately the same curve until they both lock water up so tightly it's unavailable for plant uptake at about 30-33% saturation. Coir actually has less loft than sphagnum peat, and therefore, less aeration. Because of this propensity, coir should be used in mixes at lower %s than peat. Because of the tendency to compact, in the greenhouse industry, coir is primarily used in containers in sub-irrigation (bottom-watering) situations. Many sources produce coir that is high in soluble salts, so this can also be an issue.
Using coir as the primary component of soils virtually eliminates lime or dolomitic lime as a Ca source because of coir's high pH (6+). Gypsum should be used as a Ca source, which eliminates coir's low S content. All coir products are very high in K, very low in Ca, and have a potentially high Mn content, which can interfere with the uptake of Fe.

I haven't tested coir, but I have done some testing of CHCs (coconut husk chips) with some loose controls in place. After very thoroughly leaching and rinsing the chips, I made a 5:1:1 soil of pine bark:peat:perlite (which I know to be very productive) and a 5:1:1 mix of CHCs:peat:perlite. I planted 6 cuttings of snapdragon and 6 cuttings of Coleus (each from the same plant to help reduce genetic influences) in containers (same size/shape) of the different soils. I added dolomitic lime to the bark soil and gypsum to the CHC soil. After the cuttings struck, I eliminated all but the three strongest in each of the 4 containers. I watered each container with a weak solution of MG 12-4-8 with STEM added at each watering, and watered on an 'as needed basis', not on a schedule. The only difference in the fertilizer regimen was the fact that I included a small amount of MgSO4 (Epsom salts) to provide MG (the dolomitic lime in the bark soil contained the MG, while the gypsum (CaSO4) in the CHC soil did not. This difference was necessary because or the high pH of CHCs and coir.) for the CHC soil.

The results were startling. In both cases, the cuttings grown in the CHC's exhibited only about 1/2 the biomass at summers end as the plants in the bark mix.

I just find it very difficult for a solid case to be made (besides "It works for me") for the use of coir or CHC's. They're more expensive and more difficult to use effectively. The fact that some believe peat is in short supply (no where near true, btw) is easily offset by the effect of the carbon footprint of coir in its trek to the US from Sri Lanka or other exotic locales.

That's the view from here. YMMV

Al

coco is the bomb. I love it nothing really can compete with it.

Here is a link that might be useful: coco

"Nothing really can compete with it"

How do you arrive at such a strong statement? It's pretty absolute, leaving no room for discussion, but "just sayin' it don't make it so!" Peat competes with coir MORE than favorably.

BTW - it's of no value to link to a site whose aim is to sell the product in question. I could easily go through the list of attributes and refute nearly every one of them, and those I can't refute I could render moot.

Examples: "Contains significant amounts of phosphorous (10-50ppm) and potassium (150-450 ppm)" ....... translates to - 'it is high in soluble salts'.

Coco has ideal pH in the range of 6-6.7 ...... First, the ideal pH range of container soils is lower than that, so it's already too high. Second, all plants need a source of Ca and Mg (dolomitic lime), but with a pH already too high, how can you add lime, which will further raise pH.

I could go on. Coir may be an acceptable 'You-can-make-it-work' substitute for peat, but it's definitely not an end-all panacea.

So tell me - how would you deal with the situation? Would you add lime and create a pH induced deficiency of Fe and Mn, or would you just SKIP the lime and let the plants suffer for lack of Ca and Mg? Inquiring minds would like to know? What's the plan? ;o)

Al

coco is the bomb. I love it nothing really can compete with it.

Kirk, I am going to be less direct than Al. You are being a douchebag.

Unless you are willing to offer something of substance please do not embarrass yourself making unsubstantiated, unsupported, absolutest claims.

It just makes you appear to be an idiot.

Al & justaguy2 Since the question posed deals with cost of peat would it be possible to blend some peat and coir together to reduce the cost of each container and thereby assist johnmich with a workable alternative to just using peat or just using coir. Lets forget about the flaming statement about coir(nothing can compete with it) sounds like something the cannabis club might say.

By blending you could lower the ph a little bit and provide the benefits of peat somewhat aiding aeration.

finding to cost ratio to benefit will be up to John to decide.

George

Wow! - hit a nerve there, JaG? ;o) Settle down - we don't want to lose you. You guys have a history or sompin? lolol

I'm with you though. I get soo tired of claims like "It works for me" - as if THAT was the end to all argument. ;o) I've even written a little piece about that particular phrase I'll prolly unload on you guys one day.

Of course you're right, George - your cooler head prevails. ;o) I do think I laid out a pretty good case in my first post - lots of considered info there. He (johnmich) can also see how to make coir work, if he wants or needs to, by either substituting gypsum for a liming agent, or like you said, mix in a little peat .....

Al

I've made mattresses from coir & they do start out with comfortable loft, but compact down surprisingly quickly - which suggests it's aeration properties in containers are not what you initially see.
I've collected coir & used it as a soil amendment for row crops. My tropical rainfall seasonally threatens top soil with erosion & the weathered coir shreds
allow an initial root network.
The % of amendments in outdoor ground cultivation is not only small, but over time diminished by wind/rain dispersing it. The relatively improved plant
growth is more a function of roots getting a chance than any lingering coir.
In container growing however, the coir % will be more likely to rise as the growing medium organic components break down & particulates leach away.
I find that when a little of a thing is good it does not follow that a lot of it is also good.

hope this helps

"The fibre itself, depending on the source and processing, ranges in pH from 5.2 Â 6.8"

"In general before using coir it would be beneficial to apply a calcium source: calcium nitrate (inorganic) soft rock phosphate (organic) and a mix of chelated micronutrients (inorganic) or kelp meal (organic)."

did i mention that you can keep reusing it. I have coco that I've been growing in for over 3 years.

somebody needs a chill pill:)

Here is a link that might be useful: coco

Let's see - you've quoted two commercials that show different pH ranges, the second being the more favorable - but the general consensus among knowledgeable growers is that if you're going to use coir, you'll need to work around the high pH factor.

From the second page you linked to: "Coir is by no means a perfect medium, in fact there are plenty of studies showing coir to be less effective than other soilless mediums ..."

Haven't you pretty much shot yourself in the foot when you consider you said "coco is the bomb. I love it nothing really can compete with it.

If you're feeling like making such definitive statements, of course you're going to be challenged. You really need to be able to support what you say with something better than links to commercials or seemingly favorable select snippets copied/pasted from sympathetic net sources - it's only fair.

What if I said unequivocally (I never would) that Superthrive was the best darned plant tonic on the face of the earth? - or Eleanor's the best fertilizer? People in the know would laugh me off the forum; and if I linked to their websites so all could read the wild claims as my proof ....... hooo boy! - they'd probably unite to ban my kids from the forum too - just in case there's a gene thing that mighta got passed down. ;o)

Take care.

Al

Arizona edu study on coco coir.

Here is a link that might be useful: arizona edu study

Kirk, you linked to a study which says:
With each irrigation, water soluble fertilizer was injected into the water. On bright sunny days, mature plants would be fertigated over 30 times per day.

Let's be real here. Fertigating 30 times per day = hydroponics and steps well outside what the normal container gardener is going to do. Even so there was no advantage over peat. If you live in an area where you can't get pine bark fines and peat is high priced then you make do with alternatives. That is just fine.

To say 'coir is the bomb and can't be beat' is just stupid and unsupportable.

whatever. I like to grow oraganic Hydro in Containers and when it comes to that style of gardening coco is pretty hard to to beat. I did go a little overboard saying it can't be beat but it is very easy to use and gets growth rates comparable to other forms of hydro.

i really liked this quote

From the second page you linked to: "Coir is by no means a perfect medium, in fact there are plenty of studies showing coir to be less effective than other soilless mediums ..."

the whole thing

Coir is by no means a perfect medium, in fact there are plenty of studies showing coir to be less effective than other soilless mediums. The trouble is that these studies test the fibre without giving it a charge of any nutrition. All of the studies in question also acknowledge that adjustments in nutrients and irrigation levels would make a difference.

very creative i like that.........

also the superthrive stuff your a very funny guy

Coco can keep up with DWC grown tomatoes and its alot easier, but to each his own

JaG!! What's gotten into you? I don't think I've ever seen you like this. I think you need a hug. I'm arranging for a polar beargram to be delivered (he'll be right at home anyway) - that's all there is too it. If that doesn't work, I guess I'll have to show up with one of those goofy hats and a red cape to distract you.

Hi, Kirk. About my leaving this part out: "The trouble is that these studies test the fibre without giving it a charge of any nutrition. All of the studies in question also acknowledge that adjustments in nutrients and irrigation levels would make a difference." Upthread, I said "Just sayin' it don't make it so." I think that kind of applies to these two statements. I cannot imagine anyone doing a grow test on a soil with a particular component (coir) w/o adding appropriate nutrients & then comparing it to a soil that contained proper nutrition. The second half of the statement (All of the studies in question also acknowledge that adjustments in nutrients and irrigation levels would make a difference). Leaves me to wonder WHAT studies were questioned, and WHO acknowledged the horrible disparity? Didn't happen - it's fluff. ... and the part that says "adjustments in nutrients and irrigation levels would make a difference." should have had a "DUH" alert posted in front of it. See why I didn't feel like I was deceiving anyone by leaving out "crucial testimony?

The real reason you're under so much pressure is simply because of the 'absolute' statement you made. When you make them, it makes people just want so badly to challenge them. ;o) You kept your cool under pressure, even if you still haven't proven a case (IMO). That part aside, it's much easier to live with "I did go a little overboard saying it can't be beat but it is very easy to use and gets growth rates comparable to other forms of hydro." than the original statement. That's cool - you should be able to express an opinion anytime you feel like it. It doesn't mean you won't hear alternate opinions, but at least you won't get pounced on. ;o)

BTW - I was never angry with you - just full of challenge & curiosity to see if you'd hang or give up & turn poopy. You did fine, as far as I'm concerned - I hope there's no hard feelings.

Take care. ;o)

Al

Well! er! excuse me! may I speak? Would someone give me a clue here? I have gathered so far that coir may not be a satisfactory substitute in SWCs for peat moss.
Would someone/anyone care to make comment (not in any absolute way, of course)on the merits/demerits of peat moss substitutes? Please?

There were two people who tried to protect you from getting a large load of bad information. In the post subsequent to the original, I went to considerable lengths to give you some hard science on the use of coco products. In the end, I see I'm being made sport of for the efforts. No problem. ;o) I hope someone comes along with the answer you'd like to hear and it all works out for you. My apology for the intrusion.

Good luck - take care.

Al

John,

The information which Al provided points to the major benefits of peat over Coir. Also the informtion on how to best use coir by adding Gypsum. I was hoping that a cost benefit could be reached since you had indicated that peat was more expensive than coir, by blending the two (peat and coir) to bring the total cost of each container down. I had hoped some input from either Al or Jag however why not take 1/3 peat 2/3 coir with additional gypsum to your mix instead of all peat or all coir. This would be with the additional items in Al mix.

The coir apparently compress and looses some of its aeration ability that peat provides in the mix. By blending the two together I was looking for some cost savings instead of just using peat which would be the better choice over just coir.

Maybe Jag or Al would comment on this suggesting as my reading your request focused on what solution would work and a lower cost if possible. Hopefully I didn't read it incorrectly.

George

Not to negate anything stated previously (and certainly not the science quoted by Al and others), but coir is commonly used in potting soils in areas where peat is scarce or expensive or no longer approved for horticultural purposes (i.e., the UK). While it may not be interchangeable with peat, it is a viable substitute as long as you consider what it may lack or additional problems it may pose and address them accordingly.

The following is an excerpt from an ATTRA publication regarding approved organic materials for potting soils. While the 'organic' issue may not necessarily be germane, the info is helpful.
Coir
Coir dust, a mixture of short and powder fibers, is a by-product of the coconut fiber industry. Most coir comes from India, Sri Lanka, the Philippines, Indonesia, and Central America.(16) It looks like sphagnum peat but is more granular and does not contain twigs or sticks.(17) Coir has a pH of 5.5 to 6.8 and usually contains higher levels of potassium, sodium, and chlorine than peat.(18) Coir lasts two to four times longer than peat, but it is more expensive, mainly because of shipping costs.(18) Coir is typically shipped in compressed bricks, which expand when wetted. It is easier to wet than peat because there is no waxy cutin to repel water.(17) It also has a greater water-holding capacity than peat.

In a study performed in the mid-1990s at Iowa State University, researchers found that petunias and marigolds planted in a mix of 80% coir and 20% perlite grew both taller and heavier.(19)

One distributor recommends a mix of three parts coir to one part compost.(8) Another offers a product that contains 35 to 45% coir blended with peat moss, vermiculite, and pine bark.(18)

There are a few cautions when using coir. Supplemental fertilization with potassium may need to be cut back and nitrogen increased. There is also the possibility of salt damage.(20) Salt water is customarily used in the processing of some coir fiber and it is important to purchase only low-salt coir products. It is also wise to ask whether any prohibited wetting agents or binders have been added to any commercial product.

For the tone of my comments above I do apologize. Clearly I was in a foul mood and took it out on those undeserving.

In response to acceptable peat moss alternatives I would say pine bark fines. More stable and better aeration.

Al (Tapla) doesn't do SWC, but I do. Even in SWC I don't use more than 25% peat total in the mix. My current mix for SWC is 2 parts bark, 1 part Turface MVP and 1 part peat. I don't think Al goes over 10% peat for any of his applications and some of his are peat free.

When using bark that is partially composted instead of fresh one could probably omit the peat altogether in SWC.

In my view coir is s step back from peat and peat is something I have moved away from for the most part. Where I live coir is also exponentially more expensive than peat. I do understand that there are places coir is less expensive and it is an attractive option.

I rather doubt that there is much difference between coir and peat if we assume the potting mix only contains a small amount of either, but if either is to form the basis of the mix then one needs to know how to use it in terms of watering and fertilizing. I can't help here as I have no hands on experience with coir and given the insane prices being asked for this industry waste product in my area can't see myself ever getting any.

Sorry to resurrect this old post but I wanted to because it has A1's analysis of using Coir. I live in the Philippines where Coir is so cheap it's almost free and in many cases is free. Pine bark and Peat are not available to me. Gotta make do so it will be really cheap. Hoping the SWC concept will take off as water isn't exactly free, either.

Materials available to me:

Coir is super-abundant but will require soaking to remove excess sea salt. I just contacted a domestic Perlite manufacturer and am hoping for a good price on that. Coarse sand is not a problem but does require screening to remove fine particles. Chemical fertilizer can be found but not cheaply relative to other ingredients.

My goal is to make a mix that's something like:

5 parts Coir
2 parts Perlite
2 parts Coarse Sand
1 parts Compost

And then use the fertilizer strip method suggested by EB.

My idea is to add sulfer to my compost to keep the resulting PH of the mix a little lower, but being totally clueless I really need help.

Cities in Philippines have high population density and most families are lucky to grow even a flower or two. I'd love to make SWC gardening work here, if possible.

Any comment welcome!

Some thoughts:
If you have the ability to screen the sand in volume to come up with a particulate size that suites the climate, I think you can make things work nicely. As I see it, the sand should probably be a larger presence in the soil if weight constraints aren't an issue.

I'm thinking you're probably going to find your answer closer to:
3 parts coarse sand (size tbd)
2 parts perlite
2 parts coir
1 part compost

I think you will need to use a synthetic fertilizer. Soil pH likely WILL be an issue on the high side, so you'll need to address that before you can fine-tune anything. Elemental/agricultural sulfur probably isn't the answer. I'm thinking you'll probably not be able to use dolomitic lime because of the pH issue (CaSO4 + MgSO4 instead).

Al

Thanks, A1. I really appreciate you posting on the forum. I'm the guy looking up element symbols from the chart but I'm trying to be a fast learner.

I'm saving eggshells and beef/pork/chicken/fish bones in case those meals could help me. And I'm ready to begin my journey with alkaline-loving vegetables like cukes and cabbage just so I can make a fair start. Trying to buy time while I find a locally-sourced inexpensive way to deal with Coir. Gypsum does not jump out at me from its availability perspective... but neither did Perlite at first. I'm looking.

It's a challenge but I'm learning.

As a teen I grew plants in greenhouses in VT from Jan until May for $3/hr. The job I really loved was driving the electric cart loaded with flats, lol.

I'll keep you updated. Should have my soil test kits, soon.

Thanks, again.

Oooops. A little more info.

The idea of the SWC is more due to the fact that many Filipinos haul water. By hand in buckets or on hand-trucks because they don't have access to a city water supply. As meticulous bathers they're used to carrying water... but for plants.... I dunno. If SWCs are not the answer then I think I can introduce rain water collection, especially where I live, now, with its heavy rainfall.

Labor here is cheap and sometimes free or for lunch. Screening sand works. What gets screened is really soft and fine. I give it away to carpenters who want it for cement projects. The rest I'm saving.

Adding sulfer to my compost was to hopefully allow time for it to break down into sulferic acid. And hopefully to also benefit from the organisms already present in the compost.

I have access to the manure of roughly 30 chickens. Depending on reproduction and when we eat them. LOL.

That's my little world.