Coco tends to have a higher pH, potassium (I think), and actually has less "loft" than peat moss.
I would use peat moss or a peat-based potting soil for the peat fraction of my 5-1-1, rather than use Coco.

Referencing Al (Tapla) who has many times commented that commercial nurseries keep the amount of Coco
in their mixes to 10 percent or less.

Josh

I like using coir. It doesn't compact and is fairly neutral whereas peat is acidic. Make sure you get coir that has been rinsed because it usually does contain salt. Even when I buy pre-rinsed coir I rinse it a couple times before adding it to my potting mix. The amount I use depends on what I am planting and there's very few plants that I use a mix that is mostly coir fiber. I still use peat in many of my mixes but never the amount that the bagged mixes contain. No scientific basis I just use what works for me.

A copy/paste of something I wrote to compare

Peat vs. Coir

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 container media virtually eliminates lime or dolomitic lime as a possible 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 thoroughly, 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

Al you are extremely knowledgeable when it comes to plants and I do appreciate much of the info you post. Sorry it doesn't satisfy you that I don't know why certain methods work well for me but a question was asked and I responded. I'm not trying to persuade anyone to use anything in particular. I've used peat, coir and LF sphagnum for different plants.

Lol - I didn't even read your reply. My reply was to Lamora, and is just what I said it was - an exact copy/paste job of something I've posted a number of times when this topic arises, as it frequently does.

Al

Al~
That's great information you posted! I do recall seeing it in the past, but am always up for a refresher course, especially with being gone for awhile. I know awhile back Mike did a side by side test using this and about lost his tree's !
I can't remember if it was the chips or the coir.
The fact that it needs rinsed several times before using is a huge deterrent for me. Frugal with water here in Arizona. :-)

JoJo

I've been trying to help Margie as often as opportunity allows since she arrived at the forum, and I've been posting (copy/pasting from my word documents) that piece about peat/coir exactly as it appears above, since at least as early as '09. It directly answers Margie's question, so even if it was directed at someone in disagreement (which it isn't), there is absolutely nothing to be upset about. As I mentioned, I didn't even read Karen's reply.

Al

This post was edited by tapla on Sat, Dec 1, 12 at 21:13

I want to thank you all for the info.. very informative and I actually understood a lot of it~ weird for me~ lol.
Plus, now I know that Coir and Coconut Fiber is the same thing... missed that somewhere too..(slow learner here)

I wanted opinions and got a few, it helped me make an informed discion. (that does NOT look right-- sorry)

I'm sorry if this started an arguement, that was not my intention at all. Different Strokes for Different Folks~~ right?

Anyway, thank you all.
Marjie :)

Coir is definitely better as it is a by-product of coconut and therefore, renewable and low cost growing medium. It has a good content of potassium and phosphorous which is important for the growth of plants. Also, its pH is favorable for them. I think you'll surely get a good result using coir instead of peat moss.

Potassium content of coir so high it needs to be taken into account when deciding on an appropriate supplementation program if any significant amount of coir is used in a medium (say like > 15%). The pH of coir-based soils is so high it virtually eliminates the ability to use dolomite as a Ca/Mg source w/o addressing the outcome of high media pH. It's almost a certainty that w/o adopting corrective measures and taking coir's shortcomings into consideration that you would NOT get better results substituting coir for peat, Margie.

Al

This post was edited by tapla on Fri, Jul 5, 13 at 11:01