Those who watch the show know I use a lot of coconut coir. You see, I hate peat moss, I HATE IT. Hate those stupid peat pots, hate the little Jiffy pellet things. Peat moss has two settings: too wet and too dry. It grows algae, it attracts fungus gnats. I hate it. So I use coconut coir despite the fact that the entire history of horticulture seems to be based on peat moss. Peat moss may in fact be better for plants, but I hate it. HATE IT!
So I use coconut coir. It is the waste product from coconut’s outer husk. The shell you see in the grocery store has had this outer husk stripped off, and the large and fibrous husks are used for doormats, upholstery, mattresses etc. The “fines” used to be considered trash, and places like Sri Lanka literally had mountains of the stuff laying around. Someone had the bright idea to use it as a peat substitute, and my life got a little brighter, because I HATE peat moss. Now, the fibers used to be soaked in brackish lagoons, so there were some early problems with salinity, but if you get a good horticultural grade it should be leached out and there won’t be any problems with this. I’ll also be showing you a little trick which might help with this, just in case. Coir holds just the right amount of moisture, and when it does dry out, it remains hydrophilic (receptive to water). It is less dusty than peat, seems to hold more air, smells good, and doesn’t break down as fast. Finally, it is a good use of a “waste” product.
So for those of you who are unfamiliar with this material, here’s a little how to:
The coir usually comes dried and compressed into bricks. You can get sizes ranging from a builder’s brick on up. The one shown is the equivalent of the small bricks and is a quarter of a large pack.
If you have one of the small bricks, just throw it into the bottom of a five gallon bucket. If you need to break one up, go in along the side, and pry it apart as shown.
Here you can kind of see the fibrous nature of the stuff. One brick takes one gallon of water to rehydrate.
I have been adding gypsum to the water before adding it to the coir. Use warm water, and add about a tablespoon of pearled gypsum. Shake it up. The pearls won’t completely dissolve and that’s fine. The water will look a little muddy as shown. This helps with any residual salinity, adds calcium and sulfur, and helps with any potassium imbalance that can occur when using coir.
Addendum: I noticed a possible magnesium deficiency in my pepper starts when using a 1:1:1 ratio of coir, vermiculite and perlite. Obviously, this seed starting mix doesn’t really contain any nutrients, and is only for the first few weeks of growth. However, even when the plants started getting a weak fertilizer solution, they showed interveinal chlorosis which seemed to clear up after a dose of epsom salts (magnesium sulfate). I’ve started to experiment with putting a tablespoon of the epsom salts in the gallon of water along with the gypsum slurry. I’ll give an update on any results as soon as they are known.
Addendum: Again with the peppers, again with the chlorosis. I think it had as much to do with irregular watering (too dry, then too wet) as with any deficiency. Still, letting them dry out, then giving epsom salts seemed to perk them up, and once I potted them up, they really took off. I’ve been putting the epsom salts in the soak water for a couple years now, and again the results are inconclusive, but it certainly isn’t harming anything at this concentration.
Add the water, just dump it all in. Notice how dark the coir is where the water has hit it. You can really tell moisture levels in coir by the shade. Dark equals wet, light equals dry.
This is after a couple minutes. You can see how there is a little bit of light shaded coir that still isn’t hydrated. You can start breaking up chunks and mix the wetter with the drier here.
The easy way to get it consistent is to flip it into another bucket. Do this a couple times, allowing fifteen minutes for each flip.
Fluff it all up and break up any final chunks. You can see it really expands in volume. Then I usually do the bucket flip thing once a day until it is half way dry again. Much easier to work with then and it won’t get that mildew smell.
One thing I’ve noticed is that a lot of the longer “mattress fibers” are getting into the coir these days. This isn’t a problem when you planting up bigger plants, but they can be a pain when you are doing a seed flat. I’ve been sifting them out as shown below.
I used an old onion bag. Pack the coir in loose and shake the hell out of it. The “fines” end up in the bucket, the fibers stay in the mesh bag.
Here’s about a year’s worth of sifted fibers. As I said, I only sift out the long fibers when I’m planting seed flats, so not too much of a burden.
That’s it kids. Give this stuff a try, especially if you HATE peat moss. (I hate it!)