March 27, 2012
The Crisis Surrounding Peat
I was reading an article on Dave's Garden regarding a shortage of peat moss this year because of odd weather conditions in Canada, and this shortage will supposedly turn the gardening world upside down or something. Prices will soar, a 4" tomato plant will be $15, hipsters will battle octogenarians for the last zinnia on the table, growers might switch to other mediums, etc. Bedlam! And the author recommends that home gardeners stock up on their peat and store it for the long haul because, according to one expert, coir and compost are not substitutes because of issues with damping off and other stuff which were not fully explained but I assume exist.
I can understand the shortage and the demand vs. availability price increase, but there are a few points where I get confused with this whole thing...
I use a coir-based potting soil and vermicompost for starting vegetable seed. It doesn't seem to be a problem. I use coir-based potting soil and compost for potted plants. Again, not a problem. The plants that I buy and that grow well for me aren't in pretty mixes of perlite and peat. From what I can discern, I often see a good deal of bark mulch and other ingredients. This is especially true if I compare Lantana sold at a big box store (peat and perlite) to Lantana sold at a local nursery (bark mulch, compost, sand, etc.) - I have far better success with the Lantana sold at the small local nurseries who buy from local wholesalers, and I don't think it has to do with it being local (and, therefore, fresher) but rather with the potting medium and fertilizers used. The rougher and uglier the potting soil, the better the plant will perform in my garden. The only time I use peat and expect it as a potting medium is with carnivorous plants because those are the only plants that I grow that cannot have any nutrition what-so-ever and need an acidic soil. Coir, unfortunately, has some nutritional value, and it's PH neutral.
I have a lot of problems with the consumption of peat because there is a finite amount in the world (the life and death cycle of sphagnum is very, very long/slow) and bogs get destroyed to harvest it. I feel bad for using any at all. I avoid it as much as possible and wish all the plants I purchase were grown in a more sustainable potting mix. Of course, coir isn't all that sustainable considering it can't be locally harvested, but it's a waste product that can replace peat in many instances.
Compost is very local, and it makes some of the best potting mixes in my experience. Tropical Jatropha go bonkers in a potting mix in which compost is a major component. I mix it in rather heavily for many other plants including plumeria, and it's a commonly recommended in potting mix recipes.
And one nice thing about coir and compost is that they don't become as hydrophobic when completely dry as peat. Peat is a PAIN to get moist again if it dries out. The water just slicks off, and you have to either submerge the pot in a bucket of water or mist it for quite some time. I've had plants die in perfect little cubes of potting soil because of this particular problem with peat.
On a final note, one of the experts on peat in the article is associated with The Canadian Sphagnum Peat Moss Association. I would say bias is extremely likely.
So what's the deal? Why isn't coir and (heat treated) compost a good substitute for peat with the exception of growing carnivorous plants? Why should I buy an extra cubic yard of peat moss and store it in a shed I don't have? Why should any gardener do it? Am I missing something?
Let me know!