I'm not sure how warm it will get; the mat's not the one I used last year. Hmm, maybe that one's down in the (still dark) basement?
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CowPots™ are made of composted dairy cow manure, after most energy has been converted to methane gas (used to power dairy operations) and the liquids returned to crop fields. It's a sterile, quickly biodegradable, mildly nutrient rich medium for a pot - how cool is that?
I'm SO tired of nursery pots made of non-recyclable PP plastic. Sure, I can reuse them to some degree, but what about all the pots that are thrown away? CowPots™ are similar to peat pots, but decompose more readily apparently, so will be perfect for vegetables. Longer-lasting coir- and paper-based pots may be an alternative for plastic for containerized plants, too.
Black nursery pots, made of HDPE plastic, are recyclable, of course, along with plastic milk jugs, shampoo and vitamin containers, and a variety of other products.