How do commercial composts compare to those made at home? Are all commercial brands the same, and how do I tell if it is a quality compost?
Ken Vold, Ramsey, MN
Peter Wright, animal waste specialist at the
Cornell University Cooperative Extension Service
in Ithaca, New York, replies: Commercially made compost is essentially produced like homemade, just on a larger scale. Because it is manufactured mechanically, commercial compost is turned more often and reaches temperatures high enough to kill off weed seeds and bacteria. This results in a well-made, homogenous product. But that’s not to say industrious gardeners can’t produce high-quality compost at home. Both products perform well, so choosing whether to buy or make compost is really a personal preference.
One advantage of commercial compost is convenience. It’s ready to use right out of the bag. But, not all products are the same. The ingredients used—such as agricultural crop residue, food waste, industrial sewage sludge, animal manure—may vary from brand to brand and from year to year.
Homemade compost also has its pros and cons. An advantage is that home composters control what gets added to their piles, but the time and labor involved may require more effort than the average gardener wants to devote to it.
With commercial compost, look for a product that is uniformly dark brown to black, with a mild, earthy smell, and uniform texture. There should be no lumps or clods of undecayed material. Composts containing sand or gravel should be avoided. Also watch out for compost with an unusually high moisture content—a sign it was poorly made. Try lifting a few bags and avoid the heaviest ones.