The lone voice of horticultural reason

Rice Hull Compost

Ran into this stuff for the first time this season at Tonkadale Greenhouse in Minnetonka (boy, has that place turned into a great garden center) and was intrigued enough to ask a few questions. Here’s the story:

Lou Gerten over at Gerten’s Greenhouse in Inver Grove Heights is always looking for the perfect potting soil concoction. They make their own at Gerten’s, as do many good growers, and Lou heard about composted rice hulls. They are lightweight and keep soil from compacting, so it remains fluffy and friable, making for good root development and air circulation in the root zone.

Turns out there was a source in New Orleans, and when shipped in bulk up the Mississippi river on barges it became quite affordable. So Gerten’s started bringing it up the river and experimenting with it.

Experiments were so successful they now sell it in bulk form at Gerten’s. If you are making new garden beds or in any way amending soil, composted rice hulls dug or rototilled into your soil beats the pants off peat moss. A lot of gardeners don’t realize how quickly peat moss wimps out and compacts to the point where it really isn’t doing anything to keep your soil friable. The benefits diminish pretty quickly after one full season, I’ve found.

Rice hulls, on the other hand, take a long time to break down, lasting three to five years. In a pail they look and feel a lot like coffee grounds, but work up a handful, squeeze it, and you realize how brittle and almost sharp they are.

Rice hulls have neutral pH and no nutrient value. They do not retain moisture. The whole point of using them is to keep your soil structure light and friable so plants perform at their best. The folks at Tonkadale tell me it is the absolute best relief they’ve found for clay soil. Obviously, rice hulls work fine in tandem with peat moss, and/or compost from your bin.

Over at Tonkadale they bag it up and sell it to the public (pictured), while at Gertens you can buy it in bulk and tote it home in your pickup (or, they’ll deliver; the minimum delivery amount is half a yard, which, as all good Renegade Gardeners know, is nothin’).

Don Engebretson
The Renegade Gardener