black gold

Like many locations in the San Juans, the top of Obstruction Island was shaved by an ancient glacier.  Topsoil is almost non-existent.  In 1993 my husband, Jeffrey, built our first compost bin out of pressure treated wood and we started composting our leaves and kitchen scraps to make dirt for our garden.  It wasn’t long before we purchased 500 red worms from a mail-order seed catalogue and they, or their children, are still out there at work.

Our new deluxe compost bin

By last summer the woodbin was starting to fall apart.  One of the problems that had plagued us with this bin was that the roots of near-by firs kept finding ways to creep in, — no matter how we lined the bottom.  If you can’t locate your bin well away from trees, you may want to first pour a concrete pad.  Ours has a slab with drainage and two bins, exteriors of 4×4 by 32” high.  Three sides are mortared cinderblock. The fourth has u-shaped guides attached to the cinderblocks, — slots for 3 2×10 pressure-treated boards. Across the top of the worm’s bin is a large metal fire screen that first keeps the raccoons out and then becomes the sifting screen.  The two bins are 3 ½ feet apart, slightly wider than a wheelbarrow.

Once you have your bin, fill it with leaves and your garden and kitchen scraps, avoiding any diseased plants, meats, and citrus.  Add the red worms.  Be sure to keep it moist over the summer.  Each time I bring out the food scraps I add about a gallon of water.  And each time I cover the compost with more leaves from the large pile of maple leaves we raked up in the fall.  The next time I am back with more kitchen scraps, the leaves have dropped down about a foot.

Worm Highway: By the end of summer it is time to move the worms.  The other bin has been filled with leaves that have settled some. Take all the fluffy organic matter off the top of the current worm bin and move it to their new home.  I remove two of the boards from the old one and pile organic matter up to the lip of the bottom board, also propping that board so there is exit out the bottom. This organic matter crosses to the new worm bin.  Then I wet the undigested leaves and cover the whole thing with a tarp, rocks on the sides – again to keep the raccoons away from my worms.

If you don’t have a second bin, simply add more organic matter to your tarped (top and bottom) worms and close off while you sift your dirt.  Then put the whole wad of quasi-dirt, organic matter and worms back into the bin after it is emptied (see below).

The worms are left for several weeks to exit their bin and cross their highway to the 2ndbin.  The Labor Day forecast for rain called me to action this year.  Last year when the rains came early I found the sifting was miserable work.

The hope is that all of the worms have exited the dirt in the first bin and followed the call of the organic matter to the new worm bin.  I was very pleased to fine black dirt with few worms across most of the “highway.”  The dirt bin was virtually free of them.


Sifting: You need a wheelbarrow, the spark screen and containers.  I have saved gallon milk bottles  and I cut down the front quarter to make an open jug.  I can get 11 of these in our wheelbarrow.  When I am potting plants, planting bulbs in the fall or starts of new plants in the spring I just take several jugs from their shelf on the back of the shed to where I am working.

Shovel the dirt onto the fire screen and scrape it back and forth eliminating the rocks, sticks and fir cones.  The beautiful black soil falls through into the milk jugs.  What misses the jugs is scooped into 5-gallon buckets.  In only about three hours I had sifted out 20 gallons (4 buckets full) of sticks and stones, leaving over 100 gallons of black gold soil.

this year’s harvest

By the time I finished on Saturday afternoon, soft showers had started. The pile of leaves gathered last fall from the near-by six huge maples was almost gone.   Then worms were at home in their new bin piled up with fresh leaves while the first of this fall’s leaves started drifting down.

the two bins, our house and raking up the last of last year’s leaves.

Here come the new leaves! Another year of black gold in the making.

©2009 Caroline Buchanan

A somewhat different version was first published on September 15, 2009 in Project Home, a division of Sound Publishing, Inc. and circulated with The Islands’ Sounder, The Islands Weekly, and The Journal of the San Juans.