Use Leaves; Don’t Lose Them

Black Walnut in a bank parking lot.  A good street tree, apart from its nuts, but they are better than plums.

The Grants Pass City Council has finally decided to get out of the cheap compost and wood waste disposal business and save about $200,000 a year.  Our sewage solids will be trucked to Dry Creek Landfill to become methane and make electricity.  The Jo Gro property will be leased to Republic Waste Services, where they will continue under that name, accepting wood waste and yard waste and making compost with the latter, but it will be without bio-solids or city subsidy, at prices Republic chooses.  This means that the City will also not be picking up bagged leaves for free this year.  It is unlikely that Republic will either, since they have to compete with Southern Oregon Compost, which certainly doesn’t pick stuff up for free.

Since the City will not be picking up leaves for free, this gardener will be not be either, but I will pick up loads for $1 per bag, 40 lbs or less, to use on my customers’ properties for weed control.  But I’d really rather that you use them on your own property to keep the weeds down.

Leaves make superior mulch for weed control because the top layers dry out quickly, and do not make a good seed bed until they become compost or worm castings.  Worms love leaves for food, and they and the soil are sheltered by them from freezing, drying, wind, and rain.  Two inches can stop most small plants and small seeds.  More can stop bigger plants and seeds.  But bulbs and established perennials will generally work their way through several inches of leaves. 

A foot of leaves will decompose more quickly when covered with an inch of compost, and allow vegetable seeds that are sprinkled or poked into the compost to grow into huge plants.

There are no leaves in this area that are not good for mulch.  The ones that people question, oak, pine and black walnut, are the best for weed control. 

Oak and pine are said to be too acid, but they are not acid themselves; they just take a full year to decompose.  Shade and summer watering cause acid soil by leaching away calcium; evaporation brings calcium back to the surface.  These leaves shade the soil longer than most other leaves.  But when they are piled deep, the worms eat them and sweeten the soil with their castings, resulting in good soil.

Walnut leaves, especially black walnut, are said to be herbicidal and kill plants.  But they are actually a pre-emergent herbicide that stops any seed smaller than a nut from coming up.  Starts and established plants are not affected.  Black walnut leaves are quickly eaten by worms and are generally gone by the end of spring, except for their long petioles.  But their pre-emergent effect sticks around all season.  To sprout seeds on black walnut soil, lay down an inch of compost and sprinkle them on.   To sprout larger seeds, spread another inch of compost on top of them.

9/20/2013  Published in News-You-Can-Use-by-Rycke.blogspot.com, and GardenGrantsPass.blogspot.com.

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Rycke Brown, Natural Gardener        541-955-9040      rycke@gardener.com

Gardening is easy, if you do it naturally.