Sow there! – Gypsum and leaf mold in the garden, Oct. 28, 2016

October 28, 2016

About this time of year the battle with the fall leaves begins. The muted colors are beautiful while dangling in the branches of trees. Next, leaves become a sticky, slippery nuisance on the sidewalks, hood of our cars and on top of our favorite plants.

Chico residents can rake the leaves into neat piles near the street and eventually they will be picked up.

However, a portion of that tree litter can be used in your yard. Last year we swept a big pile to the edge of the cyclone fence.

The fact that the pile sat there for a year has more to do with oversight than good soil intentions. The result was a weed-smothering mulch mat, and eventually some good leaf mold.

A Monterey Bay Master Gardener article, makes a good case for adding leaves to the compost pile. Ideally, the gardener would rake the leaves into small rows, then run over them with the lawn mower. If the mower has a catch bag, you can easily dump the leaf confetti into the compost pile.

Most people don’t keep their compost pile hot enough to cook weed seeds, so try to keep weeds out of your leaf mounds.

Great garden gift

Thank you, thank you to my friend John who dumped the ginormous California Master Gardener Handbook ” on my chair at work a few weeks ago. I haven’t had this much fun reading since “Taylor’s Weekend Garden Guides,: Soil and Composting.”

When it comes to allowing leaves to decompose, the garden book recommends adding nitrogen, which could mean steer manure or synthetic nitrogen. This replaces nitrogen that is lost when leaves decompose.

What to do with clay soil

For many years, Bob Scoville has been my Glenn County go-to guy for plant information. I gave him a jingle this week to talk about leaves. As is sometimes the case, we ended up talking about other things.

On Bob’s side of the river, much of the soil is heavy with clay. You may notice your soil is heavy clay if you use garden soil in pots. When the plant dies and the soil dries, the dirt looks like a giant hockey puck. I think this is actually how curling was invented.

People with heavy clay soil might dig a hole and fill it with water. It could be hours before the water drains.

Bob’s solution on the west side of the river has been to add bags and bags of gypsum. We’ve talked about this before, but perhaps not in as great of detail. Gypsum is material you find in sheetrock, which makes up the walls in your house.

Bob buys gypsum for about $6 for a 50-pound bag at Northern Star Mills in Chico. “I just bought eight more bags last week,” Bob bragged.

The material looks like white flour and in the winter he sprinkles it on soil beyond the canopy line of his fruit trees. That’s where the roots reach. A good ratio is one pound per 10 square feet, he noted.

Bob gets very excited when he talks about is Alberta peaches. Apparently they should be entered into the world fair, and he’s intent on producing another mouth-watering crop next year. Having great soil is important.

I envision him working late at night, humming incoherently, wearing a white 19th Century bed cap – as each fist filled with gypsum is unleashed into the air, the sky is filled with a white mist.

When he’s not sprinkling, Bob also mixes gypsum with compost to work into the soil.

Why gypsum works

Good soil has four requirements, Bob explained – minerals, organic matter, water and air. Gypsum helps loosen the soil and minerals are made more accessible to plants. After five or six years, and many years of gypsum, Bob said his heavy clay soil has improved.

Leaf mold

Leaf mold sounds like something yucky you would scrape away with a spackling knife. However, leaf mold is basically a pile of leaves that you have allowed to sit in pile for a long, long time. See my example above.

This brief and informative article from Tulare/Kings counties Master Gardeners, k notes that leaf mold “mixed in with your garden soil will improve soil structure, increase water retention, and provide a super habitat for good soil organisms like earthworms and beneficial bacteria.”

You can also used leaf mold as a compost, once the soil looks like crumbly black cake.

If you’re someone who doesn’t like to look at a rotting pile of leaves for a year, the master gardeners suggest packing a black plastic bag as full as you can with leaves. Before tying the bag, thoroughly wet the leaves with the spray from a garden hose. Next, poke some holes in the bag. Finally, hide the bag out of view and out of full sun. Sun will cause the bag to deteriorate. You can venture into the bag seasonally and give the leaves another good squirt of water.

Just about the time you have given up on the project, the leaf mold should be ready and good to use on your garden beds.

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