The last bed

What a sense of satisfaction to complete the initial double digging in the garden this week! It’s taken me two years to do all of the beds at least once, which is the first point I want to make today. You don’t have to tackle double digging the whole garden all in one go. Try doing one bed a year, if that is all you’re up to. I dug three of my 12 main beds last spring, three in the fall, and the last four this spring. That was a challenging pace for this moderately fit 63-year-old! Nevertheless, now that the job is finished for the season, I’m going to miss the daily workouts.

The method of burying straw in the trenches, mixed with a handful of fresh grass clippings, is an old technique that goes way back in the biodynamic tradition. I’ve been calling it my “poor girl’s compost,” because straw is relatively inexpensive compared to finished compost. Another advantage is that I can carry a bale in the back seat of my Honda Accord more easily than I can haul loads of compost. (Later, as we establish the crop rotation, we’ll be able to use cover crop grown on the same bed for this purpose, reducing the inputs we bring in from outside the garden.)

Hardpan
The “hardpan” line I encountered about 12-inches below the surface of the soil.

Underneath the straw, I have forked through the hardpan—a compacted layer about 12 inches below the soil surface—created by many decades of tractor tillage with a moldboard plow. Notice the distinct line created by the tractor as it worked the soil to a specific depth over the years.

The straw will quickly break down over the next couple of months, and will be incorporated into the gray compacted layer with the help of earthworms and the water freely percolating down into this layer for the first time. By the time I dig it again in the autumn, that layer will be indistinguishable from the black soil on top of it.

I want to show you the contrast between the soil structure of this first dig and that of a nearby bed that has been dug three times over the past year.

Soil Structure
Soil structure of a bed freshly double dug for the first time (left) vs. one that has been dug and amended with compost several times (right).

You can see how the compaction affects the texture of the newly dug soil. Low in organic matter, it is characterized by tight shards that shatter into fine powder when you crush them in your hand, only to form a new hard pack when it gets wet. This will soon change, as you can see from the texture of a nearby bed that has been double dug and amended with compost several times. The more mature bed has a crumbly texture made of soft, humic, aggregates that gently hold together, and stay loose even after a hard rain.

The unique result of double digging is that this new, life-rich, texture is consistent down through 20-inches, or more, of the soil profile. It is a joy to work with, and not difficult to maintain going forward.

Freshly Prepared Biointensive Bed
This Biointensive garden bed has just been amended with two inches of compost, balanced with natural fertilizers (based on a recent soil test), and is ready to plant.

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