Let's Get Real About Sustainability in Gardens

Consider corn as a way to look at true sustainability. Corn plants produce a massive root system that consumes large amounts of moisture and nutrients. The root system forms quickly: by the time a corn plant has formed just eight leaves it has produced 15 to 23 main roots with a total of 8,000 to 10,000 lateral roots. A mature plant can generate roots that have “ramified” (grown through) as much as 180 cubic feet of soil. (As seen in my book Roots Demystified, 2009.)

Corn plants need lots of nitrogen, and leguminous plants, as long as they’re not too crowded can provide it with all the nitrogen required. In a “natural” garden, the ultimate goal would be to eliminate almost all imported nutrients and other “inputs”. Horse manure, cow manure, sacks of bone meal, blood meal, green sand, bat guano, phosphates, or many other options—all add additional fertility, can qualify as “natural,” but come with various environmental costs attached; such as mining, transportation, energy use, and wasted bulk.

As an example of the energy invested in nitrogen for corn, consider blood meal. According to the Food and Agriculture Organization’s regulations, blood is introduced into the (processing) tank as a coagulated mass, previously obtained by a steam-action process. Ideally, as much liquid as possible should be squeezed from the coagulum. Heating is initiated at 82°C (180°F) and progressively raised to 94°C (200°F) for about three hours, then elevated to 100°C (212°F) for 7 hours. (That’s a LOT of energy). Drying is complete when the final moisture level in the dried product is about 12 percent.

Choosing blood meal at the nursery or organic supplier really means making a very important environmental decision compared to “growing” nitrogen at home by planting legumes and tilling the young foliage into the soil.

No matter what your source of imported nitrogen, whether for soil preparation or as a summer application for growth. It’s most effective to spread it relatively far from the cornstalk itself in order to feed the massive width of the corn root system most efficiently. One method of doing this would be to fertilize between the rows rather than on the rows themselves or at the base of each plant. If you plant intensively, be sure to add plenty of nutrients for this hungry crop.

Thus the gardener has three choices: import nutrients for intensive yields, or use a wider spacing and/or, rotate your crops to cut down on the competition for available nutrients. Don’t grow corn in the same spot every year, as it will exhaust much of the nitrogen. Instead, alternate it with green manures—legumes like fava beans (the flowers pictured above) tilled into the soil to provide nitrogen from the atmosphere. A good green manure should be tilled in before too much blooming.

Let me know what you think.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

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Lessons From "Our" Droughts

As winter approaches, gardeners in the west now have three things on their minds—water, water, and water. Or, rather, the lack of it. The pale, arid shadow of a dusty drought now extends over much of the American west and southwest.

The drought, which has settled into much of the west over the past three years, doesn't make much noise. You can't hear the sound of the mud drying in the bottoms of empty reservoirs. You don't hear any noise from the leaves as they turn brown and fall off the trees in mid-summer. And you can't hear anything coming from the countless wells which have run dry.

The first drought for me, after moving to California, was the so-called Big Drought of 1975-1977. Our current drought, which has lingered for three long, parched years, has had its impact on wild lands, suburbs, and cities. Now, I get to improve my skills with gray water systems, drip irrigation, and xeriscape (drought resistant) planting techniques.

My first experiments with gray water systems—collecting water from sinks, showers, and laundries to irrigate fruit trees and ornamental landscaping—were during the 1970's drought. The systems I installed in the basements and crawl-spaces of clients throughout Marin county in those days were, in retrospect, a rag-tag, baling-wire collection of bizarre-looking gizmos. Now I’ve learned a lot more. See the photo on the left of a system designed with current “technology”.

In my experience, gray water is not a crisis-intervention scheme, but one of the many "tools" which allows my garden to flourish. The overwhelming feedback, and my personal experience, has been: "My plants are growing better with gray water than with any other water source."

I knew nothing about drip irrigation until the drought of the 70's. Again, the "Big" drought introduced me to a new gardening tool which has become commonplace in the 1990's. The technological advances in drip irrigation since I first started messin' with drip irrigation in 1975 have practically exceeded that of the revolution in the computer industry.

After experimenting with countless drip irrigation widgets and gadgets I've settled on my favorite emitter technology—in-line emitters. (As described in my updated edition of Drip Irrigation, For Every Landscape and All Climates. 2009) Unlike the more common punched-in emitter, which you buy separately and insert into a hole you've punched into solid drip irrigation tubing, in-line emitters come pre-fabricated inside the one-half inch drip irrigation hosing. On the right, see the interior of several emitters that become encased in ½-inch tubing. There is also a clear piece of tubing to reveal the emitter. All the real tubing is black or brown. Old-fashioned, punched-in emitters get brittle in the heat and sunlight and easily snap off during routine garden maintenance—which leads to tedious hours of repair. In-line emitters have nothing exposed to break off, are securely housed inside a sturdy one-half inch plastic tubing that'll take to abuse of weeding, gardening, and mulching, and are far less time-consuming since the emitters are preinstalled. With in-line emitters, I avoid the so-called "spaghetti" tubing which seems to somehow mysteriously move and knot itself and ends up resembling its namesake, a heap of tangled noodles.

The drought of the 1990's taught me how to plant so as to practically eliminate the need for drip irrigation. I've come to discover many ornamental Mediterranean plants are actually more drought-resistant than a lot of California native plants. There are small 18-year-old test plantings around my house which were planted at the beginning of our fall rainy season, and never irrigated again.

The first drought for me was the so-called Big Drought of 1975-1977. (By the way, how can a reduced amount of rain, be "bigger"? How can you have more of less?) Anyway, there have been plenty of "bigger" and longer droughts over the past 400 years. Tree ring analysis in the central portion of Santa Barbara county, the Santa Ynez Valley, indicates two periods of 60 years of drought (below "average" rainfall) since the 1500s

So, watch out, don’t count on a break in the drought.

Let me know what you think.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

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"Natural" Gardens?

Their really is no such thing as a natural gardener-made landscape. All gardens are constructs made by people, not by nature. Our gardens ultimately serve our needs, our sense of aesthetics. This means every gardener is really servicing their own ego. Our gardens do look nice, but they don’t really look natural. A natural garden would look as if nobody planted it or tends it. Therefore, a truly natural landscape would not satisfy most gardener's egos. If nobody recognizes the yard as the product of another person, nobody gets any compliments. A purely natural landscape would look so naturalized that most people would just walk by without noticing. The ultimate goal of an ego-free landscape designer or gardener would be a garden which no one identifies as manmade. But I've never met such a gardener.

Our gardens will always be a constant dialogue about the following terms: natural-like, naturalized, earth-friendly, sustainable (the latest buzz word), or environmentally-sound. Unnatural doesn't mean malevolent. We can have reasonably natural-like gardens that meet every definition of beautiful. Such landscapes are nice and unnatural.

Given that we are growing artificial gardens, exactly how natural-like can we get? More environmentally responsive than we may think. But the answers are in the details. Here's some pointers:

Gardeners usually try to do too much. Some yards have plenty of natural landscape to begin with. The typical approach is to remove almost everything that's there, buy a bunch of topsoil and plants and put completely new stuff back. Far from natural. And costly.

Don't even think of planting until you've fully realized the potential of what nature already provided. All that's often required is to selectively thin, prune or remove. The idea is to sculpt your existing plants to reveal their hidden form and texture. It's like Michelangelo carving away bits of stone to reveal the magnificence of the David.

Carefully trim limbs from a tree to reveal a serpentine or wonderfully-textured trunk(s). Or, shape existing native shrubs to reflect the line of a nearby tree or a distant hillock. Pull out weedy exotic shrubs to display the curve of a tree trunk, the rugged shape of an immense boulder or the multiple trunks of a large shapely shrub. Weed out exotic grasses to leave behind a scattered pattern of native grasses.

Or, as photographed here, carefully open up an odd-shaped hole in a tree's canopy to provide a slice of the distant horizon, a nearby lake or the silvery ocean. This is a garden in Big Sur, CA that is simply composed of trimming the upper limbs of a native coast oak (Quercus agrifolia) and a planted, but carefully placed Ceanothus spp. (known as tick brush or wild lilac, NO relation to the popular common lilac – Syringa vulgaris). This section of the garden is the closest to a constructed, native landscape I’ve seen.

Let me know what you think.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

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Mounds #2

Here's a drawing about mounds and swales I found. It might help with building the mounds I referred to in the previous blog. It may be too small. Try double clicking on the image for a slightly bigger view. I think I could post it on my web site in a bigger format if you like. Let me know. (It's from my first book - Designing & Maintaining Your Edible Landscape - Naturally)

Visit my web site to learn about my new book on drip irrigation and other gardening books.

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Mounds, not the candy

I like to plant trees and shrubs on constructed
soil mounds as opposed to planting them in
flat ground. If you’re working with slightly
heavy clay/loam soils, the mounding is
especially critical to preventing root or crown
rot (Phytophthora spp.—a fungal disease of the
upper portion of the roots, near the soil surface).
Many ornamental and fruiting tree and shrubs die
of crown rot without the gardener ever suspecting
the culprit. The fungus damages the sapwood,
either killing individual limbs or the entire plant.
Once the symptoms (pale-yellow, wilted leaves)
appear, it’s too late to do anything about it.

So, mounds help stave off root rot.

In areas where the summers are dry, make your
planting mounds in the fall; then all you have
to do in early spring after bare root roses, fruiting
and ornamental trees, and berries arrive is open
the winter wet soil enough to place the roots and
cover it with native soil. In areas where it rains in
the summer, wait until the soil drains after a rain
so that it’s moist, not wet.

Here you can see the cross section of a mound made
of composting chips and leaves from a tree service.
The mound is capped with six to ten inches of soil and immediately
planted. All plants are still planted on small mounds on the composting mound.

Based on my book Roots Demystified.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

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The Dutch Win

This is the last landscape I installed before moving to the Farallones Institute Rural Institute to run the Edible Landscape Program. I inherited the plans from a student of the Harvard School of Landscape Design. He specified a herbal lawn mix between the redwood rounds. I didn’t approve of the redwood rounds for the patio as I knew there was too much white sap wood for them to last very long. Nonetheless, I followed the plan. I had already seen the “herbal lawn mix” at a public display garden. I knew one section was always blocked off due to too much usage, spilled sodas (maybe), and unknown spillages and urines.

The mix was composed of: creeping thyme (Thymus serpyllum), dwarf yarrow (Achillea millefolium), Roman chamomile (Chamaemelum nobile, usually listed in catalogs as Anthemis nobilis), and Dutch white clover (Trifolium repens).

I dutifully planted the mixture between the rounds. A year later, only the Dutch white clover remained. It is an aggressive plant. When grown as walkways between vegetable beds as a nitrogen source, it requires constant attention to control its spread.

Luckily the clients have no children as clovers leave nasty stains and are very attractive to bees.

Yet, it did provide a nice green mosaic between the rounds.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

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Error in Paris

Last year I traveled to Paris. In one of the oldest parks in Paris was one of the oldest Sycamore trees in the city. This sign shows that all that history and current science has got it wrong about root growth. They need to read my book Roots Demystified. If they read it, they would understand that all tree roots are at least 1/2 times wider than the canopy (dripline). In a sandy soil the roots can grow three to seven times wider than the dripline.

I think the last paragraph talks about the root system and nutrients, but I can not read French. Maybe someone reading this blog could translate it for me and others. (Click on the image to get a full screen view to make it easier to read.)

Visit my web site to learn about my new book on drip irrigation and other gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert