BED
PREPARATION METHODS
Somewhere
along the way to a full gardening education, a few questions will occur to any
alert student of gardening:
Why prepare
garden beds? Don’t plants grow in the ground without any disturbance? Why churn
up the soil, when the earth can sustain us simply out of its own abundance?
Isn’t there a fellow in Japan who grows vegetables simply by
tossing seeds into the grass under his fruit trees? Why don’t we do the same?
The answers
are complex, but they all stem from a few key historical developments. For the
past 10,000 years or so, humanity has become increasingly enmeshed in and
dependent upon agriculture. For the most part, we have given up lives of
harvesting native food plants and animals and have concentrated on domesticating
and growing plants and animals that are nonnative or, at the very least, do not
naturally occur in wild ecosystems. The vegetable plants we have developed in
this process do not occur in undisturbed wildlands, anywhere. Sometimes they
escape and naturalize themselves in non-garden areas, but these areas are
virtually always already-disturbed ecosystems. Fennel is one example of a
garden plant that establishes itself readily in high-human-impact areas at Lost Valley and elsewhere. Even better examples
are the many garden “weeds” that colonize pathways, ditches, vacant lots,
sidewalk cracks, and roadsides all over our continent. Like our vegetable
crops, those plants accompanied European settlers here and spread wherever they
tilled or disrupted the ground.
Even more
than most nonnative plants occurring here, our vegetable crops have developed
in tandem with soil disturbance, and they depend upon some degree of it in
order to thrive. Ecologically, they could be considered “pioneer species,”
colonizing landscapes after disruption. In fact, we insert them as pioneer
species after causing disruption ourselves. In some cases, these pioneer
species can create their own self-perpetuating colonies, which may in fact
continue for a while without significant further intervention, but which
generally benefit from ongoing gardening activities. Despite their independent
nature once they have found a place in the garden, these volunteer vegetables (celebrated
in the Beetless’ YOU WON'T SEED ME) still depend upon initial soil disturbance
to become established.
That soil
disturbance can take many different forms. Choosing that form wisely can make
the difference between a relatively healthy soil ecosystem and a greatly
degraded soil ecosystem which ultimately yields little food, satisfaction, or
hope for future generations of food-growers. Here at Lost Valley, we attempt to cause as little soil
disturbance as possible while still providing favorable conditions for our
vegetable crops.
The soil is
a delicate, complex ecosystem, most of which we still do not understand. We do
know that each teaspoonful of healthy soil can contain more than 5 billion
microorganisms, consisting of up to 20,000 different species (estimates vary
from these figures, but everyone agrees it’s “a lot”). We also know that the
health of the soil and of plants growing in it depends upon these
microorganisms. Particular species of microorganisms can live only at specific
soil depths, and moving soil from one level to another kills many of those
microorganisms. Desirable soil structure and tilth, including the formation of
soil aggregates, results from the action of these microorganisms in combination
with macroorganisms, humus, proper amounts of moisture and air, plant roots, mycorrhizal
associations, and a whole host of other elements explained more eloquently in
books like The Soul of Soil: A Guide to
Ecological Soil Management (by Grace Gershuny and Joseph Smillie) and Start with the Soil (by Grace Gershuny)
than here. (For definitions of various soil-related terms like clay, colloids,
crumbs, humus, loam, mycorrhizal fungi, sand, silt, and tilth, see the
Beetless’ GARDENING GLOSSARY.)
Strategic soil
disturbance can aid in the incorporation of organic matter and nutrients,
improve drainage and aeration, and create places for new plants, but it also
comes at a price: it disrupts intact soil ecologies, which then need time to
recover.
In some
situations, “no-till” does indeed work. It is the ideal promoted by farmers
like Masanobu Fukuoka (see PERMACULTURE GARDEN), who has found success growing
“feral vegetables” (by most reports, rather strong-tasting) in his orchards
(reports also indicate that most onsite farmhands have relied on more
conventional, tilled, organic vegetable gardens for their “regular diet”).
“No-till” tends to work better in pre-established gardens than on land already
populated by either native or invasive plants—and then, only if any weeds that
come up can be hand-pulled easily. Lost Valley’s large amounts of quackgrass
and other rhizomatous weeds make sustained no-till an unrealistic choice in
most of our gardening areas. However, we do minimize or delay tillage whenever
possible. Many of our best vegetables are self-sown and volunteer, often
growing on their own in previously cultivated beds rather than demanding that
we prepare new beds for them. (YOU WON'T SEED ME lists
many crops which commonly self-sow in our area.)
We usually
choose a minimal tillage method involving forking but not heavy spading—a
modification of the biointensive approach promoted by John Jeavons in How to Grow More Vegetables. As in
Jeavons’ method, we are aiming to create raised beds where we concentrate
amendments, water, and care, guarding them from compaction and planting more
densely than we would plant a conventional flat, rototilled garden or field. However,
our shallow, rocky soils make Jeavons’ double-digging method almost impossible
to achieve here, since we can rarely penetrate two spade’s-depths—and also
counterproductive, since it would tend to bring more rocks and subsoil to the
surface, where we don’t want them. Instead, we generally cultivate to a single
tool’s-depth with a digging fork, which allows us to extract quackgrass and
other rhizomes in large pieces (without slicing them as a spade would do),
while gently loosening and lifting the soil and letting amendments placed on
the surface to be incorporated evenly within the top ten inches or so of soil.
(Usually these amendments consist of compost and/or composted manure, oyster
shell flower to boost pH and add calcium, and occasionally rock dust to add
minerals—see, again, the Composting and Soil
Fertility section.)
Raised-bed
gardening has many advantages. The combination of raised growing area and
lightening of the soil through concentrated addition of organic matter allows
better drainage (especially important in our heavy clay soils), so that beds
dry out and warm up faster in the spring. Especially in deeply cultivated
raised beds, plant roots can spread downward rather than laterally, allowing
much closer spacing. Plants have better sun exposure, while shade-loving plants
are also easier to plant close to—and in the shadow of—larger sun-lovers
because of their closer spacing. By concentrating fertility and care, raised
beds can make best use of available resources. The closer spacing of plants not
only leaves less room for weeds, but also reduces water loss by shading the
soil. Meanwhile, the spongy texture of adequately-amended and
properly-cared-for raised bed soil not only facilitates drainage, but helps
hold needed moisture during dry periods. It is little wonder that the Beetless’ SHE SAID RAISED BED is one of their most optimistic, upbeat numbers.
Nevertheless,
the reality remains that we have a A HARD CLAY SOIL. Without a massive
importation of loam and extra organic matter, our beds still have a long way to
go before they resemble those dreamlike, deep, spongy, fertile beds that Alan
Chadwick (John Jeavons’ biointensive mentor) created at UC Santa Cruz and Green
Gulch Farm. We do not have the resources available to import the soil and
materials needed to create ideal gardening conditions here; instead, like most of
the rest of the world, “what we’ve got is what we’ve got” (to paraphrase the
Beetless), and we are working to improve it rather than hoping to trade it in. We’re
thankful that, despite its drawbacks, clay does have higher nutrient-holding
capacity than coarser particles like sand.
Flat particles of clay are also much more easily
compacted, especially when wet. Compaction is always undesirable, since it
squeezes air out of the soil, reduces the soil’s ability to hold nutrients,
reduces the capacity for drainage, and makes it more difficult for seeds to
sprout and for plant roots and rootlets to spread. Beds should be no wider than can be easily accessed from either one side
of the bed or the other, so that gardeners walk, stand, kneel, crouch, sit, and
lie only in the paths between beds. (If beds are particularly wide or
accessible from only one side, stepping stones can be placed to allow access
further in.) It is usually easiest to cultivate or harvest from just one half
of a bed at a time, using the path immediately adjacent to that half, and
coming down the path on the other side to reach the other half of the bed. In
sum, unless we want to ruin our soil structure and make pottery instead, we are
well-advised to listen to the Beetless’ plea on behalf of their garden beds:
DON’T STEP ON ME. (Curiously, this song, like this advice, was not always
well-received by those who heard it—“another case of rubbing fans the wrong
way,” is how the APPENDIX puts it. The gentle art of staying positive and
supportive while trying to protect raised beds from being compacted is an
ever-evolving one, in which we can safely say that no compassionate yet
conscientious gardener has yet achieved perfection.)
Working the
soil when it is too wet is another way to cause compaction. If the tines of the
fork leave visible marks (shiny compacted surfaces) on the soil, the soil is
too wet to work. If you can pick up a handful of soil, squeeze it together, and
drop it onto the bed without it crumbling easily back into soil, then it is too
wet to work. If you can mold it into pottery, it is too wet to work—or else it
is part of the clay subsoil, not the topsoil you are wanting to garden in. Soil
can also become too dry to work with ease; if penetrating the surface with a fork
seems like a daunting chore, the soil probably needs more moisture. Ironically,
working the soil when it is too wet will cause it to become even more difficult
to work when it is too dry, since the smushed-together clay particles will form
a hardened, baked, almost concrete-like texture when they dry out. If you need
to moisten too-dry soil in order to work it, do so carefully; you can hand-water
lightly, or water long enough in advance that the bed has a chance to dry out
adequately before working. Thinking ahead about proper soil moisture for bed
preparation, and then timing watering and other activities accordingly, is an
essential, learned skill that will prevent both the unnecessary work of
flailing away at soil that has baked too dry, and the destructive work of
cultivating soil that is too wet.
Hand-tillage
is almost always more gentle on the soil than mechanical cultivation.
Rototillers destroy soil structure by pulverizing the soil, and also create a
hardpan (a zone of compacted soil) at the depth of the tines. (The tiller-depth compaction and much of the
rhizomatous weed problem in some of our garden areas can be traced directly to
past use of both tractor-hauled and hand-pushed tillers. Rototillers are also,
hands-down, the most effective way to break up, multiply, and distribute
quackgrass and other rhizomes, as well as vigorous perennial roots such as
comfrey, each piece of which can develop into a new plant.) Among tractor implements, discs are far less destructive to soil than
the old moldboard plow, but still can cause compaction and disturbance of soil
layers, not to mention the toll they can take on life forms ranging from soil
microbes to ground-nesting birds to charismatic rodents and rabbits). Judicious
use of subsoilers and various other mechanical aids can be helpful in
establishing or maintaining food-growing areas, but mechanical tillage always
has its downsides. The Beetless celebrate the use of hand-tools in I WANT TO DIG BY HAND, while also cautioning, in SHE DUG YOU, that even hand tools can
wreak terrible destruction when improperly used. Poorly-executed and
poorly-timed double-digging can upend and compact soil while destroying much of
its life; as the Beetless’ sing, “When you’re dug like that, it makes me really
sad.” The farmer who sings I TILL has even more to regret, offering a litany of
errors and tales of destruction resulting from the fact that “’cause I’m
‘xpected to, I till.” As the Beetless’ APPENDIX explains, their own romance
with tractors was short-lived, and DRIVE MY TRACTOR was unceremoniously dropped
from their repertoire.
One more
method of bed preparation bears mention here: mulching. In existing beds, mulch
refers to any material applied to the surface of the soil to provide nutrients
and organic matter, to prevent evaporation of moisture, to reduce weeds, to
prevent soil erosion (see YOU'RE GONNA LOSE THAT SOIL), and/or to moderate,
raise, or reduce soil temperature. Dark materials applied as mulch will convert
sunlight into heat; they are sometimes used to induce better fruiting and
ripening of heat-loving “American” crops, although, depending on when, where,
and how thickly they are applied, they can also serve to insulate soil and keep
it from warming up. Light-colored materials, on the other hand, will keep the
soil from converting as much sunlight into heat, while reflecting more of it
back onto plant leaves.
We have spread compost and/or composted manure as mulch on beds when incorporating it
immediately is not possible or desirable because of either excess soil moisture
or pre-existing plants. We typically mulch our garlic beds with hay after
planting in the fall, which both suppresses weeds and helps hold in moisture;
sometimes this means that we need to water only once (or not at all)
before harvest in July. We have shaded seedbeds with mulch to help hold
moisture in until sprouting. A frequent downside of mulch is that is provides
perfect habitat for slugs, which love to eat our vegetables. We tend to not use
mulch around any crops that are slug-susceptible, especially when slugs are
also plentiful. (See HERE COME THE SLUGS.) We also avoid mulching beds that we
are eager to dry out so that they can be worked, especially in the spring.
In general,
“nature abhors bare soil.” Just as the close plant spacings of biointensive
gardening prevent excessive bare soil, so too can mulch. As mentioned above, in
certain circumstances (usually related to drying beds, warming soil, or keeping
pests at bay), we do want bare soil, but in most cases, soil life thrives and
erosion is avoided when the surface is covered with plants and/or decomposing
organic matter.
Mulching
can also be used to convert areas not recently gardened (or never before
gardened) into garden beds. This is called “sheet mulching,” and usually
consists of laying down layers of various materials intended to suppress
whatever is growing underneath them while providing fertile conditions for new
plants to grow. Cardboard or newspaper is usually used as a first layer,
although, in PAPERBACK MULCHER, the Beetless claim that paperback books work
just as well. Various types of organic matter and minerals can be layered on
top. In general, the thicker the mulch, and the more closely it’s monitored,
the more effective it is in achieving desired results. In areas of particularly
persistent perennial weeds, mulch that is not deep enough (and even some that
IS quite deep) can have the opposite effect: it succeeds in suppressing the annual
weeds, but just makes the perennial weeds stronger. Rhizomes form thick
networks underneath the cardboard before bursting through cracks into the
luscious fertilizer above, and large perennial root masses also have plenty of
stored energy to bide their time. This has happened to us, more than once—some
of our worst perennial weed patches are the results of sheet-mulching
experiments gone awry. On the other hand, with adequate inputs of organic
matter and labor (to persistently remove resprouting perennial weeds), a
properly-managed sheet mulching project can be an excellent way to rescue or
create new growing areas. Potatoes grow particularly well in sheet mulch, and
are easier to harvest at the end of the season than potatoes grown in straight
soil (which is why I DIG A POTATO disappeared from performance repertoires and
is remembered only through a mention in the Beetless’ APPENDIX).
The multitudinous functions of mulch
find enthusiastic expression in MULCH!, which takes a bed’s-eye view of the
subject. IT'S ALL GOOD MULCH delves into some of its many possible forms and
sources, bookended by Joychoi’s hypnotic drone: “It’s all good mulch, for me to
take, organic matter all around me.” For more mulch-pertinent information, we once again recommend referencing the Composting and Soil
Fertility section.
(forward to Pt. 6) (back to Gardening Guide index)