Decades before the terms
“eco-friendly” and “sustainable growing” entered the vernacular, How to Grow More Vegetables (Ten Speed Press, 2012) demonstrated
that small-scale, high-yield, all-organic gardening methods could yield
bountiful crops over multiple growing cycles using minimal resources in a
suburban environment. The concept that John Jeavons and the team at Ecology
Action launched more than 40 years ago has been embraced by the mainstream and
continues to gather momentum. Today, How to Grow More Vegetables, now in its fully
revised and updated 8th edition, is the go-to reference for food growers at
every level: from home gardeners dedicated to nurturing their backyard edibles
in maximum harmony with nature’s cycles, to small-scale commercial producers
interested in optimizing soil fertility and increasing plant productivity. In this excerpt from chapter 1, “Deep Soil Creation and Maintenance,”
discover how to create good soil structure for your raised bed garden.
Buy this book in the GRIT store: How to Grow More Vegetables.
preparing your raised beds is a great way to get healthier soil. A
well-prepared bed will rejuvenate your soil structure, and proper soil
structure and sufficient nutrients allow uninterrupted and healthy plant
growth. Loose soil enables roots to penetrate the soil easily, and a steady
stream of nutrients are allowed to flow into the stem and leaves. Plants close
together in narrow beds are easy to cultivate and harvest, and closely spaced
plants benefit from a good microclimate and healthy soil.
initial preparation and planting of a raised bed may take 6 1/2 to 11 hours per
100 square feet. If you are lucky enough to have loose soil, the time
commitment will be less. No matter how long it takes, the time invested pays
off with increased yields and healthier soil and plants.
you become more skilled at double-digging, and your soil becomes healthier, the
time invested is greatly reduced. Often a 100-square-foot bed can be prepared
in two hours or less. We estimate that only 4 to 6 1/2 hours should be required
on an ongoing basis for the entire bed preparation and planting process as the
soil develops better structure over time with correct care and compost.
of the trade
recommend investing in quality tools from the beginning — poor tools can be
tiring and discouraging — but do whatever gets you started. Experiment with
short D-handled and long, straight-handled tools to figure out which you like
best — some folks find that D-handled tools allow them to work more
efficiently, while some like the extra leverage and upright posture that long
handles allow. A 5/8-inch-thick plywood board, 2 to 3 feet long by 3 to 5 feet
wide, serves as a “digging board” to stand on. A digging board will spread your
weight out so that you compact the soil less when standing on the bed area. You
can treat the board with linseed oil to protect it against soil moisture, if
you like. A bow rake makes leveling and forming the bed easy. If you don’t have
one, hula hoes are the perfect tool for cultivating the upper 2 to 4 inches of
soil around closely spaced plants.
a raised bed
choose a place for your raised beds that has access to water and sunlight — preferably
7 to 11 hours of direct sunlight each day. To begin, mark out a bed 3 or 4 feet
wide and at least 3 feet long. A 3-foot-square space is big enough to form a microclimate
beneficial to your plants and the soil. Longer beds are popular, but make sure
you can easily reach the entire bed without standing on it.
best time to double-dig the soil is early morning or evening during spring or
autumn. The cooler air temperature helps preserve soil life. Dig only when the
soil is evenly moist — it’ll be easier for you and better for the soil. Soils
that are too wet are easily compacted, and compaction destroys friable
structure and minimizes aeration. These conditions harm the beneficial
microbiotic life that your plants need to thrive. Soils that are too dry tend
to be hard and difficult to dig, and good soil structure will be difficult to
maintain if your digging results in just so many brick-like clods.
the soil by forming a ball in your palm. Soil is too dry for digging when it is
loose and will not hold its shape after being squeezed in the palm of your hand
(in cases of sands or loams) or when it cannot be penetrated by a spade (in the
case of clays). Soil
is too wet when it sticks to the spade as you dig.
goal of double-digging is to loosen the soil up to 2 feet below the surface.
The first year, you may be able to reach only 15 to 18 inches with reasonable
effort — that’s just fine. You don’t have to hurt yourself to have a good
garden. Nature, the loosened soil, worms, and plant roots will further loosen
the soil with each crop, so digging will be easier each year and the depth will
increase over time. Be patient in this soil-building process. It
takes 5 to 10 years to build up a good soil (and one’s skills). Actually, this
is very rapid; it takes nature thousands of years to build the 6-inch layer of
topsoil needed to grow a good crop of food. After the soil has been initially prepared,
you will find that the double-digging method requires very little work per unit
of food produced. The Irish call this the “lazy bed” method of raising food.
good soil structure is established, you can simply cultivate the top 2 to 4
inches. Another way to keep soil light and airy is to single-dig, or loosen the
top 12 inches with the spading fork. Single-digging between crops in the same
growing year will help improve your soil faster.
check the soil moisture. The soil should be evenly moist to facilitate digging,
but not saturated. If needed, water the area to be dug. For hard, dry clays
that have not ever been cultivated, this may mean up to 2 hours with a
sprinkler. Begin the next steps when soil is evenly moistened.
a layer of compost over the entire area to be dug and place the digging board on
the bed, leaving a foot or two from the end of the bed for the first trench. Be
sure to dig trenches across the width of the bed. Remove soil from the top foot
of the first trench with a spade. Set this aside, and try not to turn it over —
most of the beneficial microbes are in the top 6 inches of the topsoil.
in the trench or on the digging board above the trench, dig down another 12 inches
(or as deep as possible) with a spading fork, a few inches at a time if the
soil is heavy or tight. Try not to turn the soil over too much, just lever the
tines through, loosening large chunks. If necessary, toss large clods a little
bit, allowing them to fall on the tines and break; you can also stab clods with
the fork and lever them apart.
loosening the first trench, move the digging board back and dig the next
trench, moving each spadeful of the top 12 inches of soil forward into the
first trench. When digging, make as few motions and use as little muscle as
possible in this process. As you dig the soil, you will discover a smooth
rhythm in which you are virtually just shifting your balance and weight rather
than straining your back and arms. Repeat the subsoil-loosening process in each
trench before moving on.
the topsoil with a rake every three to four trenches will help you maintain an even
depth and good drainage. Notice how, as you dig, some of the compost you spread
on the bed slides down into the trench. This approximates the way nature adds
organic matter and will quickly enrich the entire depth of your soil.
make sure that the upper layer of soil (the top 12 inches) is not turned over during
the double-dig. Try to aim for a balance of loosening the soil, while not
mixing it too much, to preserve the natural structure of your soil.
digging, the bed will often be 2 to 10 inches higher than the soil’s original
good soil can contain around 50 percent air space, allowing for increased
diffusion of oxygen (which the roots and microbes depend on) into the soil and
of carbon dioxide (which the leaves depend on) out of the soil. The increased “breathing”
ability of a double-dug bed is a key to improved plant health. To prevent
erosion and promote more even water saturation in a clay bed with a high rise,
you can create a small soil lip around the top of the bed.
— more is better
may choose to add compost at different points when double-digging. Instead of
applying compost only after the double-dig, consider spreading a 1/2-inch layer
over the bed before digging and/or a 1/2-inch layer into the trench during the
Your friend, the broadfork
The U-bar, or broadfork, can
be used as a substitute for the ongoing double-dig for soil that is in reasonably
good shape. The broadfork is quicker and easier than using a spade and a spading
fork. The broadfork tines don’t disturb the soil as deeply as a double-dig, but
the lower region of the soil compacts more slowly than the top, so it’s often
sufficient. It aerates the soil less than a full double-dig, which is an advantage
in looser, sandier soil and can be a problem in tighter clays. If you use a
broadfork regularly, only double-dig as often as required to keep your soil
light and fluffy.
Good soil structure
As your soil improves and
the large clods disappear, your bed may not raise as high as initially. Do not
worry about this. It is a sign that you and your soil are successful. The goal of
double-digging is not the height of the bed, but a reasonable looseness and
good structure of the soil.
To check your structure,
squeeze some slightly moist soil firmly in your hand, then open your hand. If
the soil falls apart easily, it does not have good structure. If it holds the shape
of your hand even when you press it gently with the fingers of your other hand,
it does not have good structure. If the soil breaks apart into small clumps
when you press it with your fingers, it probably has good structure.
Remember that structure is
different from texture. The texture is determined by its basic ingredients:
silt, clay and sand particles. The soil structure is the way these ingredients
hold together. With your assistance, sticky “threads” exuded by microbial life
and the roots produced by the plants help to loosen clay soil and improve sandy
Once the bed is prepared,
you will truly appreciate its width. A 3- or 4-foot-wide bed can be fertilized,
planted, weeded and harvested from each side with relative ease, and insects can
be controlled without walking on the bed.
This width also allows a
good mini-climate to develop below closely spaced plants. You may wish to use a
narrower bed, 1 1/2 to 2 1/2 feet wide, for easier harvesting of trellised plants
like tomatoes, pole beans and pole peas.
Try not to step on the
growing beds once they have been prepared. This compacts the soil and makes it
more difficult for the plants to grow. If the bed must be walked on, use the double-digging
board. This will displace your weight over a large area and minimize the damage.
Plants obtain much of their water and nutrients through the contact of their
root hairs with the soil. If they do not develop an abundant supply of root
hairs, less water and fewer nutrients are taken in. The root hairs are more numerous
and vigorous in looser soil, so keep your soil loose.
When weeding, note that the
entire weed root usually comes up out of loosened raised bed soil. This is easy
weeding, and if you get the entire root, next year will be even easier.
The living mulch shade cover
provided by mature plants helps to keep the soil surface moist and loose. If
the soil compacts between young plants before the microclimate takes effect,
you can cultivate to fix the problem.
Once your beautifully alive
bed is prepared, keep it evenly moist until and after planting so the
microbiotic life and plants will thrive. The bed should be planted as soon as
possible after digging to take advantage of the new surge of life made possible
by bringing together the soil, compost, air, water, sun and fertilizers.
excerpt is reprinted with permission from How to Grow More Vegetables: And Fruits, Nuts, Berries, Grains, and Other Crops by John Jeavons and published by Ten Speed