COMPANION
PLANTING
Picture a
patch of wild land. Then picture a modern agricultural landscape. Are they any
different?
The patch
of wild land is likely to host a diverse range of plant species, of varying
ages, occupying a multitude of different niches. It hosts diverse animal
species as well, from worms, insects, snakes, birds, and mammals down to
microorganisms. It is likely to have an “organic” feel to it, displaying a much
more artful, complex, chaotic “order” than is generally evident in
human-designed landscapes.
By contrast
the modern agricultural landscape is likely to consist of one plant species for
acres at a stretch. Animal species diversity is minimal, tending toward animals
considered “pests.” The landscape probably has an “industrial” or even
“military” feel to it, consisting of straight lines and rectangles. If it is a
typical modern large farming operation, it embodies the antithesis of wildness.
Food-growing
didn’t always stand in stark contrast to wildness. It grew out of wildness.
Until the advent of industrial agriculture, most gardens and farms were almost
infinitely more diverse than today’s typical large-scale monocultures.
Large-scale machine- and chemical-intensive farming predisposes one to certain
“garden designs,” consisting almost exclusively of large patches of the same
plant. But human-scale gardening, especially with hand tools, predisposes one
just as strongly to diverse planting schemes and to a much closer emulation of
natural “wildness.”
In natural
ecological communities, many different varieties and species of different-aged
plants coexist and thrive in symbiotic relationships. In keeping with
Permaculture principles, the more closely we can replicate this kind of
multigenerational diversity in our gardens, the healthier and more productive
those ecosystems too are likely to be.
Preparing
beds by hand means that we can leave still-productive plants in our garden beds
when we prepare them for new crops. Perennials, biennials, seed crops, and
volunteers can thus coexist with newly-planted vegetables. If any of those
older individuals are ready to take out later, we can always remove them,
cultivate, and replant their portions of the bed when their time has come.
Even within
our new plantings, we can foster multigenerational diversity. Gardening books
speak frequently of “companion planting,” but many gardeners may fail to
realize just how many ways plants can be companions, and how widely
companion-planting principles can be applied. In some of the best-known
examples, certain companions emit chemicals that improve one another’s flavor,
or attract beneficial insects that will discourage one another’s pests. (In
fact, diversity in general will attract beneficial insects, confuse pests, and
reduce pest damage.) But companions may also skillfully share habitat by having
complementary aboveground and belowground space requirements, complementary
nutrient requirements, complementary water requirements, and complementary
needs for sunlight. In other words, low-growing and taller plants, deep-rooted
and shallow-rooted vegetables, sun-lovers and shade-lovers, and those whose
preferred pallets of nutrient and water intake do not compete with one another,
will very happily coexist, as they do in natural landscapes.
Quick-growing
short-term plants and slower-growing longer-term plants can also be perfect
combinations. We frequently plant longer-term cooking greens, many of them
biennials that will survive overwinter and continue producing into the spring,
such as cabbage family members and chard, in a grid pattern which will provide
optimal spacing once the plants are full-size. In between them, we plant salad
starts such as lettuce, arugula, tah tsai, bok choy, spinach, etc., most of
which will be ready to harvest quite quickly, and which will be ready to remove
from the bed by the time the longer-term plants need the room. Mizuna mustard
straddles the line between “short” and “long” term—it is a fast-growing salad
green, but it also works as a cut-and-come-again vegetable that will last for a
while before it exhausts itself and flowers. Even brassicas that may complete
their cycle within the first season of growth, like certain cabbages, broccoli,
and cauliflower, are suitable “longer-term” foundation plants in between which
one can plant salad greens. Especially in the summer, salad greens appreciate
the shade provided by larger plants—they can even be planted into a bed in the
shadow of already-established plants with great success.
Summer and
winter squash, cucumbers, and tomatoes are all plants around which salad greens
can thrive before these larger plants have attained their full size. Squash,
especially, is planted with significant distances between clumps, so a bed of
squash can easily yield nearly a bed’s worth of lettuce before the squash
plants get large enough to cover the entire area. Salad plantings between and
underneath tomato plants are generally a bit less productive (because the
tomato plants are transplanted at a larger size, and closer together, than the
squash), but nevertheless produce salad that one would not otherwise have.
Salad plantings between rows of newly-sown root crops can also yield
abundantly—and/or rows of root crops, peas, or beans, can be sown between salad
greens that will be harvested by the time the new plants need the space.
Root crops
themselves can be companion-planted with one another. Radishes are typically
sown in the same furrows as carrots, because they sprout and grow quickly and
help shade and protect the slower-sprouting and –growing carrots until the
carrots need more space. Radishes are also often sown with parsnips, which take
even longer to germinate and grow. In both cases, the radishes must be
harvested with care to avoid disturbing the longer-term crop, but the
longer-term crop undoubtedly benefits from this arrangement, as do the radishes
(which get their day in the sun) and the gardener (who doesn’t have to fuss as
much over the carrots or parsnips, since the radishes are helping to keep them
moist and protected during sprouting).
As usual,
the Beetless have something to say about all this. I'VE JUST SEEN A PLACE
recites a litany of companions taken from published gardening texts, and,
perhaps more importantly, notes some of the qualities that make crops good
companions. It also sheds light on “antagonists,” a small handful of plants
which actually discourage one another’s growth. We don’t place much emphasis on
plant antagonism in our garden planning here, although we do try to keep fennel
out of most of the garden beds, because of its reputed allelopathic
(plant-growth-inhibiting) properties.
As for
spacing between plants, the simple formulas and recommendations presented in
seed catalogs and gardening books cannot always be strictly applied to diverse
companion-planted beds. Even for single-crop plantings, recommendations vary.
We tend to consider the different recommendations, and also factor in how many
plants are ready or needing to be transplanted and how much bed space is
available. All other things being equal, we tend to use spacing somewhere in
between the dense plantings recommended in Jeavons’ How to Grow More Vegetables and the more widely space plantings
recommended in the Territorial Seed Company catalog. Whenever possible, we tend
to plant in the offset “grid” or “honeycomb” pattern described in Jeavons’
book, by which more plants can fit in a bed because the basic spacing pattern
is based on a triangle rather than a square. In other words, the plants in each
row are placed equidistant from two
plants in the adjoining row, rather than lined up with one of them, meaning
that the rows themselves can be closer together. (If you are still confused,
consult the diagrams in Jeavons’ book.)
Crop
rotation is a well-known form of “companion planting over time.” Gardening
books give various prescriptions for crop rotations, which generally involve
alternating the growing of heavy feeders (plants which make large nutrient
demands on the soil), light feeders, and “givers” (plants which help provide
nutrients to the soil). Crop rotation can also reduce the danger of pest and
disease problems by not allowing their buildup in association with plants that might
otherwise grow year after year in the same area. Because our garden areas are
often so diverse, strict crop rotation formulas often do not directly apply; we
have enough diversity in many beds throughout the course of a year that
following with similar crops in the following year does not cause any problems.
Strict crop rotation is most important in the case of monocrops, and is also essential
when observed pest or disease buildup indicates that it is necessary. As a
general rule, we try to rotate crops and “mix it up,” but we don’t get too
stressed when we realize that many of the twenty different varieties of
vegetables which are growing in a bed were also seen there sometime in the
previous year. Diversity helps healthy plant communities thrive in the same
place much longer than homogeneous communities ever could. The continued
flourishing of some volunteer vegetables in similar locations year after year
(see YOU WON'T SEED ME) is proof that dogmatic adherence to crop rotation
formulas can be not only unnecessary, but self-defeating, evidence of Small
Thinking that would eliminate plants that “know where we want to be…we’re the
best nutrition, and we grow for free.”
(forward to Pt. 8) (back to Gardening Guide index)