PROPAGATING
CROPS FROM SEED
The
experience of planting a seed and watching it grow into a mature plant is a
window into mystery like few others. It never fails to evoke feelings of
wonder and awe in those who stop to contemplate it, or who simply let the
reality of it sink into their bones. How can so much information be contained
in such a tiny package? Of course, this same miracle of life operates all
around us, among all creatures which reproduce.
Scientifically, we know that DNA in
the nucleus of cells contains the information that determines the
characteristics of living organisms as they attempt to ensure that their genes survive
beyond their individual deaths. We can read about this phenomenon, and even be
amazed by it intellectually. The term “seed” is tossed around freely in our
language as a metaphor. Whether sprinkled on a hamburger bun or as the basis of
whole-grain meals, edible seeds are part of most of our daily lives. And yet,
for a deep “grokking” of what a seed is, few experiences can match that of
actually taking a seed in one’s hand, planting it, and watching what happens.
Many spiritual traditions and rituals (particularly those of indigenous
agriculturalists) have arisen from the miracle of the seed, which continues to
inspire mystical revelations even among those who did not grow up in religious
traditions explicitly grounded in the earth and its cycles. It takes only a
little planting experience to understand the appeal of the Beetless’ anthem, ALL YOUR SEEDS ARE LOVE.
Many gardeners buy vegetable starts
to transplant into their gardens, but those who do so miss out on a crucial
first step. Starting crops from seed can involve some additional work and
require extra attention, but it can save significant amounts of money, and,
more importantly, exposes gardeners directly to the miracle that ultimately
underlies our food-growing activities. At Lost Valley, we raise all of the crops we can
from seeds that we sow ourselves, although we sometimes plant transplants as
well (usually excess transplants donated to us).
When possible, we save our own seeds
and start our crops from those. (See the Seed Saving section.) We also plant
many donated seeds and seeds acquired at seed swaps. Whenever possible, we use
organically grown, open-pollinated seeds. Specific information on seed viability is often listed
on seed packets, and is also available in seed catalogs and books such as
Suzanne Ashworth’s Seed to Seed. Some
types of seed are relatively long-lived (many brassicas last five years or
more), while others are notoriously short-lived (leeks and onions may not last
more than one year). Storage conditions greatly influence seed life and vigor.
In general, keeping seeds dry, cold, and dark, while still able to “breathe,”
ensures the longest viability. This combination of conditions can be challenging
to achieve in our Pacific Northwest climate: dryness and cool do not normally coexist here.
During the colder parts of the year, the air is typically quite moist, while
low humidity coincides with the relatively warmer temperatures of our dry
summers. Ideal storage conditions would involve storage in a freezer of seeds
that have been adequately dried. We have usually made do with storage in large
mouse-proof but somewhat breathable plastic bins that we try not to let get too
hot or too moist.
When sowing in flats (where most of
our seed-starting is done—see the Transplanting and Direct Seeding section), we
have used either pre-mixed organic soil medium or a mixture we prepare
ourselves. We have typically sown seeds in lines in several-inch-high square or
rectangular wooden or plastic boxes, with drainage holes or slats on the bottom,
and a layer or two of newspaper to keep the soil mixture from falling through
the openings. In LOOSELY FIRM THE EDGES OF SEEDFLATS, the Beetless describe one method of seed sowing: sifting compost,
adding amendments, filling seedflats with the resulting mixture, tamping the
edges, then sowing seeds in furrows and covering them.
Sowing seeds in rows in flats, for
later pricking out into larger containers, has several advantages: it conserves
space in the greenhouse, allows the extra attention (including watering and
protection from birds) needed for sprouting seeds to be concentrated in a small
area, and allows selection of the healthiest individuals when pricking out
(while not wasting space in six-packs or plug trays on nonviable seed). It also
gives the seedlings, once planted in the larger containers, a head start on any
weeds, and minimizes the amount of bare soil exposed at any one time (bare soil
needs more frequent watering, and, without the close proximity of neighbors,
individual plants in larger containers are more likely to be stressed by heat,
cold, etc. when they are small). It also eliminates the need for thinning
six-packs or plug trays in which more than one seed has sprouted per cell. For
the reasons listed above, John Jeavons’ How
to Grow More Vegetables advocates the traditional biointensive step-by-step
approach, giving plants progressively more room through several stages as they
grow—but other approaches are certainly possible. Many commercial operations
which have no shortage of space or of larger planting containers and no problem
with bird predation, and which have watering systems which can easily keep many
sprouting six-packs or plug trays moist, choose to eliminate the extra labor
step of pricking out. Smaller-scale gardeners, too, may choose this option. (For
further discussion of pricking out and transplanting, see the Transplanting and Direct Seeding section.)
For each crop, seed catalogs and
packets typically recommend how many seeds to sow per inch when planting in rows or broadcasting—usually denser than
the final spacing (plants will be pricked out or thinned later). If you’re
using older seed, which may have a lower germination rate, it’s wise to sow
even more thickly than recommended for new seed. Larger seeds are easily
individually placed by hand in furrows or pots. With smaller seeds, a “sprinkling
method” can be effective: seeds can be held between thumb and forefinger and
released by gentle rubbing, or can be gently sprinkled from a palm, packet, or
other container. Special seeding boards (with holes punched at appropriate
intervals) are sometimes used with plug trays, and mechanical seeders can be
used for longer rows in garden beds. Cover crop seeds are usually broadcast by
hand, and mechanical seeders are available for this operation as well.
How deep should seeds be planted?
This depends on the individual seed, as well as several other factors. Seed
packets and catalogs usually recommend certain planting depths for specific
crops, but a good general guideline is to cover the seed with about two to
three times its diameter in soil. Of course, this will vary. Some seeds, like
lettuce, need to be quite shallow in order to germinate—they need some exposure
to light, so should be covered with the thinnest layer of soil that will allow
light to penetrate while not allowing the seed to dry out (or be plucked away
by a bird) on the surface. Shallow planting is also recommended in heavy clay
soils, and at times of year when the soil is apt to become waterlogged and/or
cold. On the other hand, deep planting can ensure better survival in
well-drained soils and in dry and/or overly hot conditions. Here in the Pacific Northwest, especially when the soil is wet
and somewhat cool, we will get better results if we plant large seeds like
beans and corn relatively shallowly. In the arid Southwest, however, the Hopi
traditionally plant their nonirrigated beans and corn quite deep, where they
can benefit from the small amounts of moisture that their “planting hole”
method helps collect, and be protected from the drying effects of the hot
desert sun.
Other
factors influencing planting
depth can include expected weather conditions during the period of
sprouting,
whether the seed has been presoaked and presprouted, whether birds,
slugs,
gophers, or other potential visitors have been or may be expected to be
active (see HERE COME THE SLUGS, GOPHER BITES, and ACROSS THE SEED BEDS FIRST),
and what medium is being used to cover the seeds, any of which could
dictate
shallower or deeper planting. Seeds on or near the surface of outside
beds may
be washed away in a downpour, or may dry out in a drought. Birds feast
from
above, gophers from below, and slugs from both above and below. A light
planting mix can be sprinkled a bit more heavily over seeds than can
regular
heavy clay garden soil, and still not impede plant growth.
In general, seed flats should end up
with an even surface, without mounds, ridges, or furrows, because watering will
tend to wash soil from high points to low points. Seeds planted at the bottom
of a furrow that is too deep will tend to get covered with more soil, if, when
they are initially covered with the correct amount, the soil doesn’t reach the
top of the furrow. Seeds planted too shallowly, with extra soil piled on top of
them, will tend to be exposed as water begins to level the soil surface. The
same principles apply to outside beds, although a mound method has been used in
certain conditions for some heat-loving large-seeded crops like beans, corn,
squash, cucumbers, and melons (in areas where soils may be too cool and soggy
to allow optimal germination), and a sunken method (like that used by the Hopis
or by the Zunis in their “waffle gardens”) has been used for some of those same
crops where lack of moisture is an issue.
Many of these factors are discussed
in the Beetless’ DO YOU WANT TO KNOW THE SEED DEPTH? Other Beetless’ lyrics
which refer to seed-sowing include YOU WON'T SEED ME (which advocates collecting
and sowing seeds even of those plants that seem to come up well on their own in
the garden) and, from the “Beetless Bootleg” APPENDIX, I SHOULD HAVE SOWN
BETTER (“a belabored, self-castigating number about why seeds might not have
sprouted as desired: planted too deep, too shallow, too thick, too thin, or
from stock that had never matured, was poorly stored, was too old, was
genetically inferior, of the wrong variety, of the wrong species, or a bad
choice to begin with…[d]owner lyrics we don't miss”) and I'M SOW-TIRED (about
what happens when one overdoes a good thing).
John Jeavons’ How to Grow More Vegetables lists temperature ranges and optimal
soil temperatures for vegetable seed germination, and many sources list typical
number of days until seed emergence (which can be affected by soil
temperature). Seeds need favorable conditions to germinate, including adequate
light, air, and water. Seed flats and seed beds need to be kept moist,
especially during that critical period when the seed’s radical (incipient root)
is emerging and establishing itself. In some cases, however, too much water can
be as bad as not enough: those same large seeds that are especially prone to
perish in waterlogged soils or in soils cooled excessively by watering (like
beans, corn, and squash) are watered infrequently until emergence. For
more details, see the Irrigation section.
(forward to Pt. 3) (back to Gardening Guide index)