Water-Wise Gardening Year-Round
Early Spring: The Easiest Unwatered Garden
West of the Cascades, most crops started in February and March
require no special handling when irrigation is scarce. These include
peas, early lettuce, radishes, kohlrabi, early broccoli, and so
forth. However, some of these vegetables are harvested as late as
June, so to reduce their need for irrigation, space them wider than
usual. Spring vegetables also will exhaust most of the moisture from
the soil before maturing, making succession planting impossible
without first irrigating heavily. Early spring plantings are best
allocated one of two places in the garden plan: either in that part
of the garden that will be fully irrigated all summer or in a part
of a big garden that can affordably remain bare during the summer
and be used in October for receiving transplants of overwintering
crops. The garden plan and discussion in Chapter 6 illustrate these
ideas in detail.
Later in Spring: Sprouting Seeds Without Watering
For the first years that I experimented with dry gardening I went
overboard and attempted to grow food as though I had no running
water at all. The greatest difficulty caused by this self-imposed
handicap was sowing small-seeded species after the season warmed up.
Sprouting what we in the seed business call "big seed"--corn, beans,
peas, squash, cucumber, and melon--is relatively easy without
irrigation because these crops are planted deeply, where soil
moisture still resides long after the surface has dried out. And
even if it is so late in the season that the surface has become very
dry, a wide, shallow ditch made with a shovel will expose moist soil
several inches down. A furrow can be cut in the bottom of that damp
"valley" and big seeds germinated with little or no watering.
Tillage breaks capillary connections until the fluffy soil
resettles. This interruption is useful for preventing moisture loss
in summer, but the same phenomenon makes the surface dry out in a
flash. In recently tilled earth, successfully sprouting small seeds
in warm weather is dicey without frequent watering.
With a bit of forethought, the water-wise gardener can easily
reestablish capillarity below sprouting seeds so that moisture held
deeper in the soil rises to replace that lost from surface layers,
reducing or eliminating the need for watering. The principle here
can be easily demonstrated. In fact, there probably isn't any
gardener who has not seen the phenomenon at work without realizing
it. Every gardener has tilled the soil, gone out the next morning,
and noticed that his or her compacted footprints were moist while
the rest of the earth was dry and fluffy. Foot pressure restored
capillarity, and during the night, fresh moisture replaced what had
evaporated.
This simple technique helps start everything except carrots and
parsnips (which must have completely loose soil to develop
correctly). All the gardener must do is intentionally compress the
soil below the seeds and then cover the seeds with a mulch of loose,
dry soil. Sprouting seeds then rest atop damp soil exactly they lie
on a damp blotter in a germination laboratory's covered petri dish.
This dampness will not disappear before the sprouting seedling has
propelled a root several inches farther down and is putting a leaf
into the sunlight.
I've used several techniques to reestablish capillarity after
tilling. There's a wise old plastic push planter in my garage that
first compacts the tilled earth with its front wheel, cuts a furrow,
drops the seed, and then with its drag chain pulls loose soil over
the furrow. I've also pulled one wheel of a garden cart or pushed a
lightly loaded wheelbarrow down the row to press down a wheel track,
sprinkled seed on that compacted furrow, and then pulled loose soil
over it.
Handmade Footprints
Sometimes I sow large brassicas and cucurbits in clumps above a
fertilized, double-dug spot. First, in a space about 18 inches
square, I deeply dig in complete organic fertilizer. Then with my
fist I punch down a depression in the center of the fluffed-up
mound. Sometimes my fist goes in so easily that I have to replace a
little more soil and punch it down some more. The purpose is not to
make rammed earth or cement, but only to reestablish capillarity by
having firm soil under a shallow, fist-sized depression. Then a
pinch of seed is sprinkled atop this depression and covered with
fine earth. Even if several hot sunny days follow I get good
germination without watering. This same technique works excellently
on hills of squash, melon and cucumber as well, though these
large-seeded species must be planted quite a bit deeper.
Summer: How to Fluid Drill Seeds
Soaking seeds before sowing is another water-wise technique,
especially useful later in the season. At bedtime, place the seeds
in a half-pint mason jar, cover with a square of plastic window
screen held on with a strong rubber band, soak the seeds overnight,
and then drain them first thing in the morning. Gently rinse the
seeds with cool water two or three times daily until the root tips
begin to emerge. As soon as this sign appears, the seed must be
sown, because the newly emerging roots become increasingly subject
to breaking off as they develop and soon form tangled masses.
Presprouted seeds may be gently blended into some crumbly, moist
soil and this mixture gently sprinkled into a furrow and covered. If
the sprouts are particularly delicate or, as with carrots, you want
a very uniform stand, disperse the seeds in a starch gelatin and
imitate what commercial vegetable growers call fluid drilling.
Heat one pint of water to the boiling point. Dissolve in 2 to 3
tablespoons of ordinary cornstarch. Place the mixture in the
refrigerator to cool. Soon the liquid will become a soupy gel.
Gently mix this cool starch gel with the sprouting seeds, making
sure the seeds are uniformly blended. Pour the mixture into a
1-quart plastic zipper bag and, scissors in hand, go out to the
garden. After a furrow--with capillarity restored--has been
prepared, cut a small hole in one lower corner of the plastic bag.
The hole size should be under 1/4 inch in diameter. Walk quickly
down the row, dribbling a mixture of gel and seeds into the furrow.
Then cover. You may have to experiment a few times with cooled gel
minus seeds until you divine the proper hole size, walking speed and
amount of gel needed per length of furrow. Not only will presprouted
seeds come up days sooner, and not only will the root be penetrating
moist soil long before the shoot emerges, but the stand of seedlings
will be very uniformly spaced and easier to thin. After fluid
drilling a few times you'll realize that one needs quite a bit less
seed per length of row than you previously thought.
Establishing the Fall and Winter Garden
West of the Cascades, germinating fall and winter crops in the heat
of summer is always difficult. Even when the entire garden is well
watered, midsummer sowings require daily attention and frequent
sprinkling; however, once they have germinated, keeping little
seedlings growing in an irrigated garden usually requires no more
water than the rest of the garden gets. But once hot weather comes,
establishing small seeds in the dry garden seems next to impossible
without regular watering. Should a lucky, perfectly timed, and
unusually heavy summer rainfall sprout your seeds, they still would
not grow well because the next few inches of soil would at best be
only slightly moist.
A related problem many backyard gardeners have with establishing the
winter and overwintered garden is finding enough space for both the
summer and winter crops. The nursery bed solves both these problems.
Instead of trying to irrigate the entire area that will eventually
be occupied by a winter or overwintered crop at maturity, the
seedlings are first grown in irrigated nurseries for transplanting
in autumn after the rains come back. Were I desperately short of
water I'd locate my nursery where it got only morning sun and sow a
week or 10 days earlier to compensate for the slower growth.
Vegetables to Start in a Nursery Bed
Variety Sowing date Transplanting date
Fall/winter lettuce mid-August early October
Leeks early April July
Overwintered onions early-mid August December/January
Spring cabbage mid-late August November/December
Spring cauliflower mid-August October/November 1st
Winter scallions mid-July mid-October
Seedlings in pots and trays are hard to keep moist and require daily
tending. Fortunately, growing transplants in little pots is not
necessary because in autumn, when they'll be set out, humidity is
high, temperatures are cool, the sun is weak, and transpiration
losses are minimal, so seedling transplants will tolerate
considerable root loss. My nursery is sown in rows about 8 inches
apart across a raised bed and thinned gradually to prevent crowding,
because crowded seedlings are hard to dig out without damage. When
the prediction of a few days of cloudy weather encourages
transplanting, the seedlings are lifted with a large, sharp knife.
If the fall rains are late and/or the crowded seedlings are getting
leggy, a relatively small amount of irrigation will moisten the
planting areas. Another light watering at transplanting time will
almost certainly establish the seedlings quite successfully. And,
finding room for these crops ceases to be a problem because fall
transplants can be set out as a succession crop following hot
weather vegetables such as squash, melons, cucumbers, tomatoes,
potatoes, and beans.
Vegetables that must be heavily irrigated
(These crops are not suitable for dry gardens.)
Bulb Onions (for fall harvest)
Celeriac
Celery
Chinese cabbage
Lettuce (summer and fall)
Radishes (summer and fall)
Scallions (for summer harvest)
Spinach (summer)