Gardening Without Irrigation: or without much, anyway

ts to Need L

of soil at field capacity. Except on clayey soils in extraordinarily frosty, high-elevation l

face fluffed up with a rotary tiller or hoe during April and May, to break its capillary connection with deeper soil and accelerate the formation of a dry dust mulch. Usu

Bigger Ro

t hasn't been desiccated by other competing roots. Eliminating any obstacles to rapid growth of

between soil particles. Many other soil-dwelling life forms from bacteria to moles compete for this same oxygen. Consequently, soil oxygen levels are lower than in the atmosphere. A slow exchange of gases does occur between soil air and free atmosphere, but d

gation or where rain falls frequently, it is quite possible to have satisfactory growth when only the surface 6 or 7 inches of soil facilitates root development. When gardening w

otential Roo

or 3 feet down. In soil free of stones, using an auger is more instructive than using a conventional posthole digger or shoveling out a small pit, because where soil is loose, the hole deepens rapidly. Where any layer is even slightly compacted, one turns and tur

d valleys like the Willamette or Skagit can be over 20 feet deep, and hold far more water than the deepest roots could draw or capillary flow could raise during an entire gro

itting an impermeable obstacle such as rock or gravel, not much water storage can occur and the only use this book will hold for you is to guide your move to a more likely gardening location or encourage the house hun

ating

unction as such a barrier. Though moisture will still rise slowly by capillarity and recharge soil above plowpan, plants obtain much more water by rooting into unoccupied, damp soil. Soils close to riv

7-inch-deep slice of soil over, the sole-the part supporting the plow's weight-presses heavily on the earth about 7 inches below the surface. With each subsequent plowing the plow sole rides at the same 7-inch depth and an even more compacted layer develops. Once formed plowpan pre

930s, the field produced small grains. After wheat became unprofitable, probably because of changing market conditions and soil exhaustion, the field became an unplowed pasture. Then in the 1970s it grew daffodil bulbs, occasioning more plowing

ing, either tool can fairly easily be wiggled 12 inches into the earth and small bites of plowpan loosened. Once this laborious chore is accompli

Claye

troyed by weak soil acids and clay is formed from the breakdown products. Then heavy winter rainfall transports these minuscule clay particles deeper into the earth, where they concentrate. It is n

I'd hire him to fracture my land 3 or 4 feet deep. Painstakingly double or even triple digging will also loosen this layer. Another possible strategy for a smaller garden wou

omes more accessible to root growth. Fortunately, once root development increases at greater depths, the organic matter content and accessibility of this cla

dinarily large quantities of organic matter can turn the top few inches into something that behaves a little like loam, it is quite impractical to

des foothills and appear in other places throughout the maritime Northwest, a deep, friable, red clay soil called (in Oregon) Jori often forms. Jori clays can be 6 to 8 feet deep and are sufficient

g a Lik

e small, dull-tasting fruit, there is not much available soil moisture. Where they grow 6 feet tall and the berries are sweet and good sized, there is deep, open soi

in the vicinity of Yelm, Washington. Were they due to extreme soil infertility? Then I learned that conifer trees respond more to summertime soil mois

maritime Northwest have been named and categorized by texture, depth, and ability to provide available moisture. The maps are precise and detailed enough to approximately locate a city or suburban lot.

to Increase

d cooperation known as good tilth. Humus is a spongy substance capable of holding several times more available moisture than clay. There are also new synthetic, long-lasting soil amendments that hold

s into the top 6 or 7 inches of soil. Rigorous double digging by actually trenching out 12 inches and then spading up the next foot theoretically allows one to mix in significant amounts of organic matter to nearly

soil were amended to 10 percent down to 2 feet. If that soil contained little clay, its water-holding ability in the top 2 feet could be doubled. Referring to the chart "Available Moisture" in Chapter 2, we see that sandy soil can release up to 1 inch of

s amendment would increase that to 3 1/2 inches in the top foot or two, relatively not as much benefit as in sandy

enough well-finished compost to cover the garden several inches deep (what it takes to lift humus levels to 10 percent) is enough of a job. Double digging just as much more into the second foot

bsoil Open wit

hat I am aware of will effectively penetrate firm plowpan or other resistant physical obstacles. Such a barrier forces all plants to root almost exclusively in the topsoil. However, once the s

arming books) will grow down 4 or more feet while leaving a massive amount of decaying organic matter in the subsoil after the sod is tilled in. Sweet clover, a biennial legume that sprouts one spring then winters over to bloom the next summer, may g

an be had quite inexpensively at many farm supply stores. Sweet clover is not currently grown by our region's farmers and so can only be found by mail from Johnny's Selected Seeds (see Chapter 5 for their address). Poppy seed used for cooking will often sprout. Sown densely in October, it forms a thick

softened the earth, I spread 50 pounds of agricultural lime per 1,000 square feet and break the thick pasture sod covering next year's garden plot by shallow rotary tilling. Early the next spring I broadcast a concoction I call "complete organic fertilizer" (see Growing Vegetables West of the Cascades or the Te

t a new garden on another plot and replant the old garden to green manures. I never remove vegetation during the long rebuilding under green manures, but merely mow it once or twice a year and allow the organic

ears and then switching to the back yard. Having lots of space, as I do now, I keep three or four garde

lc

fire way to drought-proof gardens while eliminating virtually any need for tillage, weeding, and fertilizing. I have attempted the method in both Southern California a

porated from the soil's surface. If frequent light sprinkling keeps the surface perpetually moist, subsoil moisture loss can occur all summer, so unmulched soil could eventually become desiccated many feet deep. However, capillary movement only happens when so

until the top inch or two of earth is dry and powdery. This effort will probably be necessary in any case, because weeds will germinate prolifically until the surface layer is sufficiently desiccated. On th

ter than bare earth because under mulch the soil stays damp right to the surface. However, dig down 4 to 6 inches under a dust mulch and the earth is jus

gardening becomes very difficult. Laying down a fairly thin mulch in June after the soil has warmed up well, raking up what remains of the mulch early the next spring, and composting it prevents destructive insect population levels from developing while simultaneously reducing surface compaction by winter rai

tely desiccated, no root activity will occur there and the plants are forced to feed deeper, in soil far less fertile. Keeping the topsoil damp does greatly improve the growth of some shallow-feeding species such as lettuce and radishes. But with our climate's cool nights, most vegetables need the soil as warm as possible, an

dbr

en grow in winter by increasing temperature. Many other garden books discuss windbreaks, and I conclude that I have a better use for the small amount of words my publ

ertigating and

, manures, and potent composts mainly improve the topsoil. But the water-wise gar

to limit or prevent midsummer stunting. First, before sowing or transplanting large species like tomato, squash or big brassicas, dig out a small pit about 12 inches deep and below that

weekly or even more frequently. To efficiently spray a garden larger than a few hundred square feet, I suggest buying an industrial-grade, 3-gallon backpack sprayer with a side-handle pump. Approximate cost as of this writing was $80. The store that sells it (probably a farm supply store) will also support you with a complete assortment of

oil Fertilit

e? Most people would say this s

al when soil is fertilized than when it is not fertilized. One experiment required 1,100 pounds of water to grow 1 pound of dry matter on infertile soil, but only 575 pounds of water

es the water cost of every p

ications. And the cabbage family coats its leaf surfaces with a waxy, moisture-retentive sealant that makes sprays bead up and run off rather than stick and be absorbed. Mixing foliar feed solutions with a little spread

cant quantities of phosphorus or calcium into solution using any combination of fish emulsion and seaweed or liquid kelp. The mos

ne thing fertilizer makers find expensive to accomplish is concocting a mixture of soluble nutrients that also contains calcium, a vital plant food. If you dissolve calcium nitrate into a solution containing other soluble plant nutrients, many of them will precipitate out because few calcium compounds are soluble. Even Rapid-Gro doesn't attempt to supp

ables

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Eggplant

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Peppers

ue periodically through early September. I use six or seven plastic 5-gallon "drip system" buckets, (see below) set one by each plant, and fill them all with a hose e

he stem of a plant. It is then filled with liquid fertilizer solution. It takes 5 to 10 minutes for 5 gallons to pass through a small opening, and because of the slow flow rate, water penetrates deeply into the subsoil without wetting much

st/manure tea. Determining the correct strength to make compost tea is a matter of trial and error. I usually rely on weak Rapid-Gro mixed