In humid climates like ours, sandy soils may seem very open and friable on the surface but frequently hold some unpleasant subsoil surprises. Over geologic time spans, mineral grains are slowly destroyed 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 not unusual to find a sandy topsoil underlaid with a dense, cement-like, clayey sand subsoil extending down several feet. If very impervious, a thick, dense deposition like this may be called hardpan.
The spading fork cannot cure this condition as simply as it can eliminate thin plowpan. Here is one situation where, if I had a neighbor with a large tractor and subsoil plow, 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 would be to rent a gasoline-powered posthole auger, spread manure or compost an inch or two thick, and then bore numerous, almost adjoining holes 4 feet deep all over the garden.
Clayey subsoil can supply surprisingly larger amounts of moisture than the granular sandy surface might imply, but only if the earth is opened deeply and becomes more accessible to root growth. Fortunately, once root development increases at greater depths, the organic matter content and accessibility of this clayey layer can be maintained through intelligent green manuring, postponing for years the need to subsoil again. Green manuring is discussed in detail shortly.
Other sites may have gooey, very fine clay topsoils, almost inevitably with gooey, very fine clay subsoils as well. Though incorporation of extraordinarily large quantities of organic matter can turn the top few inches into something that behaves a little like loam, it is quite impractical to work in humus to a depth of 4 or 5 feet. Root development will still be limited to the surface layer. Very fine clays don't make likely dry gardens.
Not all clay soils are "fine clay soils," totally compacted and airless. For example, on the gentler slopes of the geologic old Cascades, those 50-million-year-old black basalts that form the Cascades 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 sufficiently porous and well drained to have been used for highly productive orchard crops. Water-wise gardeners can do wonders with Joris and other similar soils, though clays never grow the best root crops.
Observing the condition of wild plants can reveal a good site to garden without much irrigation. Where Himalaya or Evergreen blackberries grow 2 feet tall and produce 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 soil. When the berry vines are 8 or more feet tall and the fruits are especially huge, usually there is both deep, loose soil and a higher than usual amount of fertility.
Other native vegetation can also reveal a lot about soil moisture reserves. For years I wondered at the short leaders and sad appearance of Douglas fir in the vicinity of Yelm, Washington. Were they due to extreme soil infertility? Then I learned that conifer trees respond more to summertime soil moisture than to fertility. I obtained a soil survey of Thurston County and discovered that much of that area was very sandy with gravelly subsoil. Eureka!
The Soil Conservation Service (SCS), a U.S. Government agency, has probably put a soil auger into your very land or a plot close by. Its tests have been correlated and mapped; the soils underlying the 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. In 1987, when I was in the market for a new homestead, I first went to my county SCS office, mapped out locations where the soil was suitable, and then went hunting. Most counties have their own office.
Maintaining topsoil humus content in the 4 to 5 percent range is vital to plant health, vital to growing more nutritious food, and essential to bringing the soil into that state of easy workability and 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 and release even more moisture than humus. Garden books frequently recommend tilling in extraordinarily large amounts of organic matter to increase a soil's water-holding capacity in the top few inches.
Humus can improve many aspects of soil but will not reduce a garden's overall need for irrigation, because it is simply not practical to maintain sufficient humus deeply enough. Rotary tilling only blends amendments 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 24 inches. But plants can use water from far deeper than that. Let's realistically consider how much soil moisture reserves might be increased by double digging and incorporating large quantities of organic matter.
A healthy topsoil organic matter level in our climate is about 4 percent. This rapidly declines to less than 0.5 percent in the subsoil. Suppose inches-thick layers of compost were spread and, by double digging, the organic matter content of a very sandy 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 water per foot. By dint of massive amendment we might add 1 inch of available moisture per foot of soil to the reserve. That's 2 extra inches of water, enough to increase the time an ordinary garden can last between heavy irrigations by a week or 10 days.
If the soil in question were a silty clay, it would naturally make 2 1/2 inches available per foot. A massive humus amendment would increase that to 3 1/2 inches in the top foot or two, relatively not as much benefit as in sandy soil. And I seriously doubt that many gardeners would be willing to thoroughly double dig to an honest 24 inches.
Trying to maintain organic matter levels above 10 percent is an almost self-defeating process. The higher the humus level gets, the more rapidly organic matter tends to decay. Finding or making 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 is even more effort. But having to repeat that chore every year or two becomes downright discouraging. No, either your soil naturally holds enough moisture to permit dry gardening, or it doesn't.
When roots decay, fresh organic matter and large, long-lasting passageways can be left deep in the soil, allowing easier air movement and facilitating entry of other roots. But no cover crop that 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 subsoil has been mechanically fractured the first time, and if recompaction is avoided by shunning heavy tractors and other machinery, green manure crops can maintain the openness of the subsoil.
To accomplish this, correct green manure species selection is essential. Lawn grasses tend to be shallow rooting, while most regionally adapted pasture grasses can reach down about 3 feet at best. However, orchard grass (called coltsfoot in English farming 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 go down 8 feet. Red clover, a perennial species, may thickly invade the top 5 feet. Other useful subsoil busters include densely sown Umbelliferae such as carrots, parsley, and parsnip. The chicory family also makes very large and penetrating taproots.
Though seed for wild chicory is hard to obtain, cheap varieties of endive (a semicivilized relative) are easily available. And several pounds of your own excellent parsley or parsnip seed can be easily produced by letting about 10 row feet of overwintering roots form seed. Orchard grass and red clover can 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 carpet of frilly spring greens underlaid with countless massive taproots that decompose very rapidly if the plants are tilled in in April before flower stalks begin to appear. Beware if using poppies as a green manure crop: be sure to till them in early to avoid trouble with the DEA or other authorities.
For country gardeners, the best rotations include several years of perennial grass-legume-herb mixtures to maintain the openness of the subsoil followed by a few years of vegetables and then back (see Newman Turner's book in more reading). I plan my own garden this way. In October, after a few inches of rain has 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" (seeGrowing Vegetables West of the Cascadesor theTerritorial Seed Company Catalog), till again after the soil dries down a bit, and then use a spading fork to open the subsoil before making a seedbed. The first time around, I had to break the century-old plowpan—forking compacted earth a foot deep is a lot of work. In subsequent rotations it is much much easier.
For a couple of years, vegetables will grow vigorously on this new ground supported only with a complete organic fertilizer. But vegetable gardening makes humus levels decline rapidly. So every few years I start 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 matter content of the soil to redevelop. If there ever were a place where chemical fertilizers might be appropriate around a garden, it would be to affordably enhance the growth of biomass during green manuring.
Were I a serious city vegetable gardener, I'd consider growing vegetables in the front yard for a few years and then switching to the back yard. Having lots of space, as I do now, I keep three or four garden plots available, one in vegetables and the others restoring their organic matter content under grass.
Gardening under a permanent thick mulch of crude organic matter is recommended by Ruth Stout (see the listing for her book in More Reading) and her disciples as a surefire way to drought-proof gardens while eliminating virtually any need for tillage, weeding, and fertilizing. I have attempted the method in both Southern California and western Oregon—with disastrous results in both locations. What follows in this section is addressed to gardeners who have already read glowing reports about mulching.
Permanent mulching with vegetation actually does not reduce summertime moisture loss any better than mulching with dry soil, sometimes called "dust mulching." True, while the surface layer stays moist, water will steadily be wicked up by capillarity and be evaporated 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 soil is damp. Once even a thin layer of soil has become quite dry it almost completely prevents any further movement. West of the Cascades, this happens all by itself in late spring. One hot, sunny day follows another, and soon the earth's surface seems parched.
Unfortunately, by the time a dusty layer forms, quite a bit of soil water may have risen from the depths and been lost. The gardener can significantly reduce spring moisture loss by frequently hoeing weeds 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 the off chance it should rain hard during summer, it is very wise to again hoe a few times to rapidly restore the dust mulch. If hand cultivation seems very hard work, I suggest you learn to sharpen your hoe.
A mulch of dry hay, grass clippings, leaves, and the like will also retard rapid surface evaporation. Gardeners think mulching prevents moisture loss better 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 just as damp as under hay. And, soil moisture studies have proved that overall moisture loss using vegetation mulch slightly exceeds loss under a dust mulch.
West of the Cascades, the question of which method is superior is a bit complex, with pros and cons on both sides. Without a long winter freeze to set populations back, permanent thick mulch quickly breeds so many slugs, earwhigs, and sowbugs that it cannot be maintained for more than one year before vegetable 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 rains and beneficially enhancing the survival and multiplication of earthworms. But a thin mulch also enhances the summer germination of weed seeds without being thick enough to suppress their emergence. And any mulch, even a thin one, makes hoeing virtually impossible, while hand weeding through mulch is tedious.
Mulch has some unqualified pluses in hotter climates. Most of the organic matter in soil and consequently most of the available nitrogen is found in the surface few inches. Levels of other mineral nutrients are usually two or three times as high in the topsoil as well. However, if the surface few inches of soil becomes completely 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, and the cooling effect of mulch can be as much a hindrance as a help. I've tried mulching quite a few species while dry gardening and found little or no improvement in plant growth with most of them. Probably, the enhancement of nutrition compensates for the harm from lowering soil temperature. Fertigation is better all around.
Plants transpire more moisture when the sun shines, when temperatures are high, and when the wind blows; it is just like drying laundry. Windbreaks also help the garden 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 publisher allows me than to repeat this data; Binda Colebrook's [i]Winter Gardening in the Maritime Northwest[i] (Sasquatch Books, 1989) is especially good on this topic.
In our heavily leached region almost no soil is naturally rich, while fertilizers, manures, and potent composts mainly improve the topsoil. But the water-wise gardener must get nutrition down deep, where the soil stays damp through the summer.
If plants with enough remaining elbow room stop growing in summer and begin to appear gnarly, it is just as likely due to lack of nutrition as lack of water. Several things can be done 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 blend in a handful or two of organic fertilizer. Then fill the hole back in. This double-digging process places concentrated fertility mixed 18 to 24 inches below the seeds or seedlings.
Foliar feeding is another water-wise technique that keeps plants growing through the summer. Soluble nutrients sprayed on plant leaves are rapidly taken into the vascular system. Unfortunately, dilute nutrient solutions that won't burn leaves only provoke a strong growth response for 3 to 5 days. Optimally, foliar nutrition must be applied 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 inexpensive nozzles that can vary the rate of emission and the spray pattern. High-quality equipment like this outlasts many, many cheaper and smaller sprayers designed for the consumer market, and replacement parts are also available. Keep in mind that consumer merchandise is designed to be consumed; stuff made for farming is built to last.
Does crop growth equal water use? Most people would say this statement seems likely to be true.
Actually, faster-growing crops use much less soil moisture than slower-growing ones. As early as 1882 it was determined that less water is required to produce a pound of plant material 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 to produce a pound of dry matter on rich land. Perhaps the single most important thing a water-wise gardener can do is to increase the fertility of the soil, especially the subsoil.
Poor plant nutrition increases the water cost of every pound of dry matter produced.
Using foliar fertilizers requires a little caution and forethought. Spinach, beet, and chard leaves seem particularly sensitive to foliars (and even to organic insecticides) and may be damaged by even half-strength applications. 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 spreader/sticker, Safer's Soap, or, if bugs are also a problem, with a liquid organic insecticide like Red Arrow (a pyrethrum-rotenone mix), eliminates surface tension and allows the fertilizer to have an effect on brassicas.
Sadly, in terms of nutrient balance, the poorest foliar sprays are organic. That's because it is nearly impossible to get significant quantities of phosphorus or calcium into solution using any combination of fish emulsion and seaweed or liquid kelp. The most useful possible organic foliar is 1/2 to 1 tablespoon each of fish emulsion and liquid seaweed concentrate per gallon of water.
Foliar spraying and fertigation are two occasions when I am comfortable supplementing my organic fertilizers with water-soluble chemical fertilizers. The best and most expensive brand is Rapid-Gro. Less costly concoctions such as Peters 20-20-20 or the other "Grows," don't provide as complete trace mineral support or use as many sources of nutrition. One 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 supply calcium. Recently I've discovered better-quality hydroponic nutrient solutions that do use chemicals that provide soluble calcium. These also make excellent foliar sprays. Brands of hydroponic nutrient solutions seem to appear and vanish rapidly. I've had great luck with Dyna-Gro 7-9-5. All these chemicals are mixed at about 1 tablespoon per gallon.
Like foliarsAsparagus Carrots Melons SquashBeans Cauliflower Peas TomatoesBroccoli Brussels sprouts CucumbersCabbage Eggplant RadishesKale Rutabagas Potatoes
Don't like foliarsBeets Leeks Onions SpinachChard Lettuce Peppers
Like fertigationBrussels sprouts Kale Savoy cabbageCucumbers Melons SquashEggplant Peppers Tomatoes
Fertigation every two to four weeks is the best technique for maximizing yield while minimizing water use. I usually make my first fertigation late in June and continue 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 each time I work in the garden. Doing 12 or 14 plants each time I'm in the garden, it takes no special effort to rotate through them all more or less every three weeks.
To make a drip bucket, drill a 3/16-inch hole through the side of a 4-to-6-gallon plastic bucket about 1/4-inch up from the bottom, or in the bottom at the edge. The empty bucket is placed so that the fertilized water drains out close to the 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 of the surface. Each fertigation makes the plant grow very rapidly for two to three weeks, more I suspect as a result of improved nutrition than from added moisture. Exactly how and when to fertigate each species is explained in Chapter 5.
Organic gardeners may fertigate with combinations of fish emulsion and seaweed at the same dilution used for foliar spraying, or with compost/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 at half the recommended dilution. The strength of the fertilizer you need depends on how much and deeply you placed nutrition in the subsoil.
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.
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.
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.
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.
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 BedVariety Sowing date Transplanting dateFall/winter lettuce mid-August early OctoberLeeks early April JulyOverwintered onions early-mid August December/JanuarySpring cabbage mid-late August November/DecemberSpring cauliflower mid-August October/November 1stWinter 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)CeleriacCeleryChinese cabbageLettuce (summer and fall)Radishes (summer and fall)Scallions (for summer harvest)Spinach (summer)
As recently as the 1930s, most American country folk still did not have running water. With water being hand-pumped and carried in buckets, and precious, their vegetable gardens had to be grown with a minimum of irrigation. In the otherwise well-watered East, one could routinely expect several consecutive weeks every summer without rain. In some drought years a hot, rainless month or longer could go by. So vegetable varieties were bred to grow through dry spells without loss, and traditional American vegetable gardens were designed to help them do so.
I began gardening in the early 1970s, just as the raised-bed method was being popularized. The latest books and magazine articles all agreed that raising vegetables in widely separated single rows was a foolish imitation of commercial farming, that commercial vegetables were arranged that way for ease of mechanical cultivation. Closely planted raised beds requiring hand cultivation were alleged to be far more productive and far more efficient users of irrigation because water wasn't evaporating from bare soil.
I think this is more likely to be the truth: Old-fashioned gardens used low plant densities to survive inevitable spells of rainlessness. Looked at this way, widely separated vegetables in widely separated rows may be considered the more efficient users of water because they consume soil moisture that nature freely puts there. Only after, and if, these reserves are significantly depleted does the gardener have to irrigate. The end result is surprisingly more abundant than a modern gardener educated on intensive, raised-bed propaganda would think.
Finding varieties still adapted to water-wise gardening is becoming difficult. Most American vegetables are now bred for irrigation-dependent California. Like raised-bed gardeners, vegetable farmers have discovered that they can make a bigger profit by growing smaller, quick-maturing plants in high-density spacings. Most modern vegetables have been bred to suit this method. Many new varieties can't forage and have become smaller, more determinate, and faster to mature. Actually, the larger, more sprawling heirloom varieties of the past were not a great deal less productive overall, but only a little later to begin yielding.
Fortunately, enough of the old sorts still exist that a selective and varietally aware home gardener can make do. Since I've become water-wiser, I'm interested in finding and conserving heirlooms that once supported large numbers of healthy Americans in relative self-sufficiency. My earlier book, being a guide to what passes for ordinary vegetable gardening these days, assumed the availability of plenty of water. The varieties I recommended in [i]Growing Vegetables West of the Cascades[i] were largely modern ones, and the seed companies I praised most highly focused on top-quality commercial varieties. But, looking at gardening through the filter of limited irrigation, other, less modern varieties are often far better adapted and other seed companies sometimes more likely sources.
Abundant Life See Foundation: P.O. Box 772, Port Townsend, WA 98368(ABL)
Johnny's Selected Seeds: Foss Hill Road, Albion, Maine 04910(JSS)
Peace Seeds: 2345 SE Thompson Street, Corvallis, OR 97333(PEA)
Ronninger's Seed Potatoes: P.O. Box 1838, Orting, WA 98360(RSP)
Stokes Seeds Inc. Box 548, Buffalo, NY 14240(STK)
Territorial Seed Company: P.O. Box 20, Cottage Grove, OR 97424(TSC)
*Throughout the growing directions that follow in this chapter, the reader will be referred to a specific company only for varieties that are not widely available.
I have again come to appreciate the older style of vegetable—sprawling, large framed, later maturing, longer yielding, vigorously rooting. However, many of these old-timers have not seen the attentions of a professional plant breeder for many years and throw a fair percentage of bizarre, misshapen, nonproductive plants. These "off types" can be compensated for by growing a somewhat larger garden and allowing for some waste. Dr. Alan Kapuler, who runs Peace Seeds, has brilliantly pointed out to me why heirloom varieties are likely to be more nutritious. Propagated by centuries of isolated homesteaders, heirlooms that survived did so because these superior varieties helped the gardeners' better-nourished babies pass through the gauntlet of childhood illnesses.
Reduced plant density is the essence of dry gardening. The recommended spacings in this section are those I have found workable at Elkton, Oregon. My dry garden is generally laid out in single rows, the row centers 4 feet apart. Some larger crops, like potatoes, tomatoes, beans, and cucurbits (squash, cucumbers, and melons) are allocated more elbow room. Those few requiring intensive irrigation are grown on a raised bed, tightly spaced. I cannot prescribe what would be the perfect, most efficient spacing for your garden. Are your temperatures lower than mine and evaporation less? Or is your weather hotter? Does your soil hold more, than less than, or just as much available moisture as mine? Is it as deep and open and moisture retentive?
To help you compare your site with mine, I give you the following data. My homestead is only 25 miles inland and is always several degrees cooler in summer than the Willamette Valley. Washingtonians and British Columbians have cooler days and a greater likelihood of significant summertime rain and so may plant a little closer together. Inland gardeners farther south or in the Willamette Valley may want to spread their plants out a little farther.
Living on 16 acres, I have virtually unlimited space to garden in. The focus of my recent research has been to eliminate irrigation as much as possible while maintaining food quality. Those with thinner soil who are going to depend more on fertigation may plant closer, how close depending on the amount of water available. More irrigation will also give higher per-square-foot yields.
Whatever your combination of conditions, your results can only be determined by trial.I'd suggest you become water-wise by testing a range of spacings.
If you've already been growing an irrigated year-round garden, this book's suggested planting dates may surprise you. And as with spacing, sowing dates must also be wisely adjusted to your location. The planting dates in this chapter are what I follow in my own garden. It is impractical to include specific dates for all the microclimatic areas of the maritime Northwest and for every vegetable species. Readers are asked to make adjustments by understanding their weather relative to mine.
Gardeners to the north of me and at higher elevations should make their spring sowings a week or two later than the dates I use. In the Garden Valley of Roseburg and south along I-5, start spring plantings a week or two earlier. Along the southern Oregon coast and in northern California, start three or four weeks sooner than I do.
Fall comes earlier to the north of me and to higher-elevation gardens; end-of-season growth rates there also slow more profoundly than they do at Elkton. Summers are cooler along the coast; that has the same effect of slowing late-summer growth. Items started after midsummer should be given one or two extra growing weeks by coastal, high-elevation, and northern gardeners. Gardeners to the south should sow their late crops a week or two later than I do; along the south Oregon coast and in northern California, two to four weeks later than I do.
The tender, peppery little leaves make winter salads much more interesting.
Sowing date:I delay sowing until late August or early September so my crowded patch of arugula lasts all winter and doesn't make seed until March. Pregerminated seeds emerge fast and strong. Sprouted in early October, arugula still may reach eating size in midwinter.
Spacing:Thinly seed a row into any vacant niche. The seedlings will be insignificantly small until late summer.
Irrigation:If the seedlings suffer a bit from moisture stress they'll catch up rapidly when the fall rains begin.
Varieties:None.
Heirloom pole beans once climbed over considerable competition while vigorously struggling for water, nutrition, and light. Modern bush varieties tend to have puny root systems.
Sowing date:Mid-April is the usual time on the Umpqua, elsewhere, sow after the danger of frost is over and soil stays over 60[de]F. If the earth is getting dry by this date, soak the seed overnight before sowing and furrow down to moist soil. However, do not cover the seeds more than 2 inches.
Spacing:Twelve to 16 inches apart at final thinning. Allow about 2[f]1/2 to 3 feet on either side of the trellis to avoid root competition from other plants.
Irrigation:If part of the garden is sprinkler irrigated, space beans a little tighter and locate the bean trellis toward the outer reach of the sprinkler's throw. Due to its height, the trellis tends to intercept quite a bit of water and dumps it at the base. You can also use the bucket-drip method and fertigate the beans, giving about 25 gallons per 10 row-feet once or twice during the summer. Pole beans can make a meaningful yield without any irrigation; under severe moisture stress they will survive, but bear little.
Varieties:Any of the pole types seem to do fine. Runner beans seem to prefer cooler locations but are every bit as drought tolerant as ordinary snap beans. My current favorites are Kentucky Wonder White Seeded, Fortrex (TSC, JSS), and Musica (TSC).
The older heirloom dry beans were mostly pole types. They are reasonably productive if allowed to sprawl on the ground without support. Their unirrigated seed yield is lower, but the seed is still plump, tastes great, and sprouts well. Compared to unirrigated Black Coco (TSC), which is my most productive and best-tasting bush cultivar, Kentucky Wonder Brown Seeded (sometimes called Old Homestead) (STK, PEA, ABL) yields about 50 percent more seed and keeps on growing for weeks after Coco has quit. Do not bother to fertigate untrellised pole beans grown for dry seed. With the threat of September moisture always looming over dry bean plots, we need to encourage vines to quit setting and dry down. Peace Seeds and Abundant Life offer long lists of heirloom vining dry bean varieties.
Serious self-sufficiency buffs seeking to produced their own legume supply should also consider the fava, garbanzo bean, and Alaska pea. Many favas can be overwintered: sow in October, sprout on fall rains, grow over the winter, and dry down in June with the soil. Garbanzos are grown like mildly frost-tolerant peas. Alaska peas are the type used for pea soup. They're spring sown and grown like ordinary shelling peas. Avoid overhead irrigation while seeds are drying down.