Garden Smarts

Garden Structures

It is the dream of many gardeners, especially those in northern climates, to have a greenhouse. Unfortunately, for a home gardener, it is almost impossible to justify economically. There is no way it’s going to pay for itself, unless you build the frame from salvaged materials and never heat it. Under those conditions, of course, it is simply a large, aboveground cold frame, or a walk-in cloche.
     The only true greenhouse that is really justifiable on ecological grounds is a solar greenhouse, because it practically heats itself. The production cycle of fossil fuels and electricity is inherently detrimental to the environment; to use them for heating a personal greenhouse is irresponsible when simple design features that capture and store the sun’s heat can make it an ecologically positive structure, a way to lessen your dependence on food grown far away and shipped long distances at great energy cost. Though freestanding greenhouses are technically better, because they get more light, I would nonetheless opt for one that is attached to the south side of the house or garage. By building a solar greenhouse attached to your own house, you’ll not only enjoy the benefits of growing plants and crops; you’ll actually help heat your house. On this basis a greenhouse becomes a great investment both for yourself and for the world.
     For the details of greenhouse design and management see: (link). Suffice it to say that you could easily grow enough seedlings for an average-sized home garden in a little 6X8-foot greenhouse attached to the house, say, outside a set of patio doors. For a larger garden, or if you want to grow food in it, an 824-four-foot greenhouse is a very good size; it is an efficient shape, and fits in well architecturally with most houses. You’ll find references in the Bibliography to some excellent books on the subject.
     A cold frame, however, is within the reach of almost every gardener’s budget. In fact, you can often build a respectable one for nothing more than the cost of your time. Old storm windows, some leftover lumber, and a course (layer) or two of cinder blocks will make a really first-rate, permanent frame. For temporary use, even simpler materials will suffice, like a rectangle of hay bales with an old window laid on top.
My grandfather’s cold frame was a three-sided cinder block affair partly sunk into the ground with a deep berm of soil insulating the walls. The covering was multipanes of single-glazed fixed windows of the type used for barns
     He made the front wall two blocks high, but flush with the existing ground level, while the back wall was four blocks high, so that the pitch of the sash from back to front was steep enough to provide for runoff.
     While the materials have changed since my grandfather’s time—rigid insulating acrylic panels, which have a much stronger insulating effect than glass, come in wider sheets, and are almost impossible to break are an improvement as well as a replacement for the old glass sash—the principles of construction are still good. Placement of the cold frame should take into account not only the orientation of the garden—since obviously it should face south, or at least nearly so in the North—but it should also be in a convenient location. Line the outside of the block walls with landscape fabric to keep weed roots in the rear wall berm from working their way through; foam insulation outside the liner will turn the cement blocks into an effective solar heat storage mass. For even more thermal mass, drums filled with water and painted black could be placed inside the cold frame. With these additions, the gardener will have nearly a year-round gardening frame, even where winter temperatures regularly drop below zero.
     One other major structure you’ll want in your garden is a shed for storage of tools, and to work in when the weather is uncooperative. Traditionally, the potting shed is to the gardener what the workshop is to the woodworker, and while the gardener generally works at his or her craft outdoors, there is a need for an indoor workspace.
     The requirements of a potting shed are few, and in many situations may be met by using existing buildings; but where construction of a building for the purpose is necessary or desirable, either on its own or in combination with a greenhouse and/or cold frames, a few basic considerations should be taken into account.
     First, since the potting shed is a place to store tools, there should be sufficient space to hang all your hand tools well up off the ground. Simple nails in the wall will suffice, but the more organized you are the more enjoyable your time in the garden will be, and the less of it will be spent cursing a lost tool. In addition to the hand tools, there should be room for any power equipment you own, the tool-cleaning tub of oily sand described in Chapter 3, and any consumable supplies like potting soil, pots, and such. Fertilizers and pest controls, even organic ones, should be kept in a latched cupboard or room to protect curious kids and animals.
     Second, the potting shed should provide enough space for the gardener to sit comfortably at a workbench to do the tasks that can be done indoors. This includes, but is obviously not limited to, the sharpening and oiling of tools, plus the sowing, pricking out, and potting on of seedlings. A well-designed shed need be no larger than, say, six feet by eight feet. It could adjoin another building, whose exterior wall might suffice for hanging tools; then even less space will do. Whatever its size, though, a tool or potting shed does not need to be fancy; we are simply trying to get in out of the weather, not build an edifice that will stand with the pyramids.
     Our last aspect of basic garden design is compost piles. While many gardeners—my grandfather and I included—start out building their piles on any piece of open ground, you should at least consider making a permanent composting area part of the overall garden plan. If you do, take mind of the fact that compost piles need a lot of air. Any combination of materials and methods that expose the pile to the air, while holding it in place, will work well. Well-designed aerobic compost bins can be bought ready-made from several different companies, but the capacity of most of these is only a cubic yard or so. For larger gardens, you’re better off constructing a series of bins, so that multiple piles can be created and matured in succession.
     Suitable materials include metal fencing; wood, including salvaged trucking pallets (portable platforms for moving materials); and concrete blocks. The metal fence should be the inexpensive type that comes in twenty-five-foot rolls “woven” into a grid of rectangles. It is formed into one or more upright circles and held erect by a couple of metal posts. Or a mesh bin could be made from sections of heavy-duty concrete reinforcing steel mesh welded to rectangles of channel iron, which could be fastened vertically at the corners. A bin made from salvaged pallets works the same way, though, and is certainly cheaper. The problem with all of these bin designs, however, is that the sides are of a fixed height, and the materials to be composted will have to be lifted over it. With a bit of creative siting this problem might be overcome, but in most cases a simpler solution is to make the bin so its walls can be built up as the pile itself grows.
One way is to make the retaining walls from cinder blocks laid so the holes are horizontal. They are stacked in the same fashion as for building the coldframe walls, that is, butted at the corners for stability, yet the horizontal orientation of the holes allows air into the pile along the whole wall. Don’t build this wall much higher than three courses, or the outward pressure of the pile might cause it to fall over and you’ll have a mess on your hands. The pile can be heaped considerably higher, though.
     The composting area should be central to the garden, so the distance that materials will need to be transported is minimized. Ideally, the center of the four-square garden design could consist of a small potting shed/greenhouse/cold frame with compost piles arrayed around it under the eaves of a large overhang. This would be the most efficient possible setup.
     Our own garden can serve as an example again. We put the composting area at the uphill end of the garden, and cut into the hill a bit so that the retaining wall used to form the driveway turnaround could serve as the rear wall of the bins. This makes movement of manure and other composting materials from around the property simple: To unload onto the piles we just back the truck into the turnaround and pull the materials from the back of the truck right onto the piles.

Improving Drainage

The ideal garden soil both holds water and lets it drain away. Many gardens, though (mine included), are built upon shallow topsoil with an impervious layer of subsoil below, or at the base of a hill that collects water after every rain. In cases like this it is worth putting some time and energy into providing a way for water to get out of the garden just as we did for cold air.
     In the final analysis, there are really only two ways to dry a soggy soil: raise the garden or lower the water table. Building raised beds, as discussed earlier in this chapter, may be the simplest solution for a small garden—say, up to a thousand square feet. Use whatever materials you have at hand to build retaining walls for the growing beds, then shovel the topsoil from path areas into them, adding whatever amendment (compost, peat moss, rock phosphate, etc.) are necessary along the way. Put down a weed barrier and a thick mulch in the pathway. Try to get the mulch level deep enough so that even in wet weather the surface of the path will be dry; if possible design the paths so that they act as drainage channels to let surface water run off, away from the garden. The retaining walls will probably need to be eight to twelve inches tall; less than that may not solve a serious soggy soil problem.
     We have a plot in our outer garden that is in a slough on the saddle of the hill with a hardpan layer about eighteen inches below the surface. After a heavy rain, the whole slough fills up like a subterranean lake, and though you won’t see standing water on the surface, the soil in that whole section is like soup for weeks afterward. Our first attempt to put a garden in that spot involved waiting three years for a drought that dried it out enough to get in with a tractor-mounted rototiller, chop up the sod, and then form the whole section into a series of high beds.
     Unfortunately, the amount of water we found we had in that spot was enough to fill the paths up to the surface of the beds, at which point it cut gullies across them and made a beeline for the next saddle down the hill. To solve the problem we bulldozed a small pond on that lower level, and dug a two-feet-deep drainage ditch the length of the saddle, passing right through the center of the low spot and then spilling over the uphill bank of the pond. After a rain the outlet pipe runs like someone had turned on a faucet.
     The first step in drainage work is to figure out where the water is coming from, and at what level. Both surface runoff from rain or snowmelt, and subsurface runoff, where water travels horizontally on top of an impenetrable layer of subsoil, can cause problems for your garden.
     Surface water that runs across the garden during rainy weather may look awful but is relatively easy to prevent. Simply put in a diversion ditch on the uphill side of the garden, sloping downhill and off to the side, around the edge of the garden. Make sure the water has someplace good to go: not just off your property and onto someone else’s but into a watercourse, drain, or sewer. A simple diversion ditch can be made with a standard round-bladed shovel. Skim back the sod (if any) along the course to which you want to divert the runoff, and flip it temporarily onto the uphill side. Then deepen the ditch from beginning to end so that it drops at least an inch for every ten feet of length. Mound the soil you remove along the downhill side in a low berm, and, when you’re done, take the sod you removed at the beginning and stored uphill, placing it upright on the top of the berm. Soon the sod will have rooted itself in the berm on the downhill side, firming the berm against erosion and giving you a simple, long-term solution to surface water diversion.
     For really serious subsoil drainage problems you should call in a professional. But if you just want to protect a relatively small area, and you’re willing to do a little heavy work, here’s how. You can rent a trenching machine if you need to dig a long trench, but short trenches can be easily dug with a special Dutch spade that has a long, narrow blade—only about six inches wide and eighteen inches long. When digging with a trenching spade you should take very small slices with each spadeful, working your way backwards up from the outlet at the bottom, so that any water present in the ditch can escape instead of interfering with your digging. Just rough in the trench on the first pass, then get the precise slope as you work your way back down to the outlet; it should have a slope of roughly half an inch for every ten linear feet, so that the water can flow freely within the pipe you’ll install. Once you feel this is to measure, lay a twelve- or sixteen- foot 2X4 on edge in the bottom of the trench to even out the irregularities and set a plumber’s level on it. If the bubble is just touching to outside edge of the second line on the glass, you have the correct pitch.
     Dig down to the full depth you can reach with the spade. Once the trench is finished it should be five or six inches wide at the bottom and at least eighteen inches deep. If the total length of all your trenches combined is less than forty feet you might as well use the standard white drain tile available from the lumberyard. It comes in ten-foot sections, measures four inches in diameter, and is fairly rigid, with one end flared so that the pieces fit together. When laying rigid drain tile (as it is known) put the flared end downhill so it doesn’t collect soil. Be sure to buy a cap for the top of each run to keep soil out, and a grate for the outlet to keep animals from entering. For runs longer than about fifty feet, so called “elephant tile” is better. It is much thinner and less expensive than the rigid drain tile and easier to work with, though it doesn’t withstand crushing as well and thus can’t be used where the pipe must run under a driveway or road.
     You’ll also need some drain fabric, which is a synthetic soil barrier very similar to landscape fabric or weed barrier cloth. For drainage get the eighteen-inch-wide size; you’ll need enough to wrap up the whole length of drain tile. Lay the soil barrier loosely across the top of the trench and either assemble the rigid pipe or unroll the elephant tile along the trench, on top of the cloth. Then wrap the cloth over the pipe or tile, overlapping the excess, and carefully drop the whole assembly into the bottom of the trench where it should fit snugly. Fill the trench back in and you’re done. At its shallowest point under the garden the drainage tile should be at least a foot beneath the surface so that you won’t hit it during spring preparation of the garden.
     You can improve the performance of this kind of drain by adding crushed gravel (1/2-inch is a good size) around the pipe. You’ll need wider drain fabric to completely surround the gravel and the pipe, at least three feet across. Line the trench with the fabric, shovel in about six inches of gravel, lay the pipe, then cover it with another six inches of gravel and cover it by folding the excess fabric carefully over the top. When replacing the soil make sure that no gaps are left in the fabric for soil to work its way down into the gravel and clog it.

Practical Elements of Garden Construction

Whatever its size and shape, your garden site should be as close to the house—particularly the kitchen—as possible. If you live in a densely populated area you’re not likely to have much choice, but even if you’ve got forty acres out front and another forty back of the house, you should still keep the garden close by. It discourages creatures from making midnight raids, and at the same time it encourages you and your family to spend more time in the garden, to step out quickly for that little extra something for the kitchen, whether it be a snippet of fresh rosemary for the lamb chops or handful of zinnias for the vase. If getting to the garden is a chore, your gardening will be a chore as well.
     The inherent planting efficiency of a bed garden can be enhanced if you plan for low maintenance right from the beginning. Consider permanent sides to the beds, using whatever local materials are available. Do not use treated lumber, though, since you will be eating the plants grown in these beds. The manufacture of treated lumber creates pollution problems that you may not see but that you nonetheless support when you choose to purchase it. (The different types of treated wood and their characteristics are discussed in more detail in Chapter 3.) Stone is one of the best materials if you have it available, but brick, concrete, and some naturally rot-resistant woods native to your area would also make good choices.
     Mulch the main access paths with a thick layer of bark, sand, or cinders—whatever is suitable, local, cheap, and environmentally responsible. Some gardeners, like my grandfather, simply plant grass and maintain sod paths. Be forewarned, though, that sod paths will be constantly migrating into the garden and will require regular attention.
     Make the beds modular. That is, even if they are not exactly the same size, try to keep at least one dimension (usually the width) the same. That way, if you want to extend the growing season with movable tunnels that protect the plants from the heat and cold, you’ll be able to use them on more than one bed without having to reconstruct them each time they’re moved.
     Whatever kind of land and climate you have to work with, remember that the kind of garden that will put you in touch with the quiet rhythms of growth is by definition a garden of human, not industrial, scale. I feel a family garden should be small enough so that any of the major garden tasks can be accomplished in a day or less: spring soil preparation; seeding and setting of transplants; fall cleanup. None of these should take more than a single Saturday of pleasant work for the family.
     Our own garden, made permanent after eight years of being shunted around among the leftover corners of our larger trial gardens, is 60 feet by 120 feet. This is much larger than the average, but we have the room and, as long-time homesteaders, we are trying to provide for a larger proportion of our food. Using the laborsaving techniques outlined above, we are able to keep the labor requirement to a minimum.

Garden Design

While the macro and micro climatic factors that affect garden siting are of critical importance, there are three other elements to consider before you finalize a garden design: efficiency, convenience, and—let’s not forget—beauty. The design should fit the site the way a well-made shoe fits the foot. When you sketch out a garden plan at the kitchen table in the winter, it’s easy to let the clean logic of graph paper lull you into thinking in squares, but unless your land is flat as a billiard table, that’s unlikely to be the best, or most beautiful, shape for your garden. The frost hollows, cold, wet swales, and shady parts of the garden aren’t square, yet they have a lot more to do with the success or failure of your garden than any kitchen table conception.
     The traditional layout for kitchen gardens was established many hundreds of years ago. Called the “four-square”design, it is based on the intersection of two major paths within a symmetrical, enclosed area; in the days before irrigation it usually included a central well or spring. Many of the early examples of this traditional layout were monastic gardens, and while there were perhaps religious and symbolic reasons for the creation of this form, over the centuries its inherent efficiency has gained it a place in the secular world as well.
     Vegetables (and fruits and flowers and herbs) were grown in raised beds marked out by the permanent paths. The four equal-sized plots that resulted (often with smaller perimeter beds around the inside of the wall, fence, or hedge that enclosed the garden) made crop rotation and planning easy. The diversity of the plantings not only made balanced demands on the soil, but preserved the natural balance of the garden’s animal life—small mammals, insects, amphibians, and birds—an important factor in keeping pest problems under control.
     In Europe this style became highly refined; some of the formal “potagers” of the nobility were eight acres or more in size, often completely surrounded by a high stone or brick wall against which tender fruits and vegetables could be grown far north of their normal range. The plantings in these gardens were quite formal, with boxwood edging the beds, and arbors at the intersection of the secondary paths trellised with espaliered fruit.
     American kitchen gardens have, on the whole, been much less formal. From the beginnings of colonization there has been less emphasis on strict training of the plants, but the efficiency and utility of the classic four-square layout has been largely preserved. Americans have adapted, and should continue to adapt, this traditional design to the particulars of their lives and their land. An old-fashioned garden gracing the yard of a restored Colonial-style village home in the Northeast may stick to the strict four-square design, but gardens on steeply sloped, irregularly shaped lots can be terraced into the slope and follow its contours to make the most of the conditions of the site. Hacienda gardens in the arid Southwest, as well as those nestled next to a cottonwood stream in the Midwestern prairies, can both make the most of the protection from sun and wind offered by adobe walls or tall, windbreak hedges. The basic elements, though—raised growing beds in multiple, equally sized plots, some form of enclosure and proximity to both water, and to the house of the gardener—should remain the same. What changes are merely those details that reflect regional, personal, and site-specific realities: the shape and size of the beds and the specific vegetables and varieties grown in them. Ideally each design should reflect the sensibilities and opinions of the gardener who created it, as adapted to that site.
     I once put in a garden just for fun, a small demonstration garden at our trial fields, designed solely to prove that a vegetable garden could be beautiful. Though it was designed “on the fly” with little thought to efficiency, it still produced a much higher yield than a row garden of the same size, and it looked a lot nicer, too.
     First I marked out a rectangle in the open garden area next to our upper greenhouse that measured twenty by fifty feet and rototilled it, which took a couple of hours. Since the greenhouses were rectangular, and I felt a geometric pattern would look best in that spot, I took stakes and twine and made a large X connecting the opposite corners. The spot where the lines crossed was the center of the plot, and I drove a stake to mark it. Then I went to work on building up the growing beds.
     I lightly shoveled a path underneath the two lines, using a flat-bottomed shovel, then took them down. Next, I stood on the center spot and gave the other end of an eight-foot piece of twine to my (then) seven-year-old daughter Molly, and had her pull it taut. Then she walked around me, making a sixteen-foot-diameter circular path two feet in from the edges of the plot. After that I took in four feet of the twine so it was only four feet long, and had her walk the circle again (which she thought both mysterious and exciting). That gave me a second path four feet in from the first. I then shoveled out those paths, and within a few hours had a funky, formal vegetable garden with a whimsical touch—and it took no more work or trouble than a standard, square-bed design!
     After these basics were set, I neatly raked up the edges of the beds and erected a large post in the center, on which I mounted a sprinkler so I could water the entire garden from that one spot. From the top of the post I ran twine out to the edges of the eight-foot circle and planted pole beans beside each line. Inside the bean teepee, I planted cool weather greens that would benefit from the shade cast by the mature pole beans and made a small sitting area for the kids to have their tea parties. The varied sizes and shapes of beds in this garden provided a real wealth of design and cropping possibilities, along with visual and horticultural diversity.

Garden Siting

The climate of your whole region is the macroclimate, or big picture within which your gardening season exists. But when we talk about the effect of proximity to a lake, or the effect of increased altitude on your season, we are talking about particular smaller deviations from the norm for your region—that is, microclimates. This differentiation continues right down to the neighborhood level. My next-door neighbor, who lives a quarter mile away, down by the stream, always gets lower temperatures than I do because on winter nights cold air flows down the surrounding hills and collects on the valley floor, creating a pool of cooler air. On the hillsides around our valley the temperature may be five to ten degrees warmer.
     In fact, one of the reasons we bought our property is that we thought it would be above the average top of this pool of air in the summer, and thus we would miss the first and last frosts. Unfortunately, the airshed for this valley is larger than I realized. On most of those chancy spring and fall nights enough cold air filters down from above to fill halfway up the side of the valley, including most of our garden. On such a night we’ll have a frost in the lower part, but not in the upper. The microclimate of our farm differs from our neighbor’s, true enough, but not as much as we’d hoped. Meanwhile, other neighbors farther up on the facing side of the valley will sometimes go an extra few weeks without frost!
     By taking these kinds of realities into account you can minimize their negative effects on your garden, and help out whatever good features your microclimate has to offer. Let’s continue to use my own garden as an example. We are on a southwest ridge about fifty to one hundred feet above a small south-facing intervale in a larger mountain valley, at an altitude of 1,200 feet in the southern Green Mountains of Vermont, at about 43.5 degrees north latitude. We are in a cold area, and the aim of our site design was to warm up the garden’s microclimate, as the major problems we face are cold, soggy soil, frost, and wind.
     First, we put our gardens on the southeast face of the ridge. A patch of hillside that slopes to the south receives more direct sunlight (especially in the winter) than land that slopes to the north because the lower the sun gets in the sky, the greater is the difference in the angle at which it strikes the two pieces of ground. In fact, every degree of slope to the south is like moving your garden south to a lower latitude. That alone adds two or three weeks to each end of the gardening season, since the soil warms up faster in the spring and stays warm longer in the fall. Because ours is a southeastern slope, it is also protected a bit from the prevailing northwest wind, and gets sun as early as possible in the morning.
     Keep in mind that, in the South, your needs would be opposite: you’d plant on a northern slope to decrease the power of the sun—in a sense sending your garden north during the hot months. Many experienced southern gardeners actually have two plots: one for fall and winter that is in full sun, sloping to the south; and another tucked into a shady spot on a north slope.
     Second, we put our crops in raised beds, running generally east to west across the slope. Raised beds help the soil to drain better in spring, so it warms up faster, yet their cross-slope orientation helps check erosion. Also, the south side of each bed catches extra sun, accentuating the existing slope of the garden itself, and “moving it” farther south.
     Third, since we are located down within the “frost pool” for this little valley, we have done what we can to help the cold air drain away as quickly as possible. The source of our problem is really at the south end of the intervale, where a neighbor’s pasture has grown back to forest, so that the only way out for cold air that has settled in the valley is down the narrow streambed. What we did was to clear a gap in the trees on the downhill side of our property, and plant a windbreak—or in this case a “frostbreak”—of evergreens just above the garden, to divert the flow of cold air out into the driveway, where it can escape more quickly down into the intervale. The garden also has solid six-foot stockade fencing on the uphill side, while the downhill side uses pickets; that way cold air from above is shunted around the garden while air from the garden itself can filter through the pickets and escape.
     Since our cold winds come from the north and west we continued the solid fence and windbreak around to the west, until we got to the point where the summer sun sets on the solstice, which is its northernmost reach in the sky. That way, our fence doesn’t block the June sun from reaching the main part of the garden, yet it blocks the cool winds that often blow down from the Canadian tundra in early summer. This arrangement has the added benefit of channeling the midsummer breezes that come from the southwest up across the garden, bringing relief from the heat in the dog days of early August.
     In order to get the most from your garden site, take all such things into account. What are the limiting factors on garden productivity in your area: temperature, humidity, available sunlight? Working from a knowledge of what the problems are and what combinations of siting, planting, and construction can do to alter them, you should be able to increase the productivity of your garden plot by increasing the length of the growing season and reducing a lot of the stresses that cause plants to falter.

Geography and Climate

What are those realities? The following is a broad overview of the different climatic regions of North America. Don’t lose sight of the fact, though, that the best information on local climates comes from experienced local gardeners. Get to know your neighbors.
     In the East the determining factors for your garden site are likely to be the latitude, the altitude, and how far you are from the ocean. The Gulf Coast states may be frost-free year-round, and northern Georgia may have a frost-free period of eight months, while in northern Maine or Vermont you’ll be lucky if you get three months of frost-free nights. Being near the ocean will add anywhere from one to four weeks at each end of the season. But every 300 feet or so of elevation will cost you a week at each end. Also, the farther you are from the ocean, the more hot weather you’ll have in summer and cold weather in winter. In general, the farther south you go the more humid the air becomes. But nowhere in the East is water a serious natural problem; rainfall is sufficient for most plants, and evenly distributed throughout the year.
     In the Midwest and Plains regions there is considerably less rain. Near the Great Lakes spring comes late because the winter-cooled water doesn’t warm up as quickly as the surrounding land; the fall, however, is often long and mild as the Lakes have been heated by the long days full of summer sun. So proximity to the Lakes, and the orientation of the garden plot are important. Farther west, where the damping effect of the Lakes isn’t felt, the weather is more erratic, and heat and cold alternate rapidly, regardless of the season. But still, the farther north you are, the shorter the season, and the more pronounced the effects of daylength on your garden. Important factors to Plains gardeners are wind and water, and a garden design needs to take both into account.
     The Rocky Mountain region is generally dry and sunny, but altitude is a crucial factor. Generally, if you are farther to the north and west, your climate is likely to be a bit wetter and cooler. But rainfall at higher elevations can be twice, up to as much as six times, the one inch a month that the intermountain lowlands receive on average each year. The length of the growing season varies considerably, too. In the southern deserts the frost-free period may be a full ten months (though the middle of summer will be too hot for many crops), while the northern Rockies will be lucky to get more than a couple of frost-free months most years. The rule of thumb is that each thousand feet of elevation or 3.5 degrees (250 miles) of latitude will shorten the growing season by a week or two at each end. In addition, the terrain of the mountains favors the development of frost pockets which can further shorten the season.      This, and other local effects, make experience with a particular location all the more important.
     West Coast gardeners need to consider their relationship to the Pacific Ocean, which has an even greater effect on gardening than the Atlantic does on gardeners in the East. Many areas of the Pacific Coast rarely or never see a frost, yet gardeners there have a harder time growing tomatoes than we do here in Vermont. Why? Because of the cool ocean breezes, persistent fog, and long periods of cloudy, wet weather. Inland, over the first range of mountains, though, summers are hot and dry, often without a drop of rain for months on end. Even the winter rains are much less frequent.
     Latitude, longitude, and altitude are all important. In general, the farther north and west you are, the cooler, wetter, and cloudier the weather will be, so the more of that kind of weather you should plan for. In the winter, what is rain at lower elevations becomes snow as you move up into the mountains; in fact, the severity of a Pacific winter storm is often discussed in terms of how far down the mountains it snowed. Local variations—called microclimates—are much more pronounced in the Far West, and so siting is again crucial. For example, the average maximum temperature in July at Half Moon Bay, on the central coast of California, is only 64˚ F (18˚ C), while in Tracy, just fifty miles east (but over the coastal mountains) the average July high is 95˚ F (35˚ C). In Sonoma County, California, alone there are something like twenty-four different climate zones based on the standard indicators of weather statistics. The same effect, though modified by altitude, latitude, and longitude, is true all up and down the coast. Rainfall is also quite different from place to place, but in general you’ll need to have access to water at some time during the growing season. Here in New England we like to say, “If you don’t like the weather, wait five minutes.” On the Pacific Coast, if you don’t like the weather you can drive five miles. Here we have frost pockets, there they have fog pockets.
     These broad climatic regions interact with the regional and local topography to produce a set of average (and extreme) temperature data that can be mapped. The U.S. Department of Agriculture (USDA) has taken this information and produced a set of maps of the country that show the average minimum temperature and the average spring and fall frost dates for any location in the United States. Recently, a similar map was published by the American Horticultural Society that shows the same kind of data in terms of maximum temperatures. This will help gardeners in warm regions of the country plan their gardens to avoid periods of excessively high temperatures, which can be harmful to many vegetable crops.
     For more detailed climatic data, there is an excellent two-volume, 1,185-page compilation called Climates of the States, published by Gale Research from National Oceanic and Atmospheric Administration (NOAA) data. It lists full information for multiple reporting stations in all fifty states, and is available at many public libraries.
     Combined with a knowledge of the general weather pattern, these resources can help you determine the nature of your garden’s climate.

Weather and Climate

I don’t know about you, but every season in my garden—even every heat wave, drought, or rainy, cool month—seems like the hottest, driest, or wettest time I’ve ever seen: an extreme, a record, the final unspringing of nature. Every storm seems to have a wind that is stronger than all that preceded it.
     “It never used to rain like this when I was a kid,” I think, looking out at the downpour that is drowning newly set seedlings. And at the local coffee shop during the annual brief January thaw I always overhear one patron mutter to another, “You know, we don’t really have winters anymore . . . not like we used to, at least.” The reason we fail to see the climate for the storms is that climate is a kind of history; our hindsight in the form of weather records shows that, on the whole, the overall American climate is remarkably constant.
     The climate of expanding cities is certainly changed as old farm fields are paved over for shopping malls and expressways, just as the climate of the Amazon is changing as loggers and ranchers clear-cut the trees. But the new climates that result are themselves relatively stable once established, for good or bad. (This is an excellent argument both for controlling clear-cuts and paving, as well as working to establish greenswards in urban areas.)
     You can prove this to yourself—and gain a lot of knowledge about which plants and varieties grow best in your specific situation—if you keep a garden journal with daily weather notes. Our garden is in the mountains of Vermont, and from our hillside we look southwest from a small intervale out over a mountain valley ringed by ski areas. We’re accustomed to a lot of snow in the winter; in fact we depend on it to help the perennial plants in our vegetable and flower gardens withstand the temperatures of –30˚ F that we can count on almost every winter.
     The year we cleared our land, 1980, was a warm winter. There was no snow, and temperatures during February regularly hit the fifties. We planted our first peas in the new garden during the second week in April. In 1983 we had a snowy winter, and with more than twelve feet overall, including one storm of forty inches in late March that collapsed one of our greenhouses. In my garden journal I find that we planted our peas on April 15. In 1989 we had a temperature of -39˚ F with bare ground, and it froze the soil to a depth of seven feet. During the rest of the winter, Virginia got more snow than we did. But according to my garden journal, we were able to plant our peas on April 15.
     In reality, our miniscule Earth, with its thin covering of air, puny oceans, and little stubbly bumps of mountains that an astronaut can barely make out from orbit is just one small part of a much larger solar system—and the sun itself is just a tiny star among all those we can see. But from our human perspective the Earth is a giant thermal engine with a seasonal momentum that one small snowstorm in the mountains of Vermont is certainly not going to affect. We may be in a ten-year or hundred-year warm spell; we humans may even alter the climate with our profligate energy use. But the new climate that results, and its constituent microclimates, will continue, from then on, until some new climatic trigger comes along to reshuffle the deck.
     While this long-term statistical stability underlies the climate of our gardens, we will continue to see only the temporal effects, the succession of cool or warm, wet or dry seasons. Thus, when siting and designing the garden, we should do what we can to fit it into both our experience of the site and the historical climate realities of our region.

Designing the Garden

The key to intelligent garden siting and design is to understand the geographical factors involved, and then apply them to your own situation. Theory is fascinating stuff, but it doesn’t grow good vegetables because it doesn’t get its hands dirty; it concentrates on the general at the expense of the specific, while gardens are really communities of specifics. So let’s cover a little theory, then consider a few examples drawn from the particulars of my own garden. But please, apply it to your own site and climate.
     The essentials that any garden must have are water, nutrients, and light. From the natural abundance of the fertile, sunlit garden to the contrived cornucopia of hydroponic growing under lights, these three elements are fundamental. They are the basic ingredients with which the plants create themselves as they grow, and so. whether you are starting a new garden, or trying to improve one you have already, these must be the starting points.
     Sunlight not only provides the fuel for plant growth but as the causative factor in the creation of climate and weather, it is the backdrop for nearly every decision in siting a garden. It is the differential heating of Earth’s varies surface by the sun that causes the wind; the rough geography of mountains, valleys, plains, and lakes that makes rain, sleet and snow vary from location to location; the changing daylength, and the angle of sunlight that causes the seasons to differ vary from north to south. Thus, every factor important to the success of a garden is related to climate and geography.