Garden Smarts

Starting A New Garden

The first step in starting any new garden is to get the soil into an easily workable condition. Most vegetable species grow best in a soil that is near neutral in acidity, loose in texture, able to hold significant moisture without becoming soggy, and free of competition from the roots of established trees. Even small rocks and roots should be removed if possible; they are great protectors of weed seedlings: every place the hoe hits a rock and skips during cultivation, a weed is sure to appear.

     Immediately after breaking ground for a new garden you should test the soil. You can buy kits to do this, or buy a soil sample pouch at a garden center and send a sample of your soil to a state laboratory for testing. Within a few weeks the lab will send back a detailed report on the soil’s current nutrient levels, with a recommendation for fertilizers. Unfortunately, most soil labs ignore organic materials and offer their advice solely in terms of chemical fertilizers. If you will be using bagged organic fertilizers, you will find their N-P-K levels printed on the bag. If you will be using “raw materials,” however, you’ll need to know the nutrient content of various organic materials like manure, leaves, blood meal, seaweed, and rock powders.

     Table 4–1 lists N-P-K levels of these materials based on their weight (see page 000). Ideally, they should be composted first, and the compost used for enriching the soil. But this is not always convenient, or even possible. Very bulky materials like hay, straw, seaweed, or leaves can be used as a mulch first, and allowed to break down partial before being turned under to complete their decomposition. Fresh animal manures can be spread and turned under immediately so their nutrients are caught in the soil rather than being lost to the air while the pile waits for other materials to arrive; just don’t plant crops for at least a month so the manure has a chance to break down. Materials like rock phosphate, greensand, wood ash, or blood and bone meals can be added at any time and mixed into the top few inches of the soil. They can also be used to fortify a compost pile.

     To make sure that your test sample represents actual conditions at the plants’ root level, take three or four samples from around the whole garden plot. Don’t take a sample from any place that was recently fertilized or limed; it will distort the results. To get a clean sample from root level, take a shovelful of soil out of the ground and set it aside, then slice another section, only an inch or so thick, from the side of the hole. With a penknife or scrap of wood, scrape away the top inch or so, and take your sample from a one- or two-inch-wide vertical section of what remains. Mix that small bit with the other samples from around the area to be tested; all roots, leaves, rocks, and other material should be removed, and the test sample should be dry and fully pulverized before mailing.

     One of the most critical aspects of a soil test is the pH report, which tells you if your soil is overly acid or alkaline. This is important, because all nutrients are more or less available depending on the pH balance of the soil. On a scale of 0 to14, each whole number represents a tenfold difference from the next whole number. Thus, taking the number 7 as neutral (which it is on the pH scale), a pH of 6 indicates that the soil is ten times as acidic, while a pH of 8 indicates it is ten times as alkaline. The soil report will usually include a recommendation of how much lime (to raise the pH) or sulfur (to lower the pH) should be added, and in what form. Keep in mind: if the pH of your soil is more than two points away from neutral, you should break the application of lime or sulfur into two or more applications to avoid shocking the resident soil life with too radical a change.

     Once an ideal pH of 6.0 to 6.8 (at which the widest range of nutrients is optimally available to most plants) has been established, an ongoing program of manure and compost applications will remove the need for any further attention to soil pH. Except for special conditions, the latest research backs up this belief. Only if your soil is of the most extreme acid or alkaline nature, or your garden is subject to serious acid rain and snowfall, should an ongoing program of pH balancing be necessary.

Plan Ahead If You Can

Ideally, you should pepare your new garden spot a year ahead and cover-crop the area for a season before making it into a garden. Cover cropping means growing a vigorous, thickly sown crop of soil-improving plants to choke out existing (usually undesirable) plants. The principle can be adapted to any region by changing the crops used. Just make sure to keep the ground covered continuously with fast-growing crops so the weed seeds germinate, but don’t have a chance to grow. We cover-cropped our garden one plot at a time until, after four years, the entire garden had been cleansed of weeds and the soil greatly improved. During the first season after cover cropping we’ve found weeding almost entirely unnecessary until midsummer and—if we are diligent about maintenance—minimal thereafter. As an example, here is the plan we used (good for New England):

     Start by rototilling or digging the ground as early in spring as possible and immediately sow annual ryegrass. You don’t need to worry right away about smooth soil, or removing the rocks and roots, though you might as well grab the ones you see. Once the last frost date arrives, turn under the annual ryegrass and immediately plant buckwheat. When the buckwheat starts to flower (in about a month) turn it under, and plant buckwheat again to make sure that the ground is kept covered and weed species don’t have a chance to reestablish themselves. At some point during this first summer do a soil test to determine any gross deficiencies or imbalances in the soil.

     If the first planting is very weak because the soil is totally depleted, you may want to manure the plot early on. If so, do the test first, and keep track (in your garden journal) of how much manure you added. Keep replanting buckwheat until Labor Day, then switch back to annual ryegrass. Before tilling and planting this time, though, remove all the roots and rocks that have come to the surface, and add any soil amendments found to be necessary by the soil test; they work best if they have the winter to break down. In USDA zones 1 through 5, the annual ryegrass will grow quickly in the cool fall weather to prevent any of the original cover from returning, then it will winterkill, leaving a thick mulch of dead foliage on the ground for the winter, protecting it from erosion and preventing regrowth of weeds.

     The following spring you can again rototill, and the garden will then be ready to plant. In USDA Zone 6 and warmer, where the annual ryegrass doesn’t die off during the winter, you’ll need to wait up to three weeks after spring tilling to let it decompose before planting your crops.

     This method works for any size of garden, and can be accomplished with hand tools as well as with a rototiller; just mow the covercrop with a string trimmer or scythe before turning it under. Start in one corner of the plot and work you way across, taking small slices with the full depth of a spading fork. Lift the soil just a bit above the ground, give a quick twist while dropping the fork out from under its load, then raise the tines quickly again, slapping the bottom of the falling soil with the tines. That will break it up nicely. Any clods that remain can be swiped sideways with the slightly offset edge of the fork and pulverized in place. If you come across any rocks in the process (in Vermont we always do!) toss them to the side of the garden or into a wheelbarrow.

     Some cover crops—called green manures—are used to add nutrients to the soil as well as to choke out undesirable plants. This can happen in two ways. One involves turning under young, vigorous growth, instead of waiting until the tissues harden as the crop begins to flower. This young growth breaks down quickly and stimulates the biological activity of organisms in the soil; these then break out and release nutrients contained in the mineral portion of the soil. This is feeding the soil by feeding the community of decomposers—plants and animals that live on decaying organic matter—whose activities increase the fertility of the soil in a qualitative way that no chemical brew can match.

     Then there is the one-quarter of soil volume which is air, itself more than three-quarters nitrogen. The second way that green manures can add nutrients to the soil is by helping capture this soil-bound atmospheric nitrogen. Legumes are plants that have the ability to form a symbiotic relationship with a group of soil bacteria known as rhizobia.Beans and peas are legumes, as are clover, alfalfa, and vetch. The Rhizobium bacteria, of which there are many species specific to particular legumes, live on the roots of the host legume and form small colonies called nodules. They are able to draw nitrogen from the air for their own nourishment and store it in nitrate form, which is just how plants like their nitrogen. By planting a legume crop that has been “inoculated” with the proper strain of Rhizobium and then by turning it under after the nodules have had time to form, the gardener can convert atmospheric nitrogen into nitrates, and do so essentially for free, beyond the cost of seed and inoculant.

In A Hurry?

If it’s already fall when you are ready to establish your new garden, you can get a head start on the following spring by manuring, liming, and then turning over the proposed garden area and covering it with a single large sheet of black plastic; that will keep the soil in total darkness so the weeds can’t come back. Weight down the plastic with rocks and board, to keep the wind from blowing it away. If possible, do a soil test beforehand. If that isn’t possible, spreading five pounds of lime and a few bushels of manure for every hundred square feet is a good rule of thumb for new gardens here in the East. (If you can’t get manure, use bagged organic fertilizer at the labeled rate.) Try to do the preparation early enough in the fall so that the existing plant cover will try to regrow under the plastic and thereby wear itself out; by spring you’ll have bare ground to start with.

     If it’s springtime, and you can’t wait a year’s time—and the spot you’ve chosen is currently in lawn or pasture—you can still clear a spot and make a garden right away. Here’s how: Cut out a strip of sod the length of your proposed garden with a sharp-edged, flat-bladed spade, then work the spade under the edge and roll it back like carpet, taking the thinnest layer possible. I like to do this on my hands and knees, using a dull, broad-bladed field knife to cut loose the roots as I go. That allows me to roll the sod up neatly without it pulling apart. It’s a bit dirtier this way, but it’s also less work.

     Once the sod has been removed, you can use it somewhere else around the place perhaps to patch a spot of lawn or pasture that isn’t doing well; or use it instead of cinder blocks to make the sides of your first compost pile. Just be sure to stack the sod squares with their roots face-up so they won’t take root and start growing again.

     The biggest problem I’ve seen with new gardens cut out of existing sod is that insect pupae (grubs) in the soil will attack the newly sown plants when they awaken; this is not surprising, since you’ve taken away the food source that was there when they went into hibernation, and they wake up hungry. The second big problem is the sprouting of perennial plants from their roots. In one early garden of ours we lost 180 out of 200 tomato transplants to cutworms. Then we had to abandon the rest when they were swamped with witch grass that sprouted from rhizomes we left behind when we prepared the ground.

     So if the spot you’ve chosen for your garden is an old pasture overgrown with perennial grasses, or brush and saplings, be sure to clear out not only the roots and rocks, but every single rhizome, grub, cocoon, and cutworm you see, or the grass and shrubbery will begin sprouting right in the middle of your garden and, once the cutworms get to work, that’s all that will be left. Don’t worry, but do be thorough; you’ll be glad you were.

     Especially if the area is infested with perennial grasses like quack grass or witch grass—and you don’t want to lose a season choking them out with cover crops—you really should sift the top six inches of soil through a piece of 1/2-inch metal screening (hardware cloth) to be sure you’ve gotten all the grass rhizomes; the tiniest shred is a near guarantee of eventual problems. If you put these weeds on your new compost pile, be sure to bury them deep enough, along with manure or other material so that their shoots can’t make it to the surface. I would recommend—no matter how much of a hurry you are in—that you grow a choke-out cover crop on at least a quarter of your garden-to-be; that way you’ve got a start on a good rotation, and if you keep at it you’ll beat your weed problem once and for all within the course of four seasons (to cover all four quarters).

Double Digging

Just about the worst soil condition for establishing a new garden is the compacted subsoil left over from the construction of a new house. If you are present when the excavation is done, make sure that the machine operator puts the topsoil aside and then replaces it after all the other work is done; otherwise you may be left with a surface layer that is actually mineral subsoil, which on its own is entirely unable to support a decent garden. If that happens, you can still establish a fertile, thriving garden, but it will require a lot more work.

     Your best hope if you are starting with any hard, solid soil is the classic method of soil improvement for small gardens, which is commonly known as double digging, or “bastard trenching.” Using this method, you can make virtually any soil productive within the space of one growing season.

     When double digging, it’s important to wait until the soil is moist, but neither very wet nor very dry: that way, you’ll expend the least amount of effort and will do the most good for the soil. This is especially true of clay or “adobe” soils; when dry they are nearly impossible to penetrate, and if you work them while wet, they are goopy, but then dry into brick-hard clods.

     First remove the plant cover, if any, by the sod-moveal method just described, then start at one edge of the proposed plot and, with a spade, dig a trench along one side, about eight inches to a foot deep, and set the soil aside, either on a tarp or in a wheelbarrow. (You’ll need it at the end of the process.) Then loosen the soil in the bottom of the trench with a spading fork by jamming it down into the subsoil and working the handle back and forth in every direction. If you can, physically lift the soil and drop it back into the bottom of the trench to break it apart. With poor soils, especially construction spoil, it helps to add some compost, manure, or other organic matter to the loosened material in the bottom of the trench. Next, remove another strip of the surface soil to widen the trench, break it up, and place it on top of the loosened soil and manure in the bottom of the first strip you’ve dug, without inverting the layers. Then loosen the bottom of the second strip in the same way as the first, and continue the process until you reach the other side of the bed. Take the soil you saved from the very first strip to fill in the last strip of the trench.

     The results of the soil test you did at the beginning will tell you whether to add various amendments to the soil to carry your garden through the first year (while you establish compost piles). When adding a number of different organic amendments, alternate light- and dark-colored materials so you don’t lose track of where you’ve spread what. Almost all soils, regardless of their condition, will benefit from the addition of organic matter, whether in the form of compost (often called the “black gold” of organic gardeners) grass clippings, spoiled hay, rotted leaves, even shredded yard waste or manure. Organic matter helps lighten heavy soils and provides precious water-holding capacity for light ones. If you didn’t have a chance to build up this important constituent of healthy garden soil by cover-cropping and green manuring, you can add it now. Just don’t use fresh manure on ground where you’ll be planting immediately; it needs a minimum of three weeks to break down, and a month or two is better. Ideally, you should compost manure before spreading it on the garden or apply it in the fall before planting your winter cover crop, turn it under, and let it mellow.