Making a new vegetable garden next spring? Do you plan to enlarge an existing one? In either case begin building your garden in September and October. Why? Because it takes months before ordinary dirt becomes rich garden soil. This transformation can happen over the winter, making the soil ready to grow vegetables by spring. But if you wait until spring to begin improving the soil it may take until July before the garden will grow plants well.

First, consider the new garden’s location. A spot getting full sun (9 AM to 6 PM) yields a lot more vegetables than one receiving direct sun only from noon until late afternoon or from 10 AM to 3 PM. A full sun garden may yield as much as three times more than a bright shade garden or one that is deprived of sunlight for part of the day.

More than mere yield, the flavor and nutritional content of vegetables depends on how much direct sunlight the plants get. Fruiting vegetables especially—tomatoes, snap beans or zucchini—require full sun to achieve rich flavor. They’ll be slightly bland if they lose the morning sun; they’ll be bland and small if they miss the afternoon sun.

A gentle sun-facing slope (3–5 degrees of incline to the south) will grow vegetables as though it were located several hundred miles to the south of where it actually is. Similarly, a spot that gently slopes to the north will grow plants as though it were located several hundred miles further from the equator.

Consider drainage as well: if the site is low and gets waterlogged in winter you won’t be able to grow a winter vegetable garden there.

Trees—yours or those in adjoining lots, are often the biggest obstacle and not just because of their shade. Widely spreading tree roots can suck most of the water and fertility from your garden, even if the tree itself doesn’t shade the area.

In preparation for clearing ground, you’ll need two amendments: well-rotted compost and fertilizer—ideally a Complete Organic Fertilizer (COF; see the sidebar for my recipe). Alternatively, you can use composted steer or horse manure, and a higher-nitrogen amendment like chicken manure. Basically, you need a soil amendment to add humus to the soil, and a higher-nitrogen product to encourage decomposition.

One of the best ways to kill grass without working too hard involves covering the area with corrugated cardboard or lots of newspaper. Do this in September or October. Spread a thick layer of manure or compost plus COF or chicken manure before putting down newspaper or cardboard. If newspapers are watered and sprinkled with soil after spreading them out they will not blow away.  In spring, remove whatever remains of the newspaper and cardboard.

A method that requires a little more effort is to spread manure or compost and COF or chicken manure, and then, before the soil gets too soggy from autumn rains, hand dig the area, once over roughly.

If the soil is still dry from summer, water it first to make digging a lot easier.  Use a sharpened spade or shovel; bite off small chunks only two or three inches thick, a shovel’s blade wide, going as deep as possible flip these chunks over placing the grass side at the bottom where most of it dies of light deprivation. One turn won’t do the job. So after digging and flipping, wait a few weeks and then do it all over again.

If you rototill the plot first before hand-digging, it’ll go much easier because the sod will have been mostly destroyed by the tilling. But tiller tines never go very deep (the fluffy loose soil they create seems deep, but after it settles back down it becomes clear that the soil was only loosened four to six inches down). So it is wise to hand-dig to a full shovel blade’s depth after rototilling.

In every case—fertilize, dig, till, or cover—if this work is completed by the end of October there is nothing else to do until spring comes except to allow winter weather and the passage of time to work on your soil. Then in March or April spread another dose of COF or chicken manure compost and then turn the soil over once. Digging will be easy! Any weeds and grasses that have arisen during the winter will be small, young and tender; the wiry root masses from the old sod will have decomposed. You’ll now have crumbly, open fertile soil that will grow vegetables excellently.

Unless, that is, you are working with clay soil. That heavy, hard-to-work stuff needs to be amended with quite a bit more compost the first time you work it up. Instead of spreading an inch-thick layer of manure or a half-inch of compost, on clay spread two to four inches before going to the next steps as outlined above. Once your clay garden is a going concern it should not require any more organic matter to keep it going than any other sort of soil.

Steve Solomon is author of the Northwest Gardening classic, Growing Vegetables West of the Cascades. The 6th edition was published in 2007 by Sasquatch Press, Seattle. Steve started Territorial Seed Co. in the 1980s and now lives in Tasmania.