Your new garden needs sunlight. While there are some leafy green vegetables that grow in part shade, almost all vegetables and fruits are far more productive if they get at least 6 hours of sunlight each day. Ideally, those 6 hours happen in the morning and/or early afternoon; afternoon sun is the hottest and therefore sucks more water from the soil. So how do you determine if a potential garden site gets that much sun? By observation.
The old fashioned way of doing this is, in my opinion, the best. First thing when the sun comes up, go out into the garden, and sprinkle any shaded areas with flour. Then go out into the garden at noon and do the same thing. And finally, at around 3 pm, do this again. To make things more clear, use something to differentiate between the three different markings; for example, divide each area with an inch wide "line" where no flour falls, or use a hose to mark off the different area. Now you should have a clear idea of the sunniest spot in your yard; plant your garden there.
|From The New Garden Encyclopedia, 1943|
A similar method is to draw a rough map of your potential garden area (or whole yard) on a piece of paper. Beginning when the sun rises, go out in the garden and note where it is shady. Lightly color in corresponding areas on your map. Go out again every hour (or at the very least, at noon and about 3 pm) and do the same thing. Make sure the shade on your map is a different color, according to the time of day represented. (At Get Busy Gardening, they use a slightly different notation method. Choose whatever makes most sense to you.) From your map, you should be able to easily tell how much sun any given area receives.
A newfangled way to test a spot for sunlight is to use an electronic sunlight meter. Stick the meter into the soil first thing in the morning (just before sunrise), and remove when night falls. The meter will tell you whether or not the location gets full sun. The only problem with a meter like this is that it only reads the specific location where it's put. To read an entire garden site requires many days of moving the meter around.
Now a word of caution: Sun exposure changes according to season, so don't expect that a shade map made in winter will accurately represent the shade in summer.
Naturally, water is essential for a garden. While some areas generally get enough rainfall to support a vegetable garden, drought will be a huge problem unless your garden has reasonable access to irrigation water. I recommend having your garden near enough a water spigot that a hose can reach all part of your garden with ease.
Certainly, soil health is a vital aspect of a productive garden - but as long as you're willing to bring in decent soil, poor soil in your chosen garden location isn't detrimental. To learn more about what type of soil you have, click here. If, after testing your soil, you determine it's not very healthy, be sure to read up on how to combat the situation.
Gardening From Scratch, Part I: Do Your Research
Gardening From Scratch, Part III: Preparing the Garden Bed