Plan your garden. Are you looking to grow a theme garden, such as the ingredients for salsa or spaghetti sauce? Do you want to provide a learning experience for your children by letting them tend a few veggie plants? Or are you looking to share the fruits of your labor with friends or a food bank? Think of the vegetables and fruits your family loves and plan how they'll fit into the space.
Remove any sod from your garden space.
Cut straight down into the soil with a hand trowel, retrieving a three-inch sample of soil. Avoid areas of decaying debris, if possible, and take multiple samples if your garden is large. Place the sample(s) in a clean plastic container and take it to your local cooperative extension office or full-service garden center for testing. The test, which could cost just a few dollars, if anything, will reveal the soil's pH level, nutrient amounts, drainage capabilities and any other important information about your soil's ability to grow healthy foods.
Purchase any amendments as suggested by the testing. Sand and peat moss can help fix drainage issues. Compost and manure will help with nutrient deficiencies, while lime can help amend pH balance. Most of California's native soil is not nutrient-sufficient for growing vegetables without a heavy dose of amending year after year.
Turn amendments one at a time into the soil 12 to 18 inches deep with a shovel until the soil is a loose, powdery consistency.
Select plants and seeds suited for the unique climate issues of California by visiting local full-service garden centers. Be sure that online or catalog purchases are suited for your particular growing zone. Heirloom tomatoes that thrive in the Midwest, for example, will not survive in most California climates.
Plant seeds and seedlings as per the instructions on the individual seed packets or plant tags. Follow spacing and special instructions completely for best results. Face rows east to west with the tallest plants to the north to maximize the sun exposure. Cool-weather plants such as beets, lettuces, greens, peas, spinach, and broccoli can be grown year-round in most zones in California. Warm-season plants such as tomatoes, corn, peppers, squash, cucumbers, and melons must be planted after the danger of frost, if applicable for your growing zone.
Place tomato stakes or cages, trellises for cucumbers or pole beans, and other support systems in place. Adding stakes at the time of planting helps avoid later damage to growing roots.
Lay a 2-inch layer of straw down to help suppress weeds and retain moisture. Straw, unlike wood mulches, breaks down slowly without removing nitrogen from the soil in the decomposition process.
Water and weed garden regularly. The amount of water needed each week varies for different types of plants, so research your selections for best results. Tomatoes, for example, need about a gallon of water a week and may rot if watered daily while vined veggies, such as beans and cucumbers, need a more regular watering schedule. Adhere to your local water regulations when watering and practice water conservation techniques.
Rotate your garden. In much of California, you have the benefit of growing year-round. As you harvest cool-weather veggies, plant warm-weather in their place. As they are spent, plant more cool-weather. If you keep replacing plants when you harvest, you will always have some fresh choices for your table.