Successful vegetable gardens need at least 6 hours of direct sunlight per day, but you can make do with 4 to 6 hours. Some vegetables are able to handle slightly shadier situations; spinach, lettuce, scarlet runner beans, turnips and rutabagas are a few examples. These vegetables will enjoy some cool-light shade during the heat of the summer.
More than anything else, proper soil preparation will influence the quality and productivity of your crops. You can prepare the soil in the fall or spring. It is simply a matter of preference; do what works best for your schedule. In the spring, start working in your garden when the soil is moist but not soggy; if it is too wet you will compact your soil.
Amend your soil with compost or dehydrated manure (bagged, composted manure). Add what you can. For a new garden, 1 to 4 inches is recommended, depending on the soil. For an established garden, generally 1/2 to 1 inch is ideal, but you can often get get away with less (1/4 inch). When it comes to amending soil, regularly amending is more important than a large quantity of material (which can get intimidating). If it is your first year gardening, get a soil test from your local cooperative extension.
Use a spading shovel or garden fork to loosen and turn the soil, breaking large clumps as you go. Move backwards as you work, so that you do not compact soil that has been turned. Finally, rake the soil smooth and you are ready to plant.
Soil preparation is important for several reason. Plants need water, nutrients and oxygen to grow. When you turn the soil and amend it with compost, you are aerating it, improving soil structure and friability, and thereby increasing its capacity to hold water. Healthy soil amended with compost makes for healthier plants that are not only prolific by also more disease-resistant. Fertilizers such as fish emulsions and seaweed, which are popular in the vegetable world, are vitamin pills for plants, a nice boost but not the main meal.
When planting seeds, read the package for specific planting directions, but the general rule for planting seeds is at a depth 2 to 3 times their diameter. Plant your seeds in small furrows that can be made with a hoe edge, a stick or your finger. Vegetable rows should run north-south to give the plants equal exposure to the sun. The rows should be far enough apart to allow space for the full-growth plants. If you are planning to walk through the rows, leave an additional 12 to 24 inches for a path.
Space seeds evenly when you plant them in the furrow. One easy technique is to crease one side of the seed packet and slowly tap or shake the seeds out of the "v" that is formed. You will have to thin the seedlings regardless of how carefully you plant. It is better to start off with too many than too few in case some of the seeds do not germinate.
Cover the seeds, lightly tamp down the soil to ensure good seed-soil contact and gently water them in. If there is no rainfall, check daily to see if they need water. The soil should stay damp (not wet). Water with a watering can that has a rose (a spout cap with small holes) until they germinate. Sprinklers are fine once the garden is established, but not during the initial stages when tiny seeds are lying just below the soil surface.
Mulch your vegetable beds once they are planted and the soil has warmed up. Add an extra layer of compost around your tomatoes. Mulch rows by laying down newspaper and covering it with straw. Remember to wet the newspaper before you lay down the straw and then wet the straw so it doesn't blow away. Mulch will minimize weeding and retain moisture. If you apply straw mulch around your zucchini, squash, pumpkins and melons, your vegetables will have a dry surface to grow on.
Succession planting is an important part of any vegetable garden. There are crops that can be started early in the season, but they often begin to wane in the summer heat. Peas can be planted as early as St. Patrick's Day. Lettuce can be grown throughout the season--there are early, summer, and late varieties. Some of them tolerate the heat better than others, and most take a siesta during the summer. After crops are grown and harvested, that space can be claimed by another variety or another vegetable.
Space is at a premium in the vegetable garden. Radishes can be planted between rows of head lettuce--they will be harvested long before the lettuce expands to take over the space. Mustard greens can be pulled out and replaced by a late-season planting of Swiss chard. Peas can be replaced by late-season pole beans.
There are many cool-season crops and warm-season crops to choose from. There are many varieties that mature at different times. For example, if you are planting tomatoes, you can have varieties that mature in 60, 70, and 80-day intervals, so that you don't get overwhelmed by a single massive harvest. Fast-producing crops such as lettuce are often sown at 2 to 3 week intervals for the same effect.
Here are some suggestions for both cool-season and warm-season crops:
Warm-season crops can be started indoors, typically 6 to 10 weeks before they are ready to be planted outside. Make sure potting soil is moist and has good drainage. To prevent fungal diseases, use sterilized pots, soil and labels. Sow seeds, water and cover the pots with plastic bags or covers, and place in a warm, sunny spot. Once the seeds germinate, remove bags or covers.
Remember to harden off your seedlings. Over the course of one week, take your seedlings outside, increasing the time by one hour every day. Do not place them in the blazing sun or in a windy site. After the week, your young seedlings will be ready to brave the elements and can be planted outdoors.
The Vegetable Gardener's Bible by 
Taylor's Weekend Gardening Guide to Kitchen Gardens by 
