Zone 8 is characterized by mild winters in which temperatures rarely dip below 10 degrees Fahrenheit and temperate summers in which temperatures may reach an extreme over 100 degrees Fahrenheit. Vegetables can be grown from mid spring to mid fall in the ground, and year-round in a greenhouse with protection from the cold. Because of the long growing season, gardeners may grow two or even three crops yearly--cool season crops in spring and fall, and warm season crops in summer.
Have your soil tested before planting crops. Zone 8 stretches over a wide range of soils from drainage-poor clay to rich, silty alluvial soils. A soil test can help you determine your soil's structure as well as the pH and which nutrients you should amend into the soil to enrich it. The USDA maintains soil testing facilities in conjunction with the community and continuing education programs operated by land grant colleges in each state and territory of the United States. By contacting your local county extension agent, you can find out how to collect soil samples and where to send them.
Purchase amendments for your soil based on the recommendations made by the soil test in step 1. General amendments that will help improve your garden soil include organic material such as compost and well-rotted manure. Gypsum will help to break up the soil structure of clay soil and to improve drainage. To adjust the pH of your soil, add lime to raise the pH or sulfur to lower it. The optimal pH for most plants is between 6.0 and 7.0. Plants grown in this range of soil will take up nutrients more effectively and will produce fruit and vegetables more abundantly.
Break up your soil with a garden tiller to a depth of 6 inches. Rake over the loose soil to locate rocks, sticks or other large debris and remove them. Spread amendments over your soil with a shovel to a depth of 4 inches. Mix these amendments with the soil by passing the garden tiller over the soil again.
Select plants that are hearty to zone 8. Most cool-season crops such as lettuce and broccoli that have short life cycles can be grown in spring and fall. For summer, choose subtropical vegetables and fruits or heat-tolerant hybrids. Good summer plants include corn, beans, okra and tomatoes.
Determine the last average frost date for your specific region. Typically, the last frost dates for zone 8 are around the first part of April. Plant seeds in the ground two weeks before the last average frost date by digging furrows in the ground that are twice as deep as the seeds that you will plant. Place the seeds in this furrow and cover with soil. Thin sprouts as they begin to grow.
Wait until after the last frost date of the year to plant seedlings. Dig a planting hole that is twice as wide as the root ball and place the root ball in the planting hole. Cover with dirt and pat the soil to remove any air pockets. Water frequently to keep the soil as damp as a wrung out sponge. This will allow the roots a chance to develop.
Keep an eye on the temperatures, and water frequently in the mornings during mid to late summer. Summer plants in zone 8 rarely receive enough rainfall in late summer to nourish the plants.