Test your soil where you want to grow your garden. Some areas are inhospitable to growing plants, and especially edible ones. Poor building practices lead to the loss of rich topsoil and pollution threatens soil quality. Local extension services will not only test the soil (usually for a small fee), but also offer remedies for soil problems. If there's no reason to suspect a pollution problem in the soil, simple soil tests purchased from a garden center can tell you the pH and nutrient content of the soil.
Choose your edible plants and lay out your design -- don't just purchase whatever is on sale. Plan a mixture of annual plants (which live only a year, such as spinach, tomatoes, squash and many others) and perennial plants (which live year after year, meaning you don't have to re-plant each season). Consider fruit and nut trees, shrubs, fruiting vines and matting herbs to mix in among commonly grown vegetables. Many vegetables appreciate the afternoon shade a tree provides or the weed control that shallow-rooted matting herbs provide. Have a designer help you decide where to place plants so that they'll grow healthy and require minimal care.
Mix up the plants. Rows are useful for machines, but food gardens for the home can be inter-planted, or planted among different varieties, to produce an attractive garden as well as an edible one. Focus less on trying to force the most yield out of each plant, and more on getting the greatest variety of your favorite foods, or foods you'd like to try.
Plant shrubs and trees first, according to your design. These are usually transplants purchased at nurseries or garden centers. Dig a hole twice as wide but no deeper using a garden shovel. Remove them gently from their pot, and set in the hole. Backfill with the original soil plus compost if the soil lacks a strong range of nutrients or is in any way compact. Mulch around the root zone with coarse compost to ensure good establishment, and water in deeply.
Plant seeds indoors if it is still too hot or too cold in the garden for them to germinate. Plant in seed trays with seed starter mix at the depth recommended by your local extension center or by the label on the seed package. Water gently so the seed does not shift.
Transplant into the garden when the plants have at two to three true leaves. Amend the soil in the garden with compost prior to planting to ensure plentiful nutrients for your transplants. Use a hand spade to dig the individual planting holes no deeper than the root ball, and back fill gently. Mulch 1 inch deeper if possible, but do not cover the seedlings or let the mulch come into direct contact with the stem. Water gently and deeply.
Design not only the initial planting ideas for the community garden as you would for the home food garden, but also subsequent years. Gardens change over time, and the community-garden planning committee should have a clear idea of where the garden is going to ensure that there are people to manage each step when the time comes.
Install pathways, storage areas and access areas before planting. Planting annuals in raised beds prevents many problems with runoff, pet damage and compaction. Install raised beds after installing the walkways. Install a fence around the community garden if possible to help prevent vandalism. Vandalism is more problematic in food gardens than decorative gardens, since it can lower the edibility of the food.
Conduct a soil test as you would for the home garden. Amend any problems with the soil according to the recommendations of your local extension service.
Make a copy of the design for each person directing the work on the community garden to reduce confusion, and ensure that each director understands the plan before the planting begins.
Plant trees and shrubs first, as you would for the home garden. Plant annual seeds or transplants, if any, as you would for the home garden.