Chickweed will mainly be a problem in the spring and fall garden since it is a cool-season weed. For a small garden, it may be easiest to pull weeds by hand or lightly cultivate with a hoe. Applying a layer of mulch around plants will also discourage weed growth. There are herbicides available for the home garden that are effective at preventing germination of most annual weeds. Check the label to make sure the plants in your garden are listed and will not be affected by the herbicide. Some herbicides can be safely applied in late fall or late winter before weeds emerge. Contact your local Extension office for herbicide recommendations.
You may want to the read the following Iowa State University publication:
Weed Control in the Home Garden