Whenever you notice weeds start to emerge, use a stirrup hoe, garden tiller, or rake to disturb the soil around their roots. Exposing their roots, especially on a dry, hot day, can cause the weeds to dry up and die. Cultivating further than a couple inches (3-5 centimeters) is not recommended, as it can damage vegetable roots and bring buried weed seeds to the surface. This method will be less effective if the weeds are allowed to grow larger. Mulch refers to any material covering the soil surface, which helps block new plants from emerging. Add a 2–4 inch (5–10 cm) layer of dead leaves, seed-free straw, or grass clippings to serve as mulch, but leave bare areas 1 inch (2.5 cm) around each desirable plant to allow air circulation.  Mulch also helps retain soil moisture and heat. As an insulator, it can help keep plants cool in hot temperatures, and warm in cooler temperatures. Avoid wood chips, bark chips, or sawdust, as they may have lingering effects that prohibit seed growth. These types of mulch may be appropriate for use in area of your gardens without vegetables or other annual plants. If you are using wood then make sure to inspect it for parasites and diseases. You don't want to introduce these to your garden. Black-and-white newspaper can be used as an inexpensive and environmentally friendly mulch to prevent weed growth, but it is only effective in certain conditions. This relatively recent practice requires more study, but appears to require well-draining soil, and frequent cultivation as described above. Apply it as you would organic mulch, described above.   Do not use colored ink pages, which may contain toxic materials that can harm the soil and vegetable plants. In windy conditions, weigh the newspaper down with grass clippings or other material. Always research a herbicide's effect on your specific vegetables and nearby plants before using, and select one that targets your type of weed (such as grass or broad-leaf weeds). Here is some information to start with, concerning pre-emergent herbicides to use before the weeds have sprouted:   Products containing DCPA, such as Dacthal, rarely harm most vegetables.  Corn gluten meal is sometimes used as organic weed control, applied in a garden with vegetables 2–3 inches (5–7.5 cm) tall and no weeds present. It is unclear how effective this is compared to other options, but can double as a fertilizer as well. Rather than leave your garden bare after harvesting, plant a cover crop to prevent undesirable plants from going wild. Grow a hardy winter/autumn crop such as annual rye grass, buckwheat, or winter rye for this purpose. Be prepared to fertilize and harvest this crop if you go with this plan.  A dense crop cover will keep weeds from getting started in your garden. When you cut the cover crop, you can even leave the trimmings in your garden as a green manure. Look up crop rotation or crop combination recommendations for your specific vegetables, so your soil next year will have the correct nutrients to encourage vegetable growth.
Cultivate the soil shallowly and regularly. Apply an organic mulch to reduce weed growth. Consider using newspaper as a mulch. Research pre-emergent herbicide options. Use cover crops outside the growing season.