You can grow a vegetable garden in a small space that will produce a large quantity of vegetables if you practice intensive gardening. Intensive gardening is planting and harvesting crops in such a way so as to maximize the available space and never leave any portion of your garden bare of seeds or plants. Improve the soil in your small space vegetable garden and it will grow many more vegetables than its small size will lead you to believe.
Sow two or more varieties of vegetables close together in the same space. Plant one that matures quickly and one that takes longer to mature. One will be harvested long before the other one needs the space. For example, plant cool-weather-loving lettuce and salad greens alongside green beans. By the time the lettuce is harvested, the beans will be large enough to need the space. Another popular interplanting technique is to plant carrots and radishes in the same row. The radishes germinate quickly and mature within about 30 days, while the carrots can take up to 28 days just to germinate. By the time the carrots have germinated and come up, the radishes are ready to harvest. Pull the radishes and the carrots will take over the space.
Succession planting is the practice of replanting your garden space to a new crop immediately after you harvest another crop. For example, cool-season crops planted in spring are harvested before hot summer temperatures arrive. As soon as they are harvested, immediately re-plant hot-weather-loving vegetables in the same space. When these are harvested in late summer, immediately re-plant the area with cool-weather-loving vegetables for fall harvest.
Most plants don't need to be planted in neat rows with wide open spaces between them. Plant intensively in wide rows in a grid pattern, spacing them the same distance apart in all directions. Nearly all garden vegetables can safely be planted closer together than the spacing recommended on their seed packages.
Grow Crops Vertically
Vegetables that grow on vines can be grown vertically and will take up much less space than if they are allowed to ramble along the ground. You can construct a simple trellis using PVC pipes for the upright supports and black plastic netting strung between them. Another possibility is to plant your garden along a fence and use it for your vine crops to climb upon.
Maintain Soil Fertility
Maintaining the fertility of your soil is crucial to harvesting the most vegetables possible from a small space. Add peat moss and well-rotted manure to the garden bed prior to planting your crops in spring. Maintain a compost pile and add all pulled weeds, thinned plants, and fruit and vegetable trimmings. Turn the pile weekly and it will decompose and turn into rich, black soil over the course of a growing season. Another way to increase the fertility of your soil is to plant a cover crop of annual ryegrass in autumn after you have harvested all the plants. Turn the grass into the soil in early spring and it will add both fertility and structure to your garden soil.