You may have heard of cover crops (AKA green manures or living mulches). Cover crops are a crop you plant in your garden during times when your main vegetable crops aren't growing. Wintertime is a great time for cover crops. Plants commonly used as winter cover crops include wheat, clover, vetch and rye. The seed for these plants is very inexpensive and is available at your local garden center or feed store. They are also available through mail-order sources.
Cover crops can be a simple and attractive way to boost your organic garden's vegetable growing potential. They add visual interest to your garden with their green color and blossoms during the winter and early spring months. These crops help your garden ecosystem in many different ways.
Attracting beneficial creatures: Cover crops provide habitat and food for beneficial insects, toads and birds. As cover crops grow, they also provide a home for soil creatures such as earthworms.
Building and protecting your soil: The roots and leaf canopy of cover crops help prevent soil erosion. The biomass produced by the crop helps to build your soil's organic matter.
Killing weeds: Fast-germinating cover crops that have large, spreading canopies outgrow and choke out weeds. Some cover crops also produce compounds that prevent weed seeds from sprouting.
Adding nutrients: When you use a nitrogen-fixing crop such as clover or vetch, you are adding nitrogen to your soil. This will allow you to reduce the amount of compost or other organic fertilizers that you will have to provide to your vegetable crops. Cover crops can also scavenge for nutrients such as phosphorus and make them more available to your vegetable crops.
Suppressing diseases and insect pests: Using cover crops in your garden can stop the cycle of plant diseases. This is because rotating between different types of crops helps keep soil-borne diseases and insect infestations in check. Some winter cover crops actually deter soil pests and diseases from setting up shop in your garden.
There really is no one answer as to what the best plants to grow in a garden are because flowers, and plant arrangement are very much like an art. How one weaves colors and textures into a tapestry or mosaic upon the canvas of a yard is probably different every time.
Successful low-cost gardening requires patience. If you forego instant gratification, and patiently scout for your needs, you'll have a great low-cost Garden. Your cost depends on your time and patience.