There is more to planning a garden than simply choosing plants that will do well in your climate, while fitting into the physical space you can provide them. Much like human neighbors, vegetabless will do best when planted in proximity to plants they "like."
The concept of companion planting has been written about for centuries, and has been around probably since human beings first settled down long enough to discover that plants could be cultivated for use as food. Not long after that, some early farmer noticed that particular plants did better when grown in proximity to certain other plants.
Now, of course, we know that some plants befefit others by adding particular nutrients, or by depleting the soil of a substance that might be detrimental to another plant. Legumes, for example, will add nitrogen to the soil, naturally fertilizing the area. Marigolds produce chemicals that repel certain insect pests.
Here is a brief list of plants along with their companion plants. In some cases plants will be listed that may have a negative impact:
1. Bush Beans -- Beets, Cabbage, Carrots, Celery, Corn, Cucumbers, Eggplant, Lettuce, Pea, Radish, Strawberry, Savory, Marigold
2. Pole Beans -- Carrots, Corn Cucumber, Eggplant, Lettuce, Pea, Radish, Savory, Tansy Beets, Onion
3. Beets -- Bush Beans, Cabbage, Onion, Sage
4. Cabbage Family -- Bush Beans, Beets, Celery, Onions, Tomato, All Strong Herbs, Marigold, Nasturtium Strawberry
5. Carrots -- Bush Beans, Pole Beans, Lettuce, Onion, Peas, Radish, Tomato, Sage Dill Celery Bush Beans, Cabbage, Onion, Spinach, Tomato
6. Corn -- Bush Beans, Pole Beans, Cucumber, Melons, Peas, Squash Tomato
7. Cucumbers -- Bush Beans, Pole Beans, Corn, Lettuce, Onions, Peas, Radish, Marigold, Nasturtium, Savory No Strong Herbs
8. Eggplant -- Bush Beans, Pole Beans, Spinach
9. Lettuce -- Bush Beans, Pole Beans, Carrots, Cucumbers, Onion, Radish, Strawberries
10. Melons -- Corn, Nasturtium, Radish
11. Onions -- Beets, Cabbage, Carrots, Celery, Cucumber, Lettuce, Pepper, Squash, Strawberries, Tomato, Savory Bush Beans, Pole Beans, Peas
12. Parsely -- Tomato
13. Peas -- Bush Beans, Pole Beans, Carrots, Corn Cucumber, Radish, Turnips Onion
14. Peppers -- Onions
15. Radish -- Bush Beans, Pole Beans, Carrots, Cucumber, Lettuce, Melons, Peas, Squash Hyssop
16. Spinach -- Celery, Eggplant, Cauliflower
17. Squash -- Corn, Onion, Radish
18. Strawberry -- Bush Beans, Lettuce, Onion, Spinach Cabbage
19. Tomatoes -- Cabbage, Carrots, Celery, Onion, Mint Corn, Fennel