Cottage gardens started as a way to grow vegetables, flowers, herbs, and fruits for the kitchen and home use. Flowers were used to cover up unpleasant scents, as seasonings in cooking, and occasionally for medicinal purposes.
The cottage garden was a pleasant and practical jumble of veggies and flowers. As yards became more formal with designated areas for play, lawn, patio and gardens, the separation between veggies and flowers began to widen. There isn't any reason why flowers and veggies can't be mixed.
Choose plants that have the same requirements of sun, soil and water. Look at the area that has been selected for planting. Review the amount of sun and shade it receives. Some vegetables--those that fruit, like green peppers and squash--require more sun than others, like spinach and celery.
Sketch out the garden area on paper and plan the flower and veggie combinations for spring, summer and fall. As you plant, make notes on the paper on what worked and what didn't for the next season.
Plant shorter plants in front for a border, then medium size plants and finally tall plants. For example: marigolds and lettuces for the edging of the border; tomatoes, green peppers and zinnias for the middle of the bed; sunflowers and corn for the back of the bed.
Grow sturdy taller flowers, such as hollyhocks, as support for climbing vegetables such as English peas, snap peas and pole beans.
Plant cooler season vegetables with cooler season flowers and warmer season flowers with warmer season vegetables. The example above is a warmer season combination. A cooler season combination could be lobelia and cabbages for the edging, snapdragons and broccoli for the middle, and snap peas up trellises for the back row.
Compose a completely edible garden by using flowers that are edible with vegetables. Marigolds, nasturtiums, snapdragons, dianthus, roses, lilies and carnations are a few edible flowers.
Coordinate the colors of the vegetables with the flowers. Ruby red tomatoes with red roses, yellow marigolds with yellow pear tomatoes, and purple petunias with purple eggplant are a few combinations.