Creating a beautiful and productive mixed garden in urban planter boxes is an art that combines aesthetics with practicality. The best arrangement follows key principles of companion planting, vertical layering, and thoughtful design. Start by considering the "thriller, filler, spiller" concept used by floral designers. Place a tall, structural "thriller" plant like a tomato, pepper, or sunflower in the center or back of the planter. Surround it with medium-height "filler" plants such as lettuce, bush beans, or marigolds. Finally, add trailing "spiller" plants like nasturtiums, sweet potatoes, or herbs at the edges to cascade over the sides.
Companion planting is crucial for a healthy mixed garden. Pairing beneficial flowers with vegetables can deter pests and improve growth. For instance, plant basil alongside tomatoes to enhance flavor and repel flies, or use marigolds throughout the planter to discourage nematodes. Borage is excellent near strawberries and squash, attracting pollinators. Always group plants with similar sunlight and water needs together. Place sun-loving plants like rosemary and zinnias on the sunny side, while shade-tolerant plants like lettuce and impatiens can occupy shadier spots.
Vertical layering maximizes space in limited urban settings. Use trellises or cages for climbing plants like peas, cucumbers, or pole beans at the back of the planter. This creates a living wall that provides structure and allows shorter plants to thrive in front. For deep planters, consider layering roots: plant deep-rooted vegetables like carrots or tomatoes alongside shallow-rooted flowers like alyssum or herbs like oregano.
Aesthetic balance is key to an appealing arrangement. Create visual harmony by considering color, texture, and form. The vibrant red of cherry tomatoes can be complemented by the purple blooms of lavender or the yellow flowers of nasturtiums, which are also edible. Mix the fine texture of carrots with the broad leaves of Swiss chard and the delicate petals of calendula. Remember to leave adequate space for growth and ensure your planter has sufficient depth and drainage for both your floral and edible plants to thrive in their shared urban environment.