For an urban planter box shared with pets, choose plants that are non-toxic to both cats and dogs and keep the growing setup itself pet-friendly. Good options include basil, rosemary, thyme, cilantro, dill, lettuce, sunflower, calendula, nasturtium, zinnia, spider plant, and Boston fern. These are generally considered safe if a pet accidentally nibbles a leaf, though “safe” does not mean a pet should eat large amounts. Some pets may still get an upset stomach from eating any plant material, so introduce plants gradually and monitor your pet.
Basil, rosemary, and thyme work well in sunny urban planters and are useful kitchen herbs. Cilantro and dill are also practical choices, while lettuce can fill a cooler corner. For color, sunflower, calendula, nasturtium, and zinnia add height and interest without the high toxicity risk of many ornamental flowers. Spider plant and Boston fern are useful in shadier spots, but keep trailing leaves out of reach if your pet likes to pull on plants.
Avoid common toxic or risky plants such as sago palm, lilies, azalea, rhododendron, oleander, foxglove, tulip and daffodil bulbs, tomato leaves, aloe, lavender, and mint. Many bulbs are especially dangerous because pets may dig them up. Also avoid cocoa bean mulch, which is toxic to dogs, and do not use snail bait, rodent poison, systemic pesticides, or fertilizer spikes where pets can reach them. Use clean, fresh potting mix in a stable, well-draining container, and place it where it will not tip over. If your pet digs, cover the soil with a safe barrier or place a small decorative fence around the planter. Wash your hands after gardening, and check the ASPCA toxic and non-toxic plant list for each variety before planting, since common names can vary. With pet-safe plants, clean soil, and sensible placement, an urban planter box can be a safe and attractive garden feature for both people and pets.