Want to grow fresh herbs in your urban space? The key to success lies in providing enough room for their roots. While needs vary, a general rule is a planter box depth of 6 to 12 inches (15 to 30 cm). This range accommodates most popular culinary herbs.
For herbs with shallow root systems like basil, cilantro, chives, and parsley, a depth of 6-8 inches is sufficient. Herbs such as mint, thyme, and oregano are moderately deep-rooted and thrive in 8-10 inches of soil. For larger, woody herbs like rosemary, lavender, and bay laurel, opt for a deeper planter of 12 inches or more to support their extensive root growth and ensure stability.
Always ensure your planter box has adequate drainage holes. Pair the correct depth with quality potting mix, ample sunlight, and consistent watering for a bountiful, compact herb garden right on your balcony or windowsill.