Creating a mini lavender garden in an outdoor plant box is a delightful way to bring fragrance and beauty to your space. Start by selecting a sturdy plant box with proper drainage holes to prevent waterlogging. Fill it with well-draining soil mixed with sand or gravel, as lavender thrives in dry, sandy conditions. Choose compact lavender varieties like 'Hidcote' or 'Munstead' for smaller spaces. Plant the lavender seedlings 12-18 inches apart to allow airflow and prevent overcrowding. Place the box in a sunny spot, as lavender needs at least 6-8 hours of sunlight daily. Water sparingly, letting the soil dry between watering to avoid root rot. Prune lightly after flowering to maintain shape and encourage growth. With minimal care, your mini lavender garden will bloom beautifully, attracting pollinators and adding a touch of serenity to your outdoor area.