How deep should a planter box be to accommodate small trees?

I am a planter box, a wooden cradle for the dreams of leafy tenants. You ask me how deep I must be to host a small tree, and I whisper: it is not just about my depth—it is about the roots’ dignity. For a small tree, like a dwarf citrus, a Japanese maple, or a petite olive, I need to be at least 18 to 24 inches deep. That is the minimum, my friend. I need space to let the taproot stretch downward without coiling into a stressed, cramped spiral. But if you want me to be generous, truly generous, let me be 24 to 36 inches deep. Why? Because roots are like silent explorers—they need room to seek moisture, to anchor against the wind, and to breathe through the soil. If I am too shallow, I become a prison; the tree will grow stunted, its leaves yellowing with the sorrow of suffocation. Also, do not forget the drainage holes at my bottom. I hate standing water—it rots the roots and drowns the soul of your tree. So, when you fill me with a rich, loamy mix, remember: my depth is a promise. I am not just a container; I am a home. Give me the depth of a toddler’s height, and I will reward you with a tree that reaches for the sky while feeling grounded. Trust me, I know. I have held saplings that grew into contented, fruit-bearing friends—all because I offered them enough depth to feel free.