Wooden urban planter boxes can attract termites, but they do not magically create an infestation on their own. The risk depends on the type of wood, moisture, soil contact, and the termite species already in the area.
Termites feed on cellulose, so any wood that stays damp and touches soil is a potential food source. In cities, subterranean termites often travel through soil and can find planter boxes along foundations, balconies, courtyards, rooftops, and community gardens. A wooden box in direct soil contact is much riskier than a sealed, elevated planter with good drainage.
Untreated pine, spruce, or plywood are especially vulnerable. Pressure-treated wood, cedar, redwood, and naturally resistant species are less attractive, but no wood is completely termite-proof if moisture remains high. Termites may also enter through cracks, mulch, dead roots, or wooden stakes. Once inside, a planter box can become a satellite nest or a bridge to nearby buildings.
To reduce risk, use metal, concrete, composite, or treated wood; line the inside with a waterproof barrier; keep a gap between wood and soil; place the box on feet or pavers; improve drainage; avoid overwatering; and keep mulch and soil below the siding. Inspect regularly for mud tubes, soft wood, hollow sounds, and discarded wings.
If you find termites, do not just spray the box. Remove infested wood, correct moisture problems, and call a licensed pest professional. With good design and maintenance, wooden urban planter boxes can be used, but they need more care than non-wood options.