Yes, you can use an urban planter box indoors during winter and move it outside later, but it works best when you plan for drainage, light, weight, and a gradual transition. An urban planter box is usually designed for outdoor use, so bringing it inside does not automatically harm it—but the indoor environment is different. Check that the box has drainage holes. If it does not, use it as a decorative outer container with planted pots inside, or add drainage carefully. Always place a waterproof saucer or tray underneath to protect floors and prevent moisture damage. If the planter is large and heavy, put it on a wheeled dolly or casters before filling it, and avoid moving it when it is full of wet soil. You may need to empty some soil or use a lightweight potting mix to make the move safer.
Light is the biggest limitation in winter. Most edible plants and flowering plants need at least six hours of direct sun or a grow light for 12 to 14 hours per day. A sunny south-facing window can work for herbs, lettuce, kale, and other leafy greens, but fruiting plants like tomatoes and peppers usually need stronger light and more space. Keep the planter away from cold drafts, radiators, and heat vents. Water less often than you would outdoors, because indoor winter growth is slower and soil can stay wet for longer. Good airflow also helps prevent fungus gnats, mold, and damping-off.
Before you move the planter back outside, harden off the plants gradually. Do not move them from a warm room to full sun and cold wind in one day. Start with one or two hours in a shaded, sheltered spot, then increase the time over seven to ten days. Bring the planter back inside at night if temperatures drop near freezing, and check the forecast for your last frost date. Choose plants that suit your climate and indoor conditions, and inspect the soil and leaves for pests before the move. With drainage, bright light, careful watering, and a slow transition, an urban planter box can serve you indoors in winter and outdoors again when the weather warms.