If you are a beginner container gardener in a city, I would recommend a self-watering rectangular planter box. Look for one about 36–48 inches long, 12–18 inches wide, and at least 10–12 inches deep, with a built-in water reservoir, an overflow drain, and optional casters. This is the sweet spot for an urban planter box: it fits on a small balcony or patio, holds enough soil to stay stable, and makes watering far more forgiving than tiny pots.
Why not start with a stylish round pot or a single herb planter? They can work, but they usually dry out quickly, heat up fast, and leave little room for roots. A rectangular planter uses space efficiently along walls and railings, and a self-watering reservoir solves the most common beginner problem: inconsistent watering. Fill the reservoir once or twice a week, and the soil pulls up moisture as needed. The overflow drain keeps excess water from drowning roots after heavy rain.
Material matters. Food-safe HDPE or durable resin is light, affordable, and easy to clean, which is great for renters. Composite or cedar looks warmer and insulates roots better, but it is heavier and costs more. Avoid very dark metal boxes in full sun because they can bake the soil. Also avoid shallow boxes; for most vegetables and herbs, you want at least 10 inches of soil depth, and 12 inches is even better.
Placement is next. Most vegetables, herbs, and flowering plants need six or more hours of direct sun. Put the box where it gets morning sun and some afternoon shade if summers are intense. If wind is strong on a high balcony, choose a lower-profile box or add casters with locks. Check your building rules and weight limits before filling a large planter with wet soil.
For soil, use a lightweight potting mix, not garden soil. Garden soil becomes heavy and compacted in containers. Mix in a slow-release organic fertilizer at planting time, then feed every few weeks during the growing season. Good beginner plants for this kind of urban planter box include lettuce, spinach, basil, mint in its own pot, chives, peppers, bush beans, determinate tomatoes, and compact flowers like marigolds and petunias.
If you want the simplest possible setup, choose a self-watering rectangular planter with a water-level indicator. That little window or float tells you when to refill, so you do not have to guess. Add a layer of mulch on top to slow evaporation, and keep the reservoir clean. If self-watering boxes are not available or are too expensive, a fabric raised bed or a wooden planter with a saucer can also work, but it will require more frequent checking.
So my recommendation for a beginner container gardener is clear: start with a self-watering rectangular urban planter box, 36–48 inches long and at least 10–12 inches deep, with drainage, a reservoir, and wheels if possible. It is practical, forgiving, and small enough for city growing but large enough to actually harvest something. That one good box will teach you more than five tricky little pots.