Window boxes are the original apartment garden. Before grow lights and hydroponic systems, city dwellers grew herbs on their windowsills in simple wooden or terracotta boxes — and it worked then, and it works now. A south- or west-facing window can support a year-round herb garden of basil, parsley, chives, and mint. A sunny balcony railing can hold enough tomatoes for salads all summer.
The challenge is finding a window box that fits your specific situation — the right length for your sill, adequate drainage so roots don't rot, and secure mounting that won't shift or fall in wind. We compared five options across different balcony and windowsill setups to find which ones hold up in real apartment conditions.
Our Top Picks at a Glance
- Best Overall: Classic Home & Garden Poly Window Box — durable, good drainage, versatile sizes
- Best Self-Watering: Lechuza Balconera — water reservoir eliminates daily watering
- Best Large: Keter Easy Grow Planter — 17-gallon capacity, self-watering, railing mount
- Best Compact: Window Garden Slim Planter — small footprint, suction-mount for glass
- Best Budget: Elho Green Basics Balcony Box — lightweight, recycled plastic, sub-$20
What to Look for in a Window Box Planter
- Drainage holes: Non-negotiable. Standing water kills roots. Every planter should have multiple drainage holes at the bottom, or a water reservoir system with a separate fill port (self-watering planters).
- Size: Match to your sill or railing dimensions. Standard window boxes come in 18, 24, and 36-inch lengths. Measure before buying — a box that overhangs significantly is a safety hazard.
- Material: Resin/poly boxes are lightweight, UV-resistant, and won't crack in cold weather. Wood looks beautiful but requires treatment to prevent rot. Terracotta is heavy but has excellent breathability for roots.
- Mounting: Sill-sitting planters work for wide ledges. Railing-mount planters clamp to balcony railings. Some planters include both mounting options. Check weight limits on your balcony railing before mounting heavy planters.
- Self-watering reservoir: A reservoir lets you water less frequently — critical for apartment dwellers who travel or have irregular schedules. The reservoir stores excess water that roots absorb as needed.
- Color and appearance: You'll see this box every day. Choose one you like looking at — the practical options come in enough colors that aesthetics don't require sacrifice.
Window Box Planter Comparison
| Planter | Price | Self-Watering | Material | Best For |
|---|---|---|---|---|
| Classic H&G Poly Box Top Pick | ~$25 | No | Resin/poly | Best overall |
| Lechuza Balconera | ~$60 | Yes — reservoir | Resin | Best self-watering |
| Keter Easy Grow | ~$80 | Yes — reservoir | Resin | Best large capacity |
| Window Garden Slim | ~$30 | No | Plastic | Best compact/window |
| Elho Green Basics | ~$18 | No | Recycled plastic | Best budget |
Our Top Window Box Planter Reviews
Classic Home & Garden Poly Window Box
The Classic Home & Garden poly window box is what you'd find if you distilled every positive attribute of a good apartment planter into one affordable package. The UV-stabilized resin won't fade, crack, or warp through multiple seasons of sun and frost. Drainage holes are properly sized and positioned. The box is available in 18, 24, and 36-inch lengths in multiple colors, making it easy to find the right fit for your sill.
Weight is excellent for a planter this size — the 24-inch version weighs just over a pound empty, so filled with soil it's manageable without being dangerous. The interior depth is 6 inches, which is adequate for most herbs and annual flowers. Owners growing basil, parsley, and marigolds in the 24-inch box report a full season with no problems — good root depth, consistent drainage, and plastic that holds up without discoloration.
Pros
- Available in multiple lengths and colors
- Lightweight UV-resistant resin
- Proper drainage holes
- Affordable price point
- 6" interior depth for herbs and annuals
Cons
- No self-watering reservoir
- Standard plastic look (not the most decorative)
Lechuza Balconera Self-Watering Planter
Lechuza is a German brand that has engineered some of the best self-watering planters on the market, and the Balconera is their flagship window box. The integrated sub-irrigation system holds a water reservoir at the bottom of the planter — roots grow down toward the water and take what they need, eliminating the overwatering and underwatering cycles that kill most apartment plants. The fill indicator tells you when to add water, and in good weather you may only need to refill every 7–14 days.
The planter also includes railing clips that fit most standard balcony railings (round and square), and a drainage plug that lets you switch between reservoir mode (recommended) and direct drainage mode. The build quality is exceptional — the resin is thick, the reservoir mechanism is reliable, and the design is clean and contemporary. For apartment dwellers who travel frequently or simply forget to water, the Lechuza transforms balcony gardening from stressful to easy.
Pros
- Sub-irrigation system — water 1-2x per week
- Water level indicator
- Railing clips included for most balcony types
- Excellent German build quality
- Contemporary design aesthetics
Cons
- Significantly more expensive than standard planters
- Reservoir system adds complexity if it malfunctions
Keter Easy Grow Elevated Planter Box
The Keter Easy Grow is in a different category than standard window boxes — it's a large-capacity planter (approximately 17 gallons) on an elevated stand, designed for balconies rather than windowsills. For apartment dwellers with a balcony who want to grow more than herbs — tomatoes, peppers, salad greens, dwarf fruit plants — the Keter provides the soil volume needed for productive food crops.
The integrated self-watering reservoir is substantial, and the stand elevates the planter to a comfortable working height so you don't have to bend to tend your plants. The resin construction is UV-stable and weather-resistant. Assembly is straightforward with no tools required. This isn't a windowsill planter — it's a balcony garden in a box, and for apartment dwellers who want to grow real food, it's the most practical large-scale option available.
Pros
- 17-gallon capacity for vegetables and larger plants
- Elevated stand — comfortable working height
- Self-watering reservoir
- Durable UV-stable resin
- No-tool assembly
Cons
- Too large for windowsills — balcony only
- Most expensive option on this list
- Takes up meaningful balcony floor space
Window Garden Slim Planter Box
For apartment dwellers with narrow windowsills or interior windows that get good indirect light, the Window Garden Slim Planter is a clever solution. It's designed to sit in the window itself using suction cups, rather than on a sill — the planter is pressed against the glass and held securely by suction mounts. This works for herbs that don't get direct sun (chives, parsley, mint) and microgreens.
The design keeps everything contained against the window with a drip tray that catches any drainage — important for interior windows above wooden floors or carpeting. Available in several sizes to fit standard window pane dimensions. The clear back panel lets in light from both sides of the planter, benefiting plant growth. Not suitable for large or heavy plants, but for a compact kitchen herb garden it's one of the most practical space-saving solutions available.
Pros
- Suction mounts on glass — no sill needed
- Drip tray included for interior use
- Clear back for double-sided light
- Very compact footprint
Cons
- Limited to lightweight herbs and microgreens
- Suction cups require flat glass surface
- Small soil volume limits plant size
Elho Green Basics Balcony Box
Elho is a Dutch brand that manufactures planters from 100% recycled plastic — a genuine environmental consideration for eco-conscious apartment gardeners. The Green Basics balcony box is their entry-level window box, and it performs reliably for the price. Standard drainage holes, a solid rectangular shape that fits most sills, and a range of earthy colors (anthracite, living black, stone green) that look more intentional than the typical budget plastic planter.
The 50cm (roughly 20-inch) version is the most popular size and fits standard European-style window boxes and most American sills. For apartment gardeners who want a functional herb box without much investment — or want to try window gardening before committing to a nicer planter — the Elho is the most defensible budget choice. The recycled plastic construction is more durable than the cheapest options.
Pros
- Made from 100% recycled plastic
- Attractive earthy color options
- Functional drainage
- Very affordable
Cons
- No self-watering feature
- Limited soil depth for larger plants
- Quality below premium options
What to Grow in an Apartment Window Box
Best herbs for window boxes
Basil, chives, parsley, cilantro, mint (keep it contained — it spreads aggressively), and thyme all thrive in window boxes with at least 4–6 hours of sun per day. Mint and chives tolerate lower light better than basil, which needs 6+ hours. Most culinary herbs prefer 5–7 inch soil depth — a standard window box works perfectly.
Best flowers for window boxes
Petunias, geraniums, nasturtiums, and lobelia are traditional window box flowers that tolerate the root restriction of a planter well. Nasturtiums are also edible — you can eat the flowers and peppery leaves. Trailing varieties that drape over the edge of the box create the classic European window garden look.
Vegetables in window boxes
Lettuce and salad greens are ideal window box vegetables — they're shallow-rooted, productive in small spaces, and can be harvested continuously with a cut-and-come-again approach. Cherry tomatoes need a deeper box (8+ inches) and a sunny south-facing exposure, but compact varieties like Tumbling Tom are bred for container growing. Radishes and green onions are also productive in standard window boxes.
Frequently Asked Questions
For sill-mounted boxes, use a planter bracket — L-shaped metal brackets that mount under the box and screw into the window frame or exterior wall. Always check that the sill is structurally sound before placing a filled planter on it. For railing-mounted planters, use railing clips designed for your railing profile (round or square) and check the weight rating against your filled planter weight. A 24-inch box filled with moist potting mix can weigh 15–20 lbs. In areas with high winds, use a secondary safety cable or rope attached to the structure as a backup.
Use a high-quality potting mix — not garden soil, which is too dense for container planting and can compact to the point where roots can't penetrate. Look for a mix specifically labeled for containers or vegetables that contains perlite or vermiculite for drainage. Add slow-release granular fertilizer at planting time, and liquid fertilize every 2–3 weeks through the growing season. Container plants need more frequent fertilizing than in-ground plants because watering leaches nutrients from the potting mix over time.
Window boxes dry out faster than in-ground beds because the soil volume is small and the box is exposed to wind on multiple sides. In summer, daily watering is common for south-facing boxes in full sun. Check moisture by inserting your finger 2 inches into the soil — water when it's dry at that depth. Self-watering planters with reservoirs significantly reduce this frequency; depending on plant size and weather, you may only need to refill the reservoir once or twice a week. Water in the morning so foliage has time to dry before nightfall, reducing disease risk.