Window boxes are not just for flowers. You can grow food in them. Narrow planters fit on sills, railings, and ledges. This guide lists surprising crops that thrive in window boxes and how to grow them.

Window Box Basics

Depth matters more than length. Aim for at least 6–8 inches of soil. Deeper is better for roots. Drainage holes are required. Use potting mix. Window boxes dry out fast. Water daily in summer. South or east exposure works best. North-facing boxes suit shade-tolerant crops.

Herbs That Thrive in Window Boxes

Basil, parsley, cilantro, chives, and thyme fit easily. Mint works but can take over. Plant it alone or in a separate pot. Oregano and rosemary need good drainage. See our indoor herb garden guide for year-round production. Herbs are high value per square inch.

Salad Greens

Lettuce, arugula, spinach, and mixed greens grow well. Sow seeds thinly. Cut outer leaves as needed. Baby kale and mustard greens add variety. Most greens need 4–6 hours of sun. They bolt in heat. Shade or afternoon relief extends the season.

Surprising Window Box Crops

• Strawberries — Everbearing varieties in a 6–8 inch deep box. Hang over the edge or trail. High value.
• Radishes — Quick crop. Round varieties fit. Harvest in 3–4 weeks.
• Green onions — regrow from store-bought roots. Cut tops, leave bulb, regrows.
• Baby carrots — Short cultivars like Parisian. Need 8+ inch depth.
• Dwarf peas — Bush varieties. Support with twigs. Spring and fall crop.
• Leafy Asian greens — Bok choy, tatsoi. Compact. Fast harvest.
• Edible flowers — Nasturtiums, calendula. Sell as garnishes.

What to Skip

Tomatoes need bigger pots. Corn and squash need too much space. Pole beans need tall trellises. Stick to shallow-rooted, compact crops. Our container gardening 101 covers pot size by crop.

Crop	Min Depth	Sun	Days to Harvest
Lettuce	6 in	4–6 hrs	30–45
Basil	6 in	6+ hrs	40–60
Radishes	6 in	4–6 hrs	21–30
Strawberries	6 in	6+ hrs	60+
Green onions	4 in	4+ hrs	21–30

Soil and Feeding

Use quality potting mix. Add compost. Fertilize every 2–3 weeks with liquid feed. Window boxes leach nutrients fast. Small root zones need regular feeding.

Watering Tips

Window boxes dry quickly. Wind and sun increase evaporation. Water in the morning. Soak until water runs out the bottom. Self-watering window boxes exist. Or use a drip line from an indoor spigot.

Frequently Asked Questions

How deep should a window box be for vegetables?

At least 6 inches. 8 inches is better for greens and herbs. Deeper boxes hold more soil and need less frequent watering.

What grows in a north-facing window box?

Lettuce, spinach, arugula, mint, and parsley. These tolerate 4 or fewer hours of sun.

Can window boxes hold enough soil for tomatoes?

Most window boxes are too shallow. Tomatoes need 5+ gallon pots. Use window boxes for herbs, greens, and strawberries instead.

How often do I water a window box?

Daily in summer. Check by sticking a finger in the soil. Dry an inch down? Water. Smaller boxes dry faster than large ones.