Creating a space garden in outdoor plant boxes is an exciting frontier for sustainable living beyond Earth. The best plants for these environments must thrive in controlled conditions, resist microgravity effects, and provide nutritional or aesthetic value. Here are the top choices:

1. Lettuce (Lactuca sativa) – Fast-growing and nutrient-rich, lettuce has been successfully cultivated on the International Space Station (ISS). Its shallow roots make it ideal for compact plant boxes.

2. Radishes (Raphanus sativus) – These hardy vegetables grow quickly and require minimal space, making them perfect for space gardens. Their edible roots and leaves add versatility.

3. Dwarf Tomatoes (Solanum lycopersicum) – Compact tomato varieties, like 'Micro-Tom,' produce fruit in small spaces and can adapt to artificial lighting.

4. Herbs (Basil, Cilantro, Mint) – Aromatic herbs are easy to grow, enhance meals, and improve air quality—essential for confined space habitats.

5. Wheatgrass (Triticum aestivum) – A superfood packed with nutrients, wheatgrass can be grown hydroponically and harvested repeatedly.

For optimal growth, use LED grow lights, hydroponic systems, and ensure proper ventilation. These plants not only sustain astronauts but also boost morale with greenery in sterile environments.

Future space colonies will rely on such gardens for food security and psychological well-being. Start planning your extraterrestrial garden today!