If you're looking to fill your outdoor plant boxes with vibrant greenery in no time, choosing fast-growing plants is the key. Here are some top picks that thrive in plant boxes and grow quickly:

1. Sweet Alyssum – This low-growing annual produces fragrant white or purple flowers and spreads rapidly, perfect for edging plant boxes.

2. Nasturtiums – With bright blooms and edible leaves, nasturtiums grow fast and add a pop of color.

3. Marigolds – These hardy flowers sprout quickly and repel pests, making them ideal for outdoor boxes.

4. Lettuce & Spinach – Fast-growing leafy greens like lettuce and spinach are great for edible plant boxes.

5. Creeping Thyme – A quick-spreading herb that forms a dense mat, ideal for cascading over box edges.

For best results, ensure your plant boxes have good drainage and receive adequate sunlight. Regular watering and light fertilization will help these plants flourish. Whether you're a beginner or a seasoned gardener, these fast-growing options will give you a lush, thriving garden in weeks!