7 Fast-Growing Vegetables You Can Grow Indoors, According to Horticulturists

Microgreens

Microgreens like arugula, basil, or chard can all grow quickly indoors.

“Harvest takes only one to two weeks depending on the plant,” says Maksim Kazakou, a resident botany expert at Plantum. Grow lights are helpful, but some microgreens can flourish without them.

Make sure to use high-quality seeds, and harvest as soon as true leaves appear—waiting too long slows new growth and reduces the microgreens’ big flavor. Select a shallow tray with good drainage.

• Size: 1 to 3 inches tall
• Care instructions: Bright light or grow light. Mist daily; keep soil damp.
• Time to harvest: 7 to 14 days

Onions

This vegetable is very easy to grow indoors and doesn’t require a grow light. “Place a bulb in water, securing it so only the base touches the liquid, and keep it in a sunny spot,” says Kazakou.

Change the water from time to time so the bulb stays healthy. You can harvest green onions in about two weeks.

• Size: 12 to 24 inches tall, 6 to 12 inches wide
• Care instructions: Bright light or sunny windowsill. Keep soil moist, not soaked.
• Time to harvest: 14 to 20 days

Radishes

This is another of the fastest growing vegetables that you can plant indoors, and it’s perfect for beginners.

According to Morris Hankinson, the managing director of Hopes Grove Nurseries, using loose, well-draining soil and not overcrowding seedlings will provide the plant with the best home environment.

Place the radishes in a cooler indoor spot, as they prefer colder temperatures in winter.

• Size: 6 to 8 inches tall
• Care instructions: Bright light or a grow light for 10 hours daily. Keep soil evenly moist but never soggy and overwatered.
• Time to harvest: 20 to 30 days

Spinach

These vegetables are compact, nutritious, and well-suited for indoor temperatures. While they do take more time than some other vegetables (30 to 40 days to harvest), they grow faster in cooler rooms. “Just be sure not to place them near heaters or sunny, hot windows,” says Hankinson.

• Size: 6 to 12 inches tall and wide
• Care instructions: Moderate to bright light, 10 hours per day. Consistently moist soil, but not overwatered.
• Time to harvest: 30 to 40 days

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Tomatoes

Determinate tomatoes—compact, bushy, dwarf, or early-ripening varieties and hybrids—are great for growing indoors.

Many will be ready to harvest in 90 to 95 days, but according to Kazakou, some of the “ultra-early” species ripen about 10 days sooner. Many of the dwarf varieties only need a 1.3-gal (5-liter) container to grow indoors.

• Size: 6 to 10 feet
• Care instructions: Full sun. Loamy, well-drained soil.
• Time to harvest: 90 to 95 days

Lettuce

Lettuce is quick, reliable, and ideal for cut-and-come-again harvesting. Hankinson says lettuce only needs 25 to 35 days to harvest indoors, but it needs a wide container with good drainage. It's surprisingly easy to grow but make sure to keep it near a bright window or grow light.

• Size: 6 to 12 inches tall and wide
• Care instructions: Bright indirect light or grow light 10 hours per day. Light, frequent watering to keep soil slightly moist.
• Time to harvest: 25 to 35 days

Dwarf Bush Beans

This vegetable is a surprisingly quick and productive plant when grown indoors—and when you have enough light. It only needs a light feeding every two to three weeks, so it's also relatively low maintenance.

• Size: 8 to 12 feet long, 3 to 5 feet wide
• Care instructions: Strong light or grow light 12 to 14 hours per day. Water deeply when topsoil dries.
• Time to harvest: 40 to 50 days