September is a great time to plant vegetables and herbs that thrive in cooler temperatures. Here are some vegetables and herbs you can plant in September according to the search results:

• Lettuce: With good soil, lettuce can thrive during the autumn season. This fast-growing vegetable, especially baby lettuce, can be ready to harvest in just about 30 days from sowing.

• Spinach: Spinach is a great vegetable to plant in September. It can be sown on bare soil and does best in cool, moist conditions. It can be harvested in around six weeks.

• Arugula: Arugula is a leafy green that can be planted in September in the northern US, Midwest, and southern Canada.

• Collard greens: Collard greens are another leafy green that can be planted in September in the northern US, Midwest, and southern Canada.

• Kale: Kale is a hardy vegetable that can be planted in September in some regions.

• Peas: Peas can be planted in September in some regions.

• Radishes: Radishes are a root crop that can be planted in September in some regions.

• Carrots: Carrots are a cool-season crop that can be planted in September in some regions.

• Garlic: Garlic is a root crop that can be planted in September in some regions.

• Onions: Onion sets can be planted in autumn for an earlier crop the following spring and summer.

Its important to reference the USDA Hardiness Zone map to determine which plants are likely to grow successfully based on your location.