In Zone 7b, Hardy Vegetables Can Be Planted Outside on February 15.
- lettuce – all types
- broccoli, cabbage, cauliflower, kale
[I live inZone 7b; and I predict my average last frost date to be about April 1. Therefore, I’ll sow my moderately hardy vegetable seeds outside on March 13–My Birthday].
- carrots, parsnips, turnips, rutabagas, and beetroot
- celery, chard, swiss chard, parsley
- raspberries and blackberries
Frost sensitive vegetables should be planted on the average day of last frost. While tomatoes are normally planted indoors ahead of last frost, beans and corn are planted outdoors. Monitor weather forecasts for late frosts and protect growing plants in this group. If you live in a cool climate you may need to provide protection to grow these and the next group of crops.
In Zone 7b, that is about April 1.
- bush beans, pole beans, edamame
Frost Intolerant Vegetables and Fruits – plant fourth
Frost intolerant vegetables and fruits are the most sensitive group. They require heat and need to be planted 2-3 weeks after the date the last frost is expected. For cooler climates and shorter growing seasons some of these can be grown under cover; others are not practical.
Planting Dates from http://backyardheirloomseeds.net/how-tos/when-to-plant-seeds/