Tony, You can but you may be taking a slight chance. UK pub ID-128, Home Vegetable Gardening in KY, lists March 20 as the earliest safe planting date. But years differ so sometimes this is too early and sometimes not early enough. Problem is, you won't know until weeks later. IF the soil stays warm and we don't have a hard cold spell you'll likely be ok. Kale can withstand some freezing temperatures, more so once mature and actually enhances the flavors. Spinach is more hardy and can be panted after March 1st. Good luck!