My peppers, etc, are already sowed and growing well, in a seed tray on a windowsill. I find sowing stuff in the ground (potates aside) is usually a poor strategy, though that's maybe because I have a soil whose surface dries out very easily and shallow planted seeds are hard to keep moist enough for good germination. Stuff only goes in the ground straightaway if it really is a no-disturbance crop (and carrots would be a disaster in my soil anyway). For your potatoes, try putting some black plastic out so that when the sun does reappear it will warm up the soil quickly for you to put your potatoes in without too much delay.