Patriot's Day weekend is a terrific time to plant the bulk of the spring seeds and seedlings (at least, here in Massachusetts). We were fortunate to have fantastic weather, and a 57.5° soil temperature.
We planted seeds of Arugula, Bok Choy, Carrots (a rainbow of varieties), Collards, Kale (green & dinosaur), Leeks, Mizuna, Mustard, Onions (red, white & yellow), Radishes, Scallions, Swiss Chard and Turnips (salad & cross types).
We also planted seedlings of Broccoli, Cabbage (green & red) and Spinach. Cauliflower seedlings would have been planted as well, but they weren't yet available from our local farm supplier.