Planting in cold temperatures

Wow, it feels cold outside. This might be good, for some plants.

From what I've been reading:

Kale tastes better if it gets nipped by frost.
Spinach seeds can be sown in frozen ground.
Lettuce can be grown in temperatures as cold as 28F, but from seedlings, not from seed. Lettuce is more harmed by heat than cold, so the earlier the better.
English peas can be sown directly into the ground, in the cold.
Carrots and radishes can be sown as early as the soil can be worked.
The tallest plants should go on the north side so they don't block sun from others.

We live in Hardiness Zone 7.

It looks like I'm exactly 6 weeks out from our last frost (how they know this, I do not know). Which means it is perfect for planting kale and spinach outside, but slightly too early for other things, although if I was planting from seed I could plant things inside (this is a no go, I don't have any good sun inside!).

When I go looking for seeds and seedlings today, I'm going to look for three kinds of greens (maybe kale, turnip greens, and spinach), lettuce, peas, radishes, and carrots. I'll try for whatever combination will fill up one 8x4 raised bed. Using the square foot gardening strategy, that would be 32 different plants.

I did a search for square foot vegetable gardens. Tim in Indianapolis has charts and graphs of how he has laid his out. He includes plans for crop replacement mid-seasons, taking full advantage of the space, as well as annual crop rotation. One site encouraged the use of marigolds and nasturtiums in any vegetable garden to keep the pests away from the vegetables themselves. I remember doing this with my crabapple tree growing up as well.

I have spent the last hour watching square foot vegetable gardening videos on YouTube. I've definitely been inspired to give into my obsessiveness and make a graph of what to plant in our cold weather box, definitely think I should give into the weed cover idea, and am excited for our garden!