Well Simpson and Red Sails seem to be well liked all around. That's a good sign for me
Kale....well, isn't kale really bitter? I am growing bright lights swiss chard this year. I'm not sure if I'll like it, but if I don't it makes a very pretty ornamental
I LOVE spinach, but I've never grown it. I'm leaning toward Regatta spinach as I've heard it's good as baby leaves or full grown.
How much lettuce would you plant to have a decent sized salad every other day or so? And as far as succession planting, every week? Two? Oh, and I have to provide enough for preschooler nibbling. My little guy will be 3 1/2 this summer and he can mow down salad with the best!
Personally, I don't find Kale bitter but others may. It definitely isn't as bitter as some of the bitter greens or as strong tasting as the arugula I'm now growing.
One thing I'll do with kale once in a while is pick the leaves, wash and dry them, break them up a bit in large pieces, sprinkle with olive oil and mix to coat well, add some sea salt, black pepper and place in a 275 degree oven spread out in a pan to dry out to just crispy. This makes for an interesting snack similar to chips but much healthier.
I now have at least 75 ft. of rows devoted to all of my salad and cooking greens. I've only done 3 plantings, all direct sown into the garden since late September and will likely get some started in trays in a week or so to put in for spring since I doubt seriously the seeds will sprout in these cooler temps.
It's great that the youngster likes salads. I too loved salads as a kid and can survive on them if the need arises. Oh, and spinach is no harder to grow than many other salad greens. The only advice I can give on salad greens is they grow well in cool/cold weather but tend to bolt quickly when it is warm. So, to extend the season a bit, plant them in an area where they will receive some shade during the hottest part of the day. I grow mine near my pole bean trellis and it is shaded from the evening sun. That only works for so long though in our summer heat.