Hey Virginia,
to ATP!
I can't imagine why you shouldn't plant bulbs under your salad greens etc. Sounds like a fine idea to me.
The bulbs are fairly deep down, 4 or 5in. if you're talking about tulips and daffodils that is. So they won't rob the salad greens of nutrients while they grow, bloom and ripen off their foliage. The lettuce, garlic and shallots have all their roots in the top 2in. or so of soil. Probably not a good idea with root crops like carrots or beets, though. They go deeper.
Just be very careful if you're planting greens in the early spring not to nick the tips of the emerging bulbs as you prepare your soil. Maybe mark where you plant each bulb with a little stick or something? Just so you know where they are before they pop up.
