So far, my lazy method of garden-making seems to be working: covering the joint in four or five inches of compost without taking off the sod first. But kids, don't try this at home. The sod was already miserable in my sandy soil. I'd never be so cavalier in a spot with healthy grass.
I planted a few dahlias yesterday shovel-deep and saw that the buried grass is already nearly dead.
But gardening never allows for complacency. So far in this two week-old garden, I've lost pepper, basil, and watermelon seedings to cut worms. A new problem for me. In theory, after the seedlings get slightly bigger, their stems will be less delicious and less subject to a summary chomping off.
I'll have to figure out how serious this problem really is, whether it's attached to my city compost, which I probably won't be using every year, and whether to dress every seedling in a collar next spring. Of course, that doesn't work for things started from seed!