Hi Pam, I know you can use the green seedheads in pickled gherkins..., I also use it in potato/leek soup
You can use dill seeds as you would the leaves, just use less as they are stronger in flavour. My favourite salad is cooked grated beetroot, chopped onion, S+P, vinegar oil and either fresh dill or dill seeds and some fresh parsely. Stores for quite a while in the fridge.
In fact in general beetroot and dill go very well together