Anyone? Buehler?

If it's for tea you can harvest it now. But the scent is most intense if you harvest when the buds are still closed. It's easy to tell. If you can see the flowers they are open. When they're closed they are like small purple rice grains.

For drying, pick flowers just as they open, along with some of the foliage, and hang in bunches upside down in a dark, airy room. Some experts recommend harvesting when the bottom third of the flower spike is in bloom. Do not use excessive or prolonged heat if drying them artificially, as the oil is very volatile. When they are dry, rub the flower heads over a bowl to loosen them from the stem. Pick the leaves at any time for fresh use, or before flowering if drying. Small, woody black or brown oval seeds are enclosed in the tightly closed calyx.

I make lavender tea all the time. I usually try to pick the flowers before they've opened when you've got a cluster of purple bulbs on the top, but I also toss in some of the opened flowers for good measure! Remember that the leaves have just as much if not more flavour than the flowers!