It's really easy to harvest these herbs. Simply pinch or clip off the leaves that you need. With basil, if you clip from the top of the plant it will encourage it to develop bushy growth from lower down on the plant. Oregano can simply be picked as you need it. Scissors work well with it. There is no special time to harvest, just pick and use as you need them. Remember, that basil is frost tender so in the fall, before frost, pick as much of the plant as you can and dry what you don't use right away. Oregano is generally a hardy perennial so it should come back again next year."