Many plants, like basil and some lettuces, are ready to begin harvesting at 2-3 weeks.  With  basil, prune the top growth off plants at the leaf nodes to encourage bushier growth, and to keep fast-growing basil from overwhelming your garden.  With lettuces, harvesting the larger leaves early delivers more light to more leaves, increasing your overall harvest.  While yields at this point will be dwarfed by later harvests, your garden will be healthier because you did it and the small early harvests are easy to add to soups, salads and sandwiches for a great taste treat.  Don't delay, harvest today!