For all budding gardeners, take photographs, starting with the first day of planting. Turn over the camera to an older child to document the garden's progress. Vary maturity dates. Show your children how to check for ripeness by rapping on a melon or looking for the last tinges of green color to vanish from a tomato. Put younger children in charge of spotting what's ready to be picked.
Older children can use a pair of sturdy kitchen scissors to harvest their crops.
By learning to plant, nurture and harvest, your children will gain an appreciation of gardens and an understanding of what can be accomplished by taking responsibility for a patch of earth.