Teach your preschoolers that zucchini starts with the letter "Z." Before picking the zucchini, hand out a worksheet with the letter "Z" and a photography of a zucchini for the children to color. When harvesting the zucchini, have the students place a sticker of the letter "Z" on the zucchini they pick to reinforce the lesson.
Zucchini can be either yellow or green. Review both colors before going to harvest the vegetable. Depending on what has been grown, color activities can vary. If both yellow and green varieties are present, having the children sort the zucchini into different bags according to color can be a good color recognition activity. If a green variety has been grown, having children put their zucchini into a green bag reinforces the color lesson as does placing yellow zucchini into yellow bags. Also have children point out surrounding items in nature that might also match the zucchini's color. For example, green leaves or grass match the zucchini's green color as the yellow sun matches the yellow variety.
Enforce the basics of counting, by assigning the children a certain number of zucchini to pick. Each child may be told to pick three or four zucchini before they are to stop picking. When each child is finished harvesting, point and count to the number of zucchini in their bags to reiterate the counting lesson.
After all of the students are finished harvesting, ask each student to select the largest zucchini he picked, then the next biggest and finally the smallest. This activity reinforces the concept of size and shape. You also may weigh and chart all the zucchini to find who had the biggest and smallest crop.
Leave one piece of zucchini is a clear plastic for students to observe in the classroom. The children will observe the changes the zucchini undergoes as it decomposes. Have students keep a daily journal of how the zucchini has changed.