Hold up a plant seed for the children to view. Ask children what happens when that seed is placed in the soil and given water and sunlight. The students will tell you that the seed grows. Explain that when the seed first sprouts it is called a seedling. This is the second stage of the plant's life cycle.
Explain to the students that the seedling continues to grow until it sprouts some buds. This is the third stage of the life cycle. Hold up a plant that not only has a few buds, but also has a flower. Tell the children that this is an adult plant.
Show the children the fruit within the adult flower and let them know that the fruit contains new seeds that will start the plant life cycle all over again when the seeds fall to the ground.
Distribute a plant life cycle worksheet (see Resources) for children to color. The pictures will reinforce the lesson while providing children with a visual of the entire process.
Read the children either "The Seasons of Arnold's Apple Tree" by Gail Gibbons, or "The Life Cycle of a Sunflower" by Tagliaferro and Linda. This will give the students a specific example of a plant life cycle in action.
Hand out a plastic cup, a seed and a handful of soil to each student. Have the students plant their seed, water it and set it near the classroom window. The students will be able to watch the life cycle of a plant in action over the course of several months.