Spring is a terrific time for planting flowers with your children. They love tending plants and other living things and it can be fairly inexpensive. An added bonus is that this activity can give them a real sense of responsibility and accomplishment. Space and expertise are not necessary.
Container gardens are a great way to plant flowers.
You can have the pots inside or outside, they don't require weeding, and can really brighten up a home. The most important consideration is the size of the pots. Get pots large enough so you won't need to water constantly, but small enough that your children can move them around. You can also create flower pots by cutting open old milk jugs or other clean plastic containers. Remember, you should only put one plant in each pot, to allow for proper growing room.