We bought a few little starter plants for Jack to start this Spring. We had such an amazing Saturday, that we started a little early. Most are from the dollar section at Target and the little animal pots are from the gardening section in Target. The coolest (and by far most fun for Jack) was the butterfly garden seeds. It's a mix of four different kinds of flower seeds that attract butterflies. My kid loves butterflies.
We have them on our kitchen windowsil and they have already started to grow a little. Jack likes to check them every day to make sure. We're teaching him about watering the plants and how they need sunlight. Overall, it's been a really fun little/cheap project for us to all do together.