First, build the mini greenhouse.

Place the baking tray or plate on a flat surface. This is where your plants will grow.

Use the pipe cleaners, art straws or lollipop sticks to build a frame over the tray. This frame will support the 'glass' of the greenhouse.

Experiment with different materials to find the best way of making the frame. It will need to be strong enough to support the weight of the 'glass' and to protect the plants, as well as providing them with space to grow. The frame also needs to allow in as much light as possible.