This craft project was a bit of a fail. Not because I am unhappy with the finished product, but because it failed to hold the attention of my four year old, and I ended up doing most of it on my own. I guess I got a bit over ambitious on this one, so I would recommend trying this with kids older than four.
Things you will need:

Bamboo tray -relatively inexpensive, purchased from The Warehouse
Old magazines – gardening magazines are best source of flower images
Mod podge – decoupage sealer, glue and finish – I got the kids washable kind
Mod podge clear acrylic sealer
Scissors
Paint brush or sponge
Instructions:

You can often pick up second hand magazines in bulk for next to nothing, so you don’t have to pay new prices. Go through them and cut out all the images of flowers you can find. I was quite meticulous in cutting around the petals of the flowers, but you could cut out squares, circles or leave a margin around the images if you like. For that matter you could use any type of image or photo that take your fancy. Only your creativity limits you really.
Do trial run at laying out the flowers before gluing them on. This ensures you have enough images to complete the project, and it will also help you to settle on how you want to arrange them.
Apply mod podge to the tray, and place flowers on top, smoothing them down with a paint brush and more mod podge. Continue until the tray is covered and you are happy with how it looks. Leave to dry. You can apply additional layers of mod podge on top to smooth out the surface of the tray. Leave to dry again. Apply a few coats of acrylic sealer spray to finish. Leave 15 minutes between coats to dry.

What the kids can do:
Cutting out the images: This will depend on the child’s scissor skills. My 4 year old only cut out a few flowers before losing interest. If the edges are a bit wonky these can be hidden under other images.
Arranging and gluing the flowers: Kids can help with this one, but again my 4 year old lost interest quite quickly. She did help me with some additional top coats of mod podge.