Add a layer of cured compost on top of the chinampas and plant your seeds or plants. It's okay if a little compost falls into the water. I planted mint and parsley in this garden. When it takes off, the entire platform will be covered. See my little fishy statue? I put it there for decoration.
This garden is 3 foot square. I want to make an Aztec garden with straw instead of palm fronds. If I built another garden, I would make an edge around the sides to keep the soil boxed in. The traditional Aztec garden, however, is flat and much larger than this one. Instead of using the hemp twine, I would use a hemp net that I saw in the garden center.
See the plastic and PVC pipe in the picture? This is the cold frame that I made to keep the pond safe from frost... which is another one of my instructables.
Please see more of my how-to's and videos at www.pondplantgirl.com/howto.htm