No soil?

I've settled down with the idea of the little green kit. It's quite scary, considering I only have one month left til the presentation. I need to quickly make experimental trials, model, refine and then prototype more.

I've listed down the components of the design idea, and what I need to do for each:

a). Package itself / Vessel:
- explorations with forms to find a way to make package BECOMES the vessel
- material: explore suitability and availability of any bio-degradable materials

b). Greenery:
- seeds ("somehow" can be included in the package as an idea of a gift)
- locate local sources to test trial suitable types of plants to present

c). Growing medium:
- can't give the users soil: it's too freaking heavy!
- what can I use to replace soil? consultation with techs!

d). Instructions:
- This will have to wait til the package design is finalized