I had an idea of sorts for food production and was wondering what you lot thought of it.  A long small diameter pole could be used as a sort of mini spar.  A floating platform can be raised and lowered to and from sea level by winch meaning you could board it for planting, harvesting, and general maintanence.  This would make the weight limit much lower and the  production cost of such a platformed spar very low.  Hell a person with a weekend and several lengths of pvc pipe could probably p-o-c it in a pool, lake, or pond.

Also, a cage could be winched to lower into water to provide several forms of aquaculture as well.  Mussels are already raised with similar systems and I daresay some fish could be done this way as well.  You could probably use them for water collection, power generation, wireless relay posts, and other such utilities as well.

Such satellite steads could conceivably be produced for just a few hundred USD and would provide a nice source of extra surface area to help aid in increased self-sufficiency.