Pot plant supplimenting food storage

Depending on the size of the pot something like a cherry tomato plant (vitamin c), a herb like rosemary or parsley, maybe a broccolini plant or 2 (once you harvest the initial 3 to 5 cm head it will keep sprouting for a while). Cos lettuce in the winter and other in spring etc. Shallots are a great alternative to onions. Any plant that will give a bit of yield on it. The rosemary is all year round other things are seasonal. You can always do some sprouting with something like cress (full of vitamin c) The seeds would not take up much space and it will had some greens to your diet (also handy if you cant go outside for a while).

Hmm, 2-4 plants isn't going to give you a lot of produce, whatever they are and you can store plenty of vitamins tablets without having to water them. You can store and use dried herbs easily enough, though desperate times makes even the most bland food taste good [try it if you don't believe me]. A lemon tree is a consideration for it's C, though it's size versus return to my mind doesn't warrant it.

I'd be inclined to aim for a kit with veggie, herb seeds and fertilize so that you can switch to growing and store and bring 3 months worth of food to get you to the first harvest and hope it's not winter [due to a lack you can grow and slow growth]. I'd also work on the knowledge of growing veggies perhaps in those pot plants if you can only do it that way so that you're at least a little familiar with running a veggie garden. If that was the aim, then a pot of different varieties of seed potatoes would be ideal as they can potentially [and with time] grow into a viable staple [excellent for our weather and ease of growing] thought it would take time to get to a large enough crop to survive on it. Having said that various Pumpkin seeds are also a crop you could survive on that don't require keeping some in dirt and you could transform that into a full blown crop that would give you enough KJs within 3 months, unlike potatoes that might take a couple of years to build up. There are other options also, think 'staple' food because KJs are king.

For instance, you need about 5 buckets [85 days] based on 12,000kj/day if you used 15 packets of safeway rolled oats and 5 cans of sweetened condensed milk and some vitamin tablets and a little salt.   That is 600g of rolled oats and 1/4 can of condensed milk/day.  That's 3 months.  Combine that with an extra bucket for veggie seed packet, focusing on variety and your staples as well as the rest being fertilizer.  The buckets themselves become a means of watering.  Much easier to transport, similar sizing to some pot plants. 

This does inspire me to come up with a kind of cheap-ass prepper kit along these lines. 

My first thought was cherry tomatoes and basil. Then sprouts and kale.

Have you considered hanging growbags? 



Or maybe a vertical garden?



Both could be portable(ish)

More room for pots than hangers but that's a nifty idea

Buying is awesome
My next step is another place or small property

Cherry tomatoes - there are a number of varieties that are specifically for hanging pots.
Silverbeet - easy to grow, and once you start plucking leaves, more grow.
Herbs, lots of herbs!!!
Strawberries - more for a treat!!!

Also, make sure you use a good quality potting mix, and fertiliser too!!!