Which plants do ok with minimal watering?

Strangely enough, lettuce in all its varieties, seems to do well on our plot, which only has a rainwater collection tank, so at this time of year, no water. You will need to get fruit bushes and trees established for a season before they can stand a bit of drought. Is there any possibility of rigging up a rainwater butt anywhere? On a shed or something?

It is possible to grow veg and I'd imagine fruit with little or no extra watering - this is for the most part how people managed before pipes and taps. It's all pretty much down to the spacing of your plants. In an intensive planting system (square foot gardening for example) it is to be expected that the plants will need watering in dry weather. By increasing the spacing between plants the root systems have a bigger area to draw moisture from and any moisture is not so readily sucked up by the many plants that could be planted in an intensive growing system.

Some of the natives in North America grew in a very dry environment and over centuries pioneered the art of "dry gardening". For example they would plant some seeds in a fertile hill or mound which was perhaps 4-5 foot apart in each direction from other growing stations thinning down to all but the healthiest plant. They would never give the plant any water and would rely purely on any rainfall if any. Because the plant had such a large area to draw on and no competition for the moisture in the ground it would then have a very high level of drought resistance.

There's a book I read "Gardening when it counts" by Steve Solomon which has a chapter all about watering and not watering. It has suggested spacing’s for dry gardening which I would definitely use if I was growing back in London. It would probably mean you would never have to water once any transplants were established and you'd still get really good crops. In the book he reckons your total harvest is a bit less than with irrigated crops but the wider spacing gives bigger plants and heavier crops on those plants.

You certainly wouldn't have to worry about getting anyone in to water if you went away on holiday for 2 or 3 weeks.

Try doing some research on desert gardening, there's a lot on youtube like this one: YouTube - ‪Growing Food in the Desert - Winter Vegetable Garden in Las Vegas‬‏

From Gaia's Gardening (which I love) are these tips, just quickly in bullet points

- use shade to protect your plants from scorching sun (not always nec. in the UK)
- make shelter belts to protect plants from dessicating winds
- dig swales to harvest rainwater
- incorporate lots of manure & well rotted compost to improve the soil to retain water

Once you've set up the best conditions, you can grow almost anything. When I moved house I had to abandon my lotty for weeks at a time. Crops like broad beans were stunted without regular watering, but I still got a crop. Native Americans grew French (actually they're from S.America) beans too in dry conditions. I allowed (accidentally) my onions to get covered in chickweed and I had the best onion crop ever: the chickweed shaded the soil, conserving moisture for the onions