Travelling for a few weeks and don't want your plants to dry out? Is your neighbour also unable to water them? Then try this simple solution with a wick. I have used it in my container planters but it can be used in any type of planters, even in raised beds.

Step 1: Materials

Paracord, the cheapest is also good.
A container for water with a lid. Best if it's black so that algae won't grow in it.
Aluminium foil only if you do not have a lid for the water container.

Step 2: Put in the Wick

Make a groove for the cord with your fingers. It need not be deep but the cord has to be covered with dirt so that the water won't evaporate. I'd say 2-3 cm (1 inch) deep in case you want to water on really hot days so that the dirt doesn't wash away from over the cord.

Push the cord down and cover it with dirt.

Step 3: The Water Container

Now put the other end of the cord in the water container. As you may be able to see from the picture, the cord is already wicking the few drops of water in the bottom.

Make sure the cord is long enough for the cord to lay on the bottom so that it can wick whatever water may remain in the bottom after some weeks have passed.

Now put your water container on a brick or so. As long as the water level is above the level of the wick in the ground it will be wicking 900 ml a day. After a week it will be wicking about 100 ml a day.

Step 4: Finishing

Cover the water container to prevent both evaporation and algae growth.

This easy, practically cost-free solution saved my tomato plants when I travelled for three weeks. Yes, they did look a littly thirsty when I came back but more like from lack of water in a couple of days only rather than three weeks and the tomatoes they delivered were exquisite!

Try it out before you travel as your weather and the plants' water need may be different.