Keeping Plants Alive During Vacation

Our recent trip to Osaka during a heat wave worried me because I have a bunch of tomato plants and didn't want them all to fry. We don't have anyone I can ask to come and water them, so what can I do?

I saw some advice online saying to drill holes in bottle caps and fill the clean plastic bottles with water before capping and upending them into the dirt, burying the cap enough to keep the bottle in position and leave it. I did this to a bunch of bottles and installed them after thoroughly watering my little garden the night before and morning off our departure.

I also saw something suggesting using 100% cotton rope in large containers of water, extending out to pots where the other end of the rope is buried, would also work. I set up a few of these.

The small plants were placed in our balcony sink, filled with water.

The sink worked, as well as the bottles. The rope thing did not, potentially because the 100% cotton rope from the 100 yen store might have been optimistically labelled or coated in something that prevented them being beneficial in this situation.