If you garden on a balcony where the rain never reaches, going on holiday means you have to find some way of getting water to the plants when you're gone. There are lots of possibilities - get a plant sitter, buy those special gels that dissolve into the soil providing moisture, get an automatic watering system - but they've all got disadvantages.
Plant sitters first of all. Unless they're really gardeners, they tend to overwater - so you come back to drowned plants sitting in saucers of water. I know - I've tried that one. And unless they're friends or relatives who you can do the same for while they're away, you have to pay them. And that can work out expensive.
So do the gels. They work - I've used them in the past. But at €3 a tub, they're really only an option if you have the odd houseplant. I worked out that I'd need seventy of them to do the whole balcony...
Then there are those systems where you have a water container with capillary matting or tubes running into the pots. Again, less feasible if you have a lot of plants spread out over three long balconies as I do.
Then this year I found these. Ceramic spikes that fit into an ordinary mineral water bottle. Turn them upside down and the water slowly permeates through. I bought a couple, and they do work - on my "test run" I gave the plants no other water for ten days, with temperatures between 25-30°C (77-86°F) each day. They were fine, and the bottle was still a third full at the end. So they could easily have gone on for a fortnight.
But again they're hideously expensive - €7 for two, and I needed seventy. So I tried Amazon and found something similar (though not quite so classy). Plastic spikes that release the water drip by drip.
They're still not giving them away. But unlike the gels, you've only got to buy them once, and can reuse them again and again. Which means that the initial outlay is a bit less painful to contemplate.
The only real disadvantage if you want to use them in quantity, is that you have to save and store bottles for months before you leave. We were getting to the point that every time you opened a cupboard a score of plastic bottles would fall out...
When I went on holiday, the balcony looked as if I was running a bottle farm. But who cares - I wasn't there to look at it.
If you want to try them...