Review: wicks for watering while you're on holiday

I've been away on holiday twice this growing season and I needed a way of keeping the greenhouse watered. Having asked on a Facebook group and looked into a few systems I came to three conclusions:

1. Ideally you should have a neighbour who can water when you're on holiday and for whom you can return the favour when you're on holiday, but I don't. None of my current neighbours have gardens that need watering.
2. The best watering systems are complicated to set up and expensive, with no guarantee of success.
3. The simplest and cheapest methods (other than that helpful neighbour) are wicks or just leaving the plants to stand in a lot of water.

I decided to go with wicks, as my greenhouse plants aren't the sort to appreciate standing in water. In case you don't want to read this whole post, my overall conclusion was that these were adequate for short trips, but harder to set up than you'd think and prone to accidental over or under-watering. For the full story, read on...

I ordered 100 feet (i.e. about 30 metres) of self-watering wick cord for £9.99. It came all the way from China, so took a while to get here, but luckily I'd planned far enough in advance that it arrived in time for me to set everything up two days before I set off to check the system.

The wick came with instructions on how to set it up. Basically: 

• You need a container, such as a bucket, to hold the water and you run the wick from the water in your container to your plant pot, cutting the lengths you need from the single long wick they supply. 
• The higher your container is above your plant pot, the faster the water will run. 
• Ideally you should bury the end of the wick in the plant pot a little way under the soil to aid transfer.
• The wick needs to be soaked through before you do any of this to get the water flowing. 
• Also (not in the instructions, but something I found through experimenting), the nearer the plant pot is to the water receptacle, the faster the water will run, but conversely, the further away it is, the slower it will run. 
• If you need to slow the flow down, you can tie one or more knots in the wick to do this.
• If you need to deliver more water, you can use multiple wicks.

So I set my wicks up from three different containers in the greenhouse: two buckets between all my peppers and chillies and the huge tub I use for weeding for the tomatoes. Also, after I had cut the sizes I needed, but before I got them wet, I burnt the ends of each wick to stop them from fraying, as suggested in the instructions.

I automatically assumed that my tomatoes would need a lot of water delivered, so I gave them a huge container and set this up on a chair above them. The peppers got two buckets (in retrospect, 3 would have been better, but I didn't have a third bucket) and I propped the buckets up on a Pyrex dish and its lid. The Pyrex part was irrelevant, what was relevant was the fact they were a suitable size and shape for elevating my buckets. I laid out wicks to each of the pots, wetting them first, making sure they went all the way to the bottom of my water container and burying the ends of them in the soil. 

Fortunately I did all this two nights before we set off on holiday. I came back to the greenhouse in the morning only to discover that my trays of plant pots nearest the bucket were swimming in water, some to the point of overflowing, so I emptied these out and tied some knots in the worst problem areas and removed the Pyrex dish and lid from under the buckets to slow the flow.

 My tomatoes didn't seem to be getting enough water, so I added an extra wick to each tomato pot. I topped the water in the containers back up. When I came down the next morning, everything seemed to have had roughly the right amount of water delivered to it. So I topped the containers up again (the weather was very hot and my plants were thirsty) and then, with some trepidation, I set off on holiday for 4 nights. When I came back my plants had all but drained their containers.

Also, despite having some water left in each of the containers, the soil around each of the plants was much drier than when we went away on holiday, so it turned out that the rate at which water was delivered decreased as the containers emptied.

I then went away with even more trepidation for 8 nights in September, thinking that my containers would surely run out of water. They didn't - I had left them very full. But I did start out with my plants near the containers getting watered excessively at the beginning and all plants being parched of water at the end. Also, one of my tomato containers flooded while I was away (and not the one nearest to the water container either, so I don't know what I did there). An additional problem of the second time I set it up was that I had already cut the wicks to length and had to work out which one went where.

My overall conclusion is that wicks are far from an ideal watering system. They need setting up in advance and adjusting every time to get the watering levels more or less right, but even with adjustment they're not entirely reliable. They're also unlikely to be able to deliver 2 weeks' worth of water however large the containers, as if you start with that much water they're likely to flood the plants at the beginning and still leave your plants dry at the end. On the other hand, at £10 plus any cost for containers, it's a reasonable temporary solution to cover breaks of up to a few days in hot weather or slightly more than a week in milder temperatures.