Plants in a greenhouse

Holiday watering solutions- keeping your greenhouse green


My greenhouse is my pride and joy. This is the first year I have had one, so it’s all very new to me. It’s a very steep learning curve! I have so many questions and I’m having to learn the answers the hard way.

For instance, how do you water your plants when you are on holiday?

Early in the season it isn’t so bad. The weather isn’t too hot, and the plants are small and not too thirsty. But come June, July, August, those cucumbers are gulping up every drop and the tomatoes threaten to wilt when you so much as blink. Even if it’s just for a weekend, like when we went camping at Penwarne we came back to some fairly thirsty plants!

Those of you lucky enough to have neighbours happy to help may be feeling rather smug now. But you haven’t got off completely.

Because it isn’t as simple as handing over the watering can and leaving them to it, you’ll come back to bitter cukes and split tomatoes. Many green house plants are reliant on three things;

  • Getting enough water
  • Being watered consistently
  • Not being over watered

So lovely Julie down the road who pops over and splashes water about might be keeping your plants alive, but unless she’s pretty committed she won’t be able to keep them to the standard you need for them to bring decent crops to the table.

And that’s not even getting started on humidity, diseases, ventilation and artificial pollination. Or as I found this morning, essential greenhouse maintenance also includes shooing frightened little sparrows out who get confused because they can’t see the glass and don’t remember how they got stuck between the chillies in the first place. But let’s leave that all aside and focus on watering.

There’s a bunch of products available that claim to be the solution to your holiday watering woes. I have also tried some home made diy tricks that are much cheaper. It has been interesting testing and there are some interesting results.

I already had one system set up on six of the plants in the greenhouse.

The Halo

Sounds almost angelic.

There are a few different halo systems, all have a similar way of working. They consist of a ring shaped reservoir that sits around the bottom of the plant. The ring feeds water into several spikes that are sunk into the soil. You set up the ring in the grow bag before you put your plants in, then plant into the space formed by the ring. This means your plants are planted above the growbag so that they have a bit more compost to grow into. They often also have places you can fit canes into to help support the plants, and a clip to hold the canes together at the top.

The advantages of this system:

  • The water is let through to the plant at a steady rate
  • You can put a lot of water into the reservoir
  • The cane supports are brilliant for when your cucumbers and melons are threatening to take over and flopping around everywhere.

The main problem with this is that even with the extra large Tomorite growbags I bought, you can only get two halos into each bag. There just isn’t enough space to get three. So two of your plants are beautifully watered and supported, the third in the middle less so.


Other drawbacks:

  • They don’t hold enough water to keep the plants going for a long time, at least not in mid summer.
  • They are really expensive.
  • You have to have the forethought to put them on before you get growing.

Looking at the last point there, I had only put the halos on a few of my plants, so I had to come up with something to keep the rest of the greenhouse alive.

Next let’s look at the cheap DIY option.

DIY cheap Ziplock holiday watering system

Having spent all my spare cash on a greenhouse and a shed load of compost, I didn’t like the prices of commercial holiday watering products. So I had a go at making one myself.

The concept is simple. You need:

  • A ziplock bag
  • Cotton or nylon thread at least 20cm long
  • A very fine needle
  • A super steady hand
  1. Take the ziplock bag and open it out.
  2. Thread the needle and tie a knot in the end of the thread. It needs to be a really big, chunky knot. Make sure it is just one big knot, not a series of little bumps.
  3. Taking care not to make any rips or holes in the side of the bag, put the needle inside the bag and then push it and the thread through the bottom of the bag. This should leave the knot on the inside of the bag and a long tail of thread outside. Don’t push the thread too hard, you want as small a hole as possible. Remove the needle.
  4. Fill the bag with water and seal the zip. Watch out, now it will start dripping!
  5. Put the bag next to the plant you want it to water. Make sure the hole and thread are over the soil that needs watering. Cover the thread with a little soil.
  6. When you are about to give up as my directions are too complicated, check out this great instructibles.

Tada! Now through the science that is capillary action the water should very slowly work its way down the thread and into the soil, watering your plants for several days. All for pennies.

Sounds awesome, right? It is, and it does kind of work. But it is tricky to get right.

  • If you made too big a hole the water will just leak out and you’ll end up with an over watered plant that will then dry out over the next few days.
  • If you made too small a hole then not enough water will come out, and you’ll come back from holiday to find dried out plants and bags still full of water.
  • Balancing the bags is really tricky! They need to stand up and not fall off the plant pot or grow bag. As the water leaks out and the bag collapses they can also create little pockets of water that then never makes it way out of the bag. I used half a packet of wooden skewers trying to prop them up.

Did I mention I was doing all this testing the week before I went on holiday for a fortnight? Yep, this was more stressful than I had expected! I experimented with the ziplock bags for about four days before I decided that they would help, but were not reliable to be trusted for a fortnight. (How right I was! I came back to find only half had actually emptied, the rest were sitting still full of water!)

So having exhausted my DIY ideas, I turned to Amazon.

In my panic I bought two kinds of “holiday watering solution spikes”. Thank goodness I did.

Caraselle Watering Spikes

The concept is simple. You take a plastic bottle and make a very small hole in the bottom. Fill the bottle with water and screw the spike on where the cap would normally go. Shove the spike in the soil by the plant.

Then watch as the water pours out of the bottle in about three minutes.

Awesome. Now you have a waterlogged plant and no clue how watering your plant for the other 20157 minutes of your holiday.

So I read the instructions a bit more carefully and apparently you must stuff kitchen paper into the spike to slow the water flow. This mostly works, but it is tricky getting the right amount of paper in and squish it up just right so that you get the slow and steady flow you need.

They might work really well if you have the time and patience to fine tune them, but I didn’t. They might also be great for plants you want to regularly bottom feed to encourage deep rooting.

The next day another batch of spikes arrived.

Selections GFA825 Plant Bottle Top Watering Spike

These function much the same way as the other spikes, but with the great improvement of having a screw turn adjuster so you can set the flow rate without fiddling around with soggy paper.

Yay! No more flooded plants! A perfect slow drip.


That’s not to say these are perfect or faff-free.

  • Only certain bottles fit the screw top. I used tonic water 1l bottles.
    It’s tricky filling up the bottles as the water squirts out the hole you punched in the bottom.
  • Growbags and spikes are not a great combo, you’ve got to be really careful you don’t make a hole in the bag.
  • You are limited on how long the system will water your plants based on how large a bottle you can use.

IMG_4831The results

I had a lovely holiday. I tried to forget the impending green house desert dust bowl disaster that I was sure I would return home to.

I had done everything I could. I used a mix of spikes and ziplock bags, filled the halos up to the brim and bribed my neighbour to come and splash water about liberally in return for as many sweet peas as she could carry.

It was, inevitably, a heatwave. I got fabulously sunburnt while hoping my plants weren’t getting scorched too.

Somehow they were all still alive when I got back. The tomatoes at the front had taken the worst of the heat and were a bit dry and wilted, but with a gradual soaking over the next few days they perked right up.

Half the ziplock bags had emptied perfectly. The other half sat full and somehow had sealed themselves up. Some water must have leaked out of all of them as when I lifted them they revealed a new and intricate lacework of roots.

All the spikes had emptied well, as had the halos. It was impossible to tell if they had emptied in the first half hour, or had kept up a slow rate the whole holiday. Luckily my neighbour really likes sweet peas and she had kept everything alive even where my best efforts to provide water had failed.

I’m now trying to get a tube and drip system set up that will run off my water butt. At the moment it is sitting in pieces on the table. Fingers crossed this will work better and mean I’m not so reliant on the old fashioned way of watering- the good old watering can.

How do you keep your plants happy and watered while you are on holiday? Do you have the perfect system set up?

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