Experimenting with concrete planters

A few months back a video started making the rounds showing how to make concrete dragon eggs. You can watch the video Here.  The video used them as candle holders.  Being keen on experiments that weekend out came the plaster-of-paris and the balloons, yes sadly we have both lieing aroud the house. The plaster ones came out really easily with only minor modifications of havig to turn the eggs constantly for about 10 minutes then leaving for about 30 minutes.

A few more were made and have been put aside ready to invite one my newphews around to decorate.

While they would make excellent candle holders my first thought was always as planters, especially if the concrete worked.  So a trip to the hardware shop to buy some quick drying concrete and time to try my first concrete egg.  It looks so easy on the film: mix the concrete with water, pour into balloon, turn every two minutes for 2 hours.  I ended up with a lump of concrete.

Four attempts later

I have watched several different videos now and they all simply say, turn every two minutes. I don't know if I am usig different cement, but it just doesn't work for me.  Instead I have found shaking, then turning, then shaking, then turning. The reason for the shaking is that if the concrete hardens giving the ballon a good shake softens it again, giving you another go.

Tip: leave the eggs for at least 12 hours to harden before bursting the balloon.  Again after only 2 hours it was no where near enough, and even after 6 or 7 if the concrete was too thin, the egg just crumbled.

Now the big warning.  Do not do this inside, especially not in your best room, while sitting on your new furniture with you OH and the dog.  Yes sadly I do speak from experience and amazingly I am still married and alive!  We both wish we had taken a photos, as it went everywhere.  I'm not sure if you have ever tried bursting a balloon filled with water, but shaking and then looked at how far it spreds.  It is very effective, the carpet, walls, furniture, pets and us all covered.

So lesson learnt.  In fact I found puttting the ballon in a plastic bag saved a lot of mess should things go wrong when popping the ballon as well. 

Once you have the eggs, you can make holes.  Again the video makes it look easy, but make your egg too thin and the slightest pressure and they crumble.  I have a nice collection of concrete bits in a bin in the greenhouse.  My tip here would be to leave the egg for 24 hours to let it harden a bit more, and to check it over for cracks so you know the weak points.

Then you can reinforce it. This was probably the easiest bit, mix some vert liquick concrete mix, pour it into the egg and swivle it around to coat the inside. You do have to keep an eye on cracks don't be tempted to over do it the first time. It was better to do three layers, leaving the layers to dry between.  The first layer is the crucial one, especially while turning the egg as it's easy to crush it.

While doing all of this I tried adding different coloured powder to the concrete to colour the eggs.  The red looks great when wet, but is very pale dry.

Black probably has the most promise.  This was the last egg I tried and is the most sucesfull.  I learnt that blowing the ballon up and leaving it blown up until you are ready to pour the concrete in allows you to get more in and so to have thicker walls.

I am toying with differet ways to finish them.  The first few were soaked in water for a couple of weeks, changing the water every day.  This should help leach out some of the stuff plants do not like.  The other options are concrete sealer, and painting.

Then you can drill drainage holes and plant them up.

I've got a few more to plant up, I'll save them for another post.  I'm probably going to try a few differet plants for differet parts of the garden. They probably lend themselves more to the clump forming plants than the agaves, but I'll have to try one with an agave in. I think they would be great with a mound forming succulent flowing over the egg.

Now go away and try them for yourselves and show me how you would plant them up.