My dirty cheap and unsafe wicking pot

Hi there!

I'd like to share with you what has become my 'go to' growing in my excessively sunny and windy terrace. In my appartment I have a long and thin terrace. As I became interested in growing, I tried to grow in pots and growing beds but the results were... meh. The substrate in the pots were too often dry as a rock, and my efforts for rehydrating the pots usually killed the plants.
There are not many sheltered spots, so I thought that I should try wicking pots. I tried to build them as instructed, but there are too many things that I don't find easily, starting with the plastic baskets. Even so, I purchased a wide pot with a reservoir and tried to modify it into a wicking pot, with awkard results.

Then I had these milk bottles in my plastic recycling bag. They are big, 2.2 litres. So, what if I could make a wicking pot with this waste?

I tried a few designs, and I'll show you what is working best for me. All that I need is a scissors and a piece of cotton.

I cut the bottle in half. Well, not exactly in the middle. The bottom half is the reservoir, the upper half is the pot. I want the pot to be slightly longer than the reservoir. After a few attempts, I found the cutting point where the pot is only 2 centimetres higher than the reservoir.

Then, I cut a drainage in the reservoir. I want it to fill at a third of the pot height, not more. More than that causes rotting problems.  Less than that, exposes the reservoir too much. The drainage has a 'V' shape, both for ease of cutting and giving some flexibility to the base, making it easier to get the pot in.

I make a small cut in the pot and I fold one side inwards, forming an indentation. This indentation forms a hole that I use for watering. The cut helps me to fold it, but I must be careful to not cut it too much, because I want the substrate separate from the watering hole.

I could use this pot as is, but some substrate would get inside the reservoir, making it easier to rot. To prevent this, a small fix is to put a small piece of cotton at the bottle mouth. Organic matter may pass through the cotton, but at least it will hold dirt and substrate inside the pot.

The bottle comes with an alluminium lid that I didn't remove completely, leaving the bottle mouth narrower. That's fine for plants I am not going to eat.

Either way, the first time the wicking pot is used, it needs to be soaked. It's unavoidable that some organic matter goes to the reservoir. I reccomend to replace the water after a couple of days, before it rots, once or twice. Thereafter, the water in the reservoir will be cleaner and less prone to rotting.

Remember that this is unsafe pot, so it's a good practice to smell the reservoir periodically: Any foul smell, remove the water in the reservoir and let it dry a little.

It's easy to forget that a wicking pot is constantly wet, as long as it has water in the reservoir. This is what makes my plants survive in the harsh conditions of the terrace. But on the other hand, the sustrate needs to dry periodically too, to prevent excessive fungal activity. I've ruined many plants with moss formed in the surface of the pot, only for watering before the substrate needed it.

I'll insist on this point: check the substrate before watering, an empty reservoir is not enough reason for watering.


All in all, I'd call it a sucess. I have killed many plants testing the system, and I accidentally still lose one or another for not observing the substrate, but now I have lots of plants surviving in my terrace in small pots, something I would have thought not possible a couple of years ago.

This seems like a very practical system - I'm glad it's working for you!  

Why do you describe it as unsafe?  The tricky balance between too wet and too dry?

Why do you describe it as unsafe?  The tricky balance between too wet and too dry?

Exactly.
In a truly wicking pot, the reservoir is always below the substrate, and the water only rises by capilarity. Here, the water level might reach one third of the pot, saturating it with water. This is unsafe because it removes the air and makes rotting roots an issue. But as long as I let the sustrate to drain now and then, it seems to be working.
There's a especially risky moment, once the reservoir is empty and before the substrate dries completely out, when I have to check regularly if I have left it draining long enough. These summer days it is so hot that I only have a window of a couple of days between an empty reservoir and a completely dry pot. No wonder they all died before I started using these kind of pots.
Oh, it helps inmensely if the plant is draught resistant, so it doesn't die in case that the sustrate dries out completely. Refilling the reservoir is usually enough, since the water will rise by gravity, not capilarity.