I thought I should share this I had with my fellow Canadian growers since it is a Canadian idea. I bought this microwave cover at Dollarama for $1.25 and drilled some holes all around and another in the center,along with a slit at the side to put the stem of plant through. Since the plastic is quite brittle it was hard to do a perfectly straight job . However as for functionality, I dont think it matters very much .
Its kind of like having a giant watering can on top of your soil with all the evenly spaced holes. It certainly helps to make sure that the pot is being watered evenly since it drains at a perfectly even rate all around. Its definitely something which could go a long way to prevent your soil from drying out in spots and becoming hygrophobic . I cant think of anything else that mimicks Mother Nature with her rainwater any more thasn this ! Also saves you from having to hold your can,or pitcher in the air for a minute or so for each plant . You can just pour the water into the strainer in about 5 seconds and let it do all the work . Not much water goes through the slit on the side compared to the water going through all the holes, so thats not an issue.
You can see it isnt quite big enough to cover the whole surface or the soil, so I just add a bit extra water around the edge of the pot to make up for it. If I decide to get these made up for sale I will make several different sizes for different pots too . The only thing you need to be careful about is to make sure the pot is on level ground so one side doesnt get more water than the other.