Last year I used a lot of self watering pots for growing vegetables. They consist of 2 parts the water cell which is below and the soil which is above. They work using the capillary action of the soil.
Here is a quick run through of how to build them, I hope you can understand this.
I use 20L drums to build my pots. Many business throw these away, but be sure to check what had been kept in them previously and always triple rinse them!
The first step is to saw off the top of the drum and the handle. There is a convenient line around the top for this.
Next a hole needs to be drilled near the base for the overflow, my drum has a space where the tap is normally located.
Next a piece of Styrofoam needs to be fitted into the base of the pot. My pot has a little ridge that the styrofoam can snugly sit in. (see image above) Be sure to have at least 4 or 5 holes poked through the styrofoam for drainage and for the roots to gain access to the water cell.
Needed next is a piece of off-cut pvc pipe that is long enough to touch the bottom of the pot and high enough to meet the top of the Styrofoam. Place the pipe onto the styrofoam and trace around it. Then using a sharp knife cut a hole in the foam.
Drill holes into the piece of pvc so it looks like Swiss cheese. This is rather difficult to do as the drill bit tends to grab the pipe. Then fit the pipe into the hole cut in the foam. This is the part were the soil touches the water.
An optional extra is to put in a watering pipe, however I have found they block up after awhile. It too is inserted through the foam into the water cell.
Next fill the pvc pipe with soil. Pack this down firmly, but not too hard as the water won’t be able to move up through the soil (this is capillary action). Fill the pot with soil.
Now your self watering pot is ready for planting. Water well.
The plants will need consistent watering until they become established, always check the soil for moisture levels.