Having used these for a good few weeks now, I have a few likes and dislikes to the different versions.
I have pictured the 3 common cost effective easily made options. I have decided to use option 1 for my chilli pots as they are the easiest and interlinking them limits movement of the pots as needed.
- This is the cheapest and easiest option. Likes: Just seal the hole. I used hot glue and a disc cut from an old clear food container. Bury the pot and close with the lid. Easy to fill, lift all the lids, full with a watering can and close. Easy to see the full level. Dislikes: the most evaporation due to the large exposed lid and stays the warmest, thus need to be filled more often. Least amount of soil contact. Very difficult to interlink with a water reservoir to keep full.
- This is made by hot gluing the lid to make a sealed unit. Likes: has less evaporation and cooler due to less open surface area. More soil contact surface area and easy to link up to a water reservoir. Dislikes: if not connected to a reservoir they need a small cap to stop soil falling in, and the caps are fidily to remove and a funnel is needed to fill. Can't see the full level.
- Is is made by sealing the bottom hole of 1 pot and hot gluing the top of the pots together and sealing. Likes: Double the water volume and soil contact area. Like option 2, is cool and only a small exposed area and easy to connect to a reservoir and interlink. Dislikes: are as per option 2.