There are lots of YouTube guides on how to make an SIP out of discarded PET Bottles. Many of them make use of 2 Litre Bottles, particularly “Family Size Coke Bottles”. But they are not common in this region (we don’t drink so much Coke!). 1.5 Litre Bottles are more easily available. Every weekend I never fail to find boxes of these at the Recycle Bin Area where I live.
The best bottles to use are Mineral Water Bottles – they are clean and you don’t need to waste tap water to wash them out. (BTW, I use ONLY rain water to wash anything related to gardening. More on rainwater harvesting in another post…soon)
I have been experimenting with the use of 2 x 1.5 litre bottles since 2010. The best bottles to use are those with a straight / constant profile. Better still with corrugated edges as these will help to “lock” the 2 bottles together. Examples of such bottles are those under Giant, Tesco or EconSave.
Get 2 x 1.5 Litre PET bottles and 2 fat straws (eg those used for bubble tea, chendol etc). All you need is a good pair of scissors to cut the bottles based on the pictorial information on the right. Feel free to modify and improve the configuration.
Once you have assembled the parts together, add LECA (Lightweight Expandable Clay Aggregates) to the bottom. This is an excellent wicking material to get the water up to your potting mix which you fill to the top. Finally, wrap it around with the aluminium foil which you can get from DIASO. This prevents light from getting into the bottle so that there won’t be algae growth. Also, the roots don’t like light.
A note of caution, do wear safety gloves as there have been incidences of participants accidentally hurting themselves during some of my workshops.
After making several of these PET Bottle SIPs, you will need to find a place to hold them. The most cost effective is to use plastic / aluminium shoe racks. You can adjust the height of each shelf to allow for maximum lighting or spacing between plants.
Note that I have drainage pipes and bottles to collect overflow water. Drainage and water storage is a big topic itself for another post. Meanwhile have fun building your own PET Bottle SIPs