Tip I find bottles with a tapered end easier to position in the pot.
500 ml is perfect for 4.5" diameter pots. For larger pots use a 1000 ml bottle, and for bigger pots Plastic milk containers make a handy reservoir. The containers must be plastic so they are able to collapse as the water is used up.
2. Make sure to water all the plants first, then fill up each bottle to the top.
Stretch cling film over the top of the bottle and secure with an elastic band. Make ONE small hole with a medium sized needle in the centre of the cling film.
|An ideal tapered bottle|
|Stretch the cling film across the top of the bottle and fix in place with an elastic band|
|Make one small hole in the centre of the cling film with a medium sized sewing needle.|
3. Invert and press firmly into plant pot. Secure with a stick if necessary. The water from the bottle will seep out as the soil in the pot looses moisture.
|A newly inserted bottle.|
|A bottle that has been in place 6 weeks.|
In the second image the reservoir has been in place 6 weeks, the bottle has collapsed as the water is being sucked into the soil.
It is best to set up the watering system a week or so in advance to monitor it. My plants have been left for up to 3 weeks in the winter and summer and survived perfectly well.
If you want to buy ready made reservoirs there are some nice ones to buy.