Looking for opportunities to grow tree seedlings in plastic (PET) bottles, I transplanted a maple seedling (Acer pseudoplatanus) from my garden in a bottle and studied its ethology.
Growth was rather slow, but steady. It shows that young tree seedlings can easily be grown in plastic bottles. This would certainly help to reuse the bottles and thus contribute to combat environmental pollution.
Maple seedling in an inverted plastic bottle standing in a yoghurt pot. I keep the lid (stop) on the bottle and perforate the bottleneck just above the stop at two opposite sites. This is a sort of cheap self-watering system. One can also put one or two wicks through the perforations in the bottleneck to facilitate the uptake of water. (Click on the photo to enlarge it).