Self Watering Polystyrene Box – Day 31 – Aug 3 by Thomas Wagner Nielsen | Posted on February 17, 2020 | Leave a comment Related Posts:Self Watering Polystyrene Box – Day 94 – Oct 5Self Watering Polystyrene Box – Day 95 – Oct 6Self Watering Polystyrene Box – Day 154 – Dec 4, 2019Self-watering Polystyrene Box for Tomato PlantsSetting up Two Self-watering BoxesSelf-watering Boxes vs. Pots