Tertill tackles the biggest challenge with organic gardening: weeds. Tertill’s weeding robot chops down weeds and prevents new ones from growing in their place. In spite of its small size, the Tertill weeding robot can maintain up to 200 square feet of garden space. The best part is that you don’t need to charge it: the Tertill runs on 100% solar energy for 1 to 2 hours a day.