Functionality and efficacy of Franklin Robotics’ Tertill™ robotic weeder

              Johnny Sanchez and Eric Gallandt

Graduate Research Assistant in Ecology and Environmental Sciences, University of Maine, Orono, ME, USA; Professor of Weed Ecology, University of Maine, Orono, ME, USA

[Published in Weed Technology August 2020]

Take-home points:

  1. Tertill managed rates of efficacy similar to hand and tractor-mounted cultivation tools for both weed types (60-72%)
  2. Tertill’s weed control decreased by 30-40% when not using string-trimmer
  3. Tertill’s simple and effective design could offer insights in the design of farm-scale robots

Agricultural weeds remain an important production constraint, with labor shortages and a lack of new herbicide options in recent decades making the problem even more acute (Utstumo et al. 2018). Robotic weeding machines are a possible solution to these increasingly intractable weed problems. While several intelligent weeding systems, such as those listed here, are commercially available, the cost associated with technologically complex systems can be prohibitive for smaller farms (Grimstad et al. 2015; Peruzzi et al. 2017). Franklin Robotics’ Tertill™ (Figure 1) is an inexpensive, autonomous weeding robot designed for home gardeners that relies on a minimalistic design to be cost effective.

Our aim was to investigate the performance of the Tertill™ in a controlled environment
using broadleaf and grass surrogate weeds. The objectives of this study were to investigate the ability of the Tertill™ to control broadleaf and grass weeds, with and without its sting-trimmer-like weeding implement, and to evaluate grass weed control over time.

We constructed an experimental arena in the University of Maine greenhouse and filled it with a 7 cm layer of vermiculite beneath a 10 cm layer of field soil. Surrogate weeds, pearl millet and condiment mustard, were sown by hand at a rate of 2,800 seeds m^-2(Brown and Gallandt 2018; Olsen et al. 2005). The weed control efficacy of the Tertill™ was assayed using both surrogate weeds and with and without the robot’s string-trimmer-like weeding implement.

Tertill™ demonstrated high weed control efficacy, supporting its utility as a tool for home gardeners (Figure 2). Weeds were best controlled by the combined effect of soil disturbance caused by the action of the robot’s wheels, and the actuation of the string-trimmer. Despite the regrowth potential of an annual grass due to their meristem location, Tertill™ maintained low densities of millet in an experimental arena (Figure 3). The simple and effective design of the Tertill™ may offer insights to inform future development of farm-scale weeding robots. Weed density, emergence periodicity, robot working rate and weeding mechanisms are important design criteria regardless of the technology employed for plant detection.


Brown B, Gallandt E (2018). Evidence of synergy with ‘stacked’ intrarow cultivation tools. Weed Res. 58: 1-8.

Grimstad L, Pham CD, Phan HT, From PJ (2015). On the design of a low-cost, light weight, and highly versatile agriculture robot. Pages 1-6 in 2015 IEEE International Workshop on Advanced Robotics and its Social Impacts (ARSO). Lyon, France.

Melander B, Lattanzi B, Pannacci E. (2015). Intelligent versus non-intelligent mechanical intrarow weed control in transplanted onion and cabbage. Crop Prot. 72: 1-8.

Peruzzi A, Martelloni L, Frasconi C, Fontanelli M, Pirchio M, Raffaelli M. (2017). Machines for non-chemical intra-row weed control in narrow and wide-row crops: a review. J Agric Eng 48: 57-70.

Utstumo T, Urdal F, Brevik A, Dørum J, Netland J, Overskeid Ø, Tommy J. (2018). Robotic In-row weed control in vegetables. Comput Electron Agric. 154: 36-45.


Figure 1.

Figure 2.

Figure 3.

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