Project Overview
Commodities
- Vegetables: beets, carrots, cucurbits, greens (leafy), greens (lettuces), onions, radishes (culinary)
Practices
- Crop Production: varieties and cultivars, water management
- Education and Training: demonstration, farmer to farmer, mentoring, on-farm/ranch research, participatory research, youth education
- Farm Business Management: labor/employment
- Natural Resources/Environment: soil stabilization
- Pest Management: mulches - general
- Sustainable Communities: local and regional food systems, public participation, quality of life, urban agriculture
Summary:
Problem Addressed:
Hand weeding vegetables is time consuming and back-breaking, particularly in narrowly spaced crops like leafy greens, carrots, and green onions. Many urban farmers and gardeners have full-time jobs off the farm and tend their crops in the evenings and on weekends, which makes the opportunity cost of hand weeding particularly severe. Common alternatives to hand weeding in these crops include stale seed bedding, flame weeding, and tillage with harrow and tine weeders; however, stale seed bedding displaces valuable time in an already short Minnesota growing season and flame weeding and tillage are time-sensitive, only partially effective, and can cause significant crop damage. For most of our crops, mulching is the most promising option for lasting weed suppression during the growing season, but traditional plastic mulch films and geotextile fabrics are not feasible for narrowly spaced crops because the number of planting holes required compromises the integrity and function of the barrier. In addition, plastic-based films and fabrics can contaminate soil and must be removed and landfilled at the end of their useful life. We need a viable biobased, mulching strategy to eliminate hand weeding in narrowly spaced crops on our farms.
Research Approach:
We used a mother-baby experimental design whereby there was one controlled, replicated “mother” trial at Frogtown Farm and at least 3 non-replicated “baby” trials at each farm. Baby trials were valuable for providing additional replication of treatments in the mother trial (additional validation) and for demonstrating the technology under real-life conditions (thereby improving the potential for farmer adoption). In the mother trials, RootThru was compared to a combination of mechanical and hand weeding across three replicated, randomized experimental plots.
Research Conclusions:
RootThru successfully suppressed weeds in narrowly spaced vegetable crops, as evidenced by growers' enthusiasm and anecdotal success, reducing the labor-intensive burden of hand weeding. While RootThru showed strong potential, cost-effectiveness compared to traditional methods (hand weeding, straw mulch) remains to be quantified. Future trials will need to assess economic viability for widespread adoption. One of the most effective and unexpected applications was the use of RootThru in farm walkways, where it nearly eliminated the need for weeding and significantly reduced non-productive labor required to maintain field access.
Farmer Adoption:
The mother-baby trial approach was valuable for both controlled testing and real-world demonstrations, enhancing credibility and farmer buy-in.
Project objectives:
Toward the goal of eliminating hand weeding in narrowly spaced, high density vegetable crops, we will test the RootThru Weed Barrier in comparison to our current weed management practices. RootThru is a composite geotextile fabric made from two sustainable, 100% plant-based materials – paper and corn. RootThru is unique from other weed barriers because we can plant our seeds directly on the barrier and the seedlings grow and root through it; and yet, weed growth is effectively suppressed below the barrier. Unlike plastic-based weed barriers, RootThru is biobased and can be taken to a composting facility after field removal instead of the landfill.
RootThru is installed by following these four steps: 1) prepare the soil by removing weeds and creating furrows for seeds; 2) unroll the weed barrier onto the soil, form fabric into furrows, and secure the edges with soil or landscape staples; 3) plant seeds into furrows directly on the fabric or into a layer of weed-free compost or soil mix; 4) cover seeds with additional compost or soil mix and irrigate daily until seeds have germinated and rooted through the fabric. Once established, RootThru eliminates the need for hand weeding and frees time and energy to create value elsewhere on the farm.
We received free sample rolls of RootThru in July 2023 to test at Frogtown Farm and Kilimo Minnesota Farm in carrot, radish, turnip, sweet corn, jute, and collard greens. Results were promising and individual growers were enthusiastic about the product. Nura Ahmed, a long-time grower at Frogtown Farm said, “I couldn’t believe it, there are no weeds [in my jute crop] …that is really amazing!” Given the initial anecdotal success of RootThru, we would like to expand its use on our farms and quantify the potential benefits for our farms and share those results with other growers.
In 2024, we will establish field research and demonstration trials at Frogtown Farm and Kilimo Minnesota - Lino Lakes Farm to compare the RootThru Weed Barrier with existing farmer weed management practices (including straw mulching, hand weeding, and tine weeding). We will use a mother-baby experimental design whereby there is one controlled, replicated “mother” trial at Frogtown Farm and at least 3 non-replicated “baby” trials at each farm. Baby trials will be valuable for providing additional replication of treatments in the mother trial (additional validation) and for demonstrating the technology under real-life conditions (thereby improving the potential for farmer adoption). In the mother trials, RootThru will be compared to a combination of mechanical and hand weeding across three replicated, randomized experimental plots.
At the end of the experiment, RootThru will be removed from the field and delivered to a commercial composter, Specialized Environmental Technologies (SET) in Rosemount, MN. SET will also provide the compost necessary for the trials, demonstrating the full circularity and sustainability of the RootThru system (whereby compost produced from RootThru in one season can be used to grow crops in RootThru in subsequent seasons).
Data collection plans from these field trials are summarized in the “Measuring Results” section below.