SeaGreen Puts Seaweed Biochar in Ten Queen Street Flower Planters

Fredericton's parks crews are running an unusual summer trial on Queen Street: ten downtown flower planters amended with seaweed biochar from SeaGreen Solutions NB. The City announced the pilot on July 14 as part of Planet Hatch's MERGE program — a structured track that pairs early-stage companies with real municipal problems and up to $25,000 in project funding.

The city pays 25 per cent of project costs (up to $6,000); MERGE covers the balance. Startups get a paying first customer, mentoring from a business development officer, and Planet Hatch membership with access to Ignite programming.

"Through these projects, startups gain access to funding, business support, and valuable customer feedback to accelerate market readiness," the City said in its announcement.

From Bay of Fundy wrack to pyrolyzed soil amendment

SeaGreen was founded by Marie Dankworth, a doctoral student in biology at UNB whose research centres on Bay of Fundy seaweed, and her partner Joel Thompson. The process: harvest beach wrack or farmed Atlantic kelp, then subject it to pyrolysis — heating in a low-oxygen environment — to produce biochar.

Unlike wood-based biochars common in agriculture, seaweed biochar retains the ocean minerals the kelp absorbed while growing: magnesium, potassium, and calcium. The porous structure of the resulting material physically locks in moisture and releases it gradually. Dankworth says pots with the amendment hold about 30 per cent more moisture than untreated soil, reducing how often city staff need to water.

"The biochar holds moisture well, meaning less watering for flowerpots and green spaces," Dankworth said.

"Fredericton is Atlantic Canada's knowledge capital, and the city is pleased to be piloting innovative technology developed locally by Seagreen Solutions, a company with roots at UNB," said Mike LaCroix, foreman in the parks and trees division at the City of Fredericton. "As the City continues to advance projects that support a resilient, sustainable community, we remain open to exploring new technology that will help our city thrive well into the future."

Early wins, garden-centre ambitions

SeaGreen is currently sourcing seaweed from beach wrack — material that would otherwise decompose and release its carbon back to the atmosphere. Kelp farming in the Bay of Fundy is a longer-term ambition. The startup has also been running trials with organic growers and home gardeners this season, and is pursuing business-to-business garden centre sales in Fredericton.

Early validations already stack up: Best Video at the 2026 Boost Ideation Camp, first prize in the growth category at UNB's RBC Pitch Competition in March, and a spot in the 2026 Ocean Idea Challenge, which offers up to $8,000 in funding to 23 selected startups.

Boost Ideation — run each year by the City, UNB, NBCC, and Ignite at Planet Hatch — is where SeaGreen first built a municipal prototype. MERGE is designed to take the strongest camp ideas into a funded, real-world proving ground. A sibling MERGE pilot this summer is Cloudboids' Compliance AI for building permits.

Sources

• City of Fredericton LinkedIn, July 14, 2026 — pilot announcement
• Ignite / Planet Hatch news release, July 14, 2026 — programme context
• UNB Newsroom, June 11, 2026 — SeaGreen founder profile with pilot and competition details
• BiocharToday, June 30, 2026 — technical biochar pilot detail
• Planet Hatch MERGE program page — funding structure ($25K / 25% municipality match)
• City of Fredericton 2026 Boost Ideation Camp results, January 21, 2026 — Best Video award