In agriculture, both field production and greenhouse cultivation play essential roles. Field systems harness natural conditions at enormous scale and lower infrastructure cost.Greenhouses, on the other hand, reduce environmental variability and allow producers to manage temperature, nutrients, pests, and seasonality.

Neither approach is inherently “better.” They simply solve different problems and produce different products.

The same dynamics exist in seaweed production with ocean and land-based approaches to cultivation. Ocean farming captures natural productivity where conditions are favorable and society/logistics allow large-scale deployment.

Land-based cultivation introduces a higher degree of environmental control and can provide something the ocean cannot always guarantee, predictability in both tonnage produced and biomass composition.

As global demand for seaweed compounds for food, feed, nutraceutical and self-care ingredients grows, the industry will continue to rely on a combination of ocean and land-based approaches, each optimized for local conditions, biology, and risk tolerance.

The future of seaweed farming is unlikely to be one system replacing another. It will be about choosing the right production environment for the biological and commercial objective.

If you would like to chat more about the possibilities with land-based seaweed cultivation, please feel free to reach out www.totallyseaweed.com

Specific growth rate (% per day) is one of the most reported metrics in academic seaweed papers. But in commercial cultivation, it’s often one of the least useful.

Specific growth rate (% per day) varies with the amount of biomass present in the system. It can be thought of as how rapidly individuals are accumulating biomass.

But in commercial systems, what is important to measure is system productivity (g dry wt / m² / day), not specific growth rate.

A land-based seaweed tank can be thought of as a solar energy collector, converting this energy into biomass to be harvested, therefore density is usually measured against m2 of available tank area. When biomass is stocked within the optimal stocking density range (Kg / m2), and water movement, nutrients, & pH are all non-limiting, system productivity typically:

✅ Remains constant and predictable, varying only with available light.
✅ Reflects true system output, and can be compared with other systems and species when dry weight productivity is measured.
✅ Directly connects to revenue potential, and can be used to track tank performance against expectations so that corrective actions can be taken.

Optimal density production is very important here since rapidly growing (i.e., high specific growth rate) seaweeds have lower solids content than slower growing seaweeds. Therefore, when land-based seaweed tanks are stocked within the optimal density range, specific growth rates (% per day) are lower, and solids content and system productivity (dry g / m² / day) are maximized. More solids equate to higher yields when drying and better-quality biomass (e.g. protein, pigment, other bioactives), enhancing your operation’s bottom line.

Commercial cultivation is not about how fast each individual grows. It’s about how much biomass your system delivers per unit area, per unit time, at harvest.

These subtleties are not obvious to new producers starting up land-based operations, so feel free to reach out. I am always happy to talk seaweed! www.totallyseaweed.com

A good, clean, vegetative and productive cultivar is the most valuable asset any land-based seaweed farm has. Overcoming the reliance on seasonal cycles of reproduction leads to the simplification and streamlining of commercial production. This can be the difference between success and failure. It also doesn’t require a rocket scientist or an expensive laboratory to develop a cultivar in-house (you do need to be meticulous and persistent though)! These are some characteristics of what I consider a “good” cultivar:

✅Highly productive on a dry weight basis

✅Clean of all colonizing organisms and able to be maintained in this state indefinitely

✅Resistant to epiphyte/endophyte colonisation during outdoor cultivation

✅Remains vegetative during an entire annual cycle

✅Wide range of temperature tolerance

✅Morphology acceptable: eases material handling, processing, value addition

✅Generally robust and not sensitive to handling or short periods of stress when systems fail (they always do eventually).

✅Tastes great in final form and/or is high in some commercially relevant compound of interest.

If you are struggling with productivity, epiphyte overgrowth, or periodic reproductive events that shut productivity down, feel free to reach out. Many of these issues can be overcome by developing the right cultivar for your operation. www.totallyseaweed.com 

Scaling to commercial success with seaweed cultivation is never successful when powered by optimism alone. Success during short-term, pre-commercial trials can make it seem like the path to scale is just to do MORE of the same. But once you have gone through the scaling process a few times with a few commercially interesting seaweed species like I have, you begin to see what questions are important to answer early on. Some of the early questions that I always ask include:

✅Is it better to be a producer of commodity products that are sold to a central buyer, or should value be added, or retail products be developed in-house before sale?

✅How much total annual tonnage is needed to be profitable, where is the immediate market, who is competing in this space, and where will market growth come from?

✅How much energy is required, how can energy be utilized most effectively during production and preservation, and is the system designed for success from the start?

✅Will productivity be predictable season after season with the current propagation strategy and is there complete control over starting biomass?

✅Will the cultivar maintain productivity indefinitely, and how can predictable and consistent productivity be designed?

✅How much risk do disease outbreaks and epiphyte contamination represent, and how can these risk be minimized?

These are difficult questions to answer when scaling up production for the first time, and there is no handbook or template to follow with on-land seaweed cultivation. I started Totally Seaweed Consulting (www.totallyseaweed.com) to help companies navigate these challenges as they scale production or trouble shoot existing operations. Feel free to reach out if you are struggling with any of these questions, I am always happy to talk seaweed! 

The 20L (5 gal) bucket is the most useful piece of equipment in all of Phycology. OK, maybe a little overstated, but…over my career, I have used these buckets with a variety of seaweed cultivars to determine:

✅Nutrient requirements for optimal productivity

✅Prevention of epiphytes

✅Effects of seaweed extract usage (bio-stimulants) on stress resistance

✅pH set point effects on productivity and carbon usage

✅Upper limits for protein, pigment and nutrient accumulation in tissue

✅Temperature optima and upper limits for health

✅Induction of stress for bioactive compound production

✅Productivity comparisons among cultivars of interest

✅Artificial light spectra effects on productivity

✅Simulations of winter and summer conditions to predict productivity

What you can learn from a 20L bucket, whether from Ace Hardware (Hawaii) or Canadian Tire (Canada) is extremely valuable in predicting effects during full scale production (up to 600m2). These small-scale trials, when set up with simple temperature, light and pH control can lead to rapid progress in optimizing production. R&D equipment doesn't have to be expensive!

If you would like to learn more about my approach to cost-effective R&D, please reach out and/or visit www.totallyseaweed.com . I am always happy to talk seaweed.  

Scaling on-land seaweed cultivation beyond pilot scale can be daunting. At early stages, it often appears that commercial success is simply a matter of increasing tank size or number to match site targets.

In practice, this assumption is where many projects encounter trouble.

As systems scale, a new set of challenges emerges that directly affect productivity, operating cost, and profitability:

1. Underestimating the amount of energy, or the best way to use energy to keep the biomass in large scale cultures mixed and evenly distributed within the vessel.

2. Nutrient loading that worked well at small scale but now is inadequate to maintain productivity or bioactivity at harvest without epiphyte enhancement at scale.

3. Large-scale vessel designs that lead to higher-than-expected labour costs during production, maintenance and harvesting.

4. Morphological/biochemical changes in the cultivar of interest that occur late in the grow-out cycle that were not apparent at smaller scales.

5. Difficulties in maintaining health of the cultivar during seasonal stresses that could be managed easily when cultures were small (eg, use of shading, heat exchange or water flow to maintain temperature at scale).

Because on-land seaweed cultivation is a relatively new technology there is no universal playbook for success. And even if there was some magical handbook available, these problems are usually site or species specific.

The best method to overcome these challenges is to work with someone who has experienced each of these challenges and overcome them.

Totally Seaweed Consulting (www.totallyseaweed.com) was formed to help de-risk the jump to full scale production, and if you are interested in how I can help you take that leap toward profitable scale-up please reach out! I am always happy to talk seaweed. 

On-land seaweed cultivation had its beginnings in Canada when, in 1968, AC Neish, JS Craigie, and JL McLachlan began efforts to keep up with the global demand for carrageenan by investigating tank cultivation of Chondrus crispus at NRCC Nova Scotia (fun fact: JL McLachlan is the father of Canadian singer/songwriter Sarah McLachlan). The first 4x8ft. plywood and plastic lined tank was constructed in 1971, which used a washing machine motor to turn a wooden paddlewheel for agitation.

This tank style was commercialized in 1975 by Iain Neish (with Atlantic Mariculture) on Grand Manan Island for the improvement of Palmaria palmata quality. These basic cultivation techniques were fully commercialized by Marine Colloids (FMC Corporation) who scaled up in Nova Scotia initially using paddlewheel raceways and later moved to large, aerated ponds for Chondrus crispus production for carrageenan extraction. When Eucheuma and Kappaphycus cultivation in the Philippines and Indonesia began to supply the carrageenan industry at lower prices and higher volume than Canadian cultivation efforts (1980’s), the Canadians (Acadian SeaPlants Limited) pivoted to a unique, Japanese-style food product from cultivated Chondrus crispus, and later industrialized the production of Palmaria palmata on-land.

In North America, these techniques spread to the West Coast where Marine BioProducts in BC were the first to cultivate Gelidium vagum at scale (for agarose extraction), expanding in Kona Hawaii in the late 1990’s. Devalerea (Palmaria) mollis was the next to be commercialized on-land by a group at Oregon State University (Chris Langdon), and fully industrialized as feed in Kona Hawaii by Big Island Abalone Corporation (early 2000’s). This same D. mollis cultivar is currently in production at Oregon Seaweed for high quality human food production. Royal Hawaiian Sea Farms in Kona and Monterey Bay Seaweeds in California are also notable for cultivating a variety of species on-land. The newest North American operation to cultivate on-land is Symbrosia in Kona, commercializing Asparagopsis as a methane reducing feed.

From the start, efforts to improve quality, or to supply industry with unique products has been the driving force behind on-land seaweed cultivation. We are seeing these same forces at work today with new systems and species under development world-wide. Recent innovations in bioremediation, water treatment and IMTA are relatively new and are now also driving innovation and scale forward. And just think, it all started in 1971, in a plywood bathtub with an old washing machine motor in Nova Scotia Canada. 

During on-land seaweed cultivation, optimized nutrient loading is a fundamental design parameter that cannot be overlooked. Off-the-shelf and well-known lab formulations like f/2 or PES are not optimized for commercial scale production. In practice, these recipes often:

- Provide unbalanced nutrient ratios for your cultivar
- Oversupply costly elements while undersupplying others
- Unintentionally feed colonizing/competing organisms or negatively impact crop health

When nutrient demands are not balanced by supply, opportunists thrive and productivity suffers. Optimized nutrient loading means feeding your crop exactly what it needs to thrive and nothing more. For a generalized example, with many red seaweeds you will want to keep a close eye on the amount of phosphorus you are delivering, since opportunistic green seaweeds will benefit from high phosphorus loading. Non-optimized nutrient loading can lead to:

- Increased epiphyte colonization

- Loss of productivity

- Declines in cultivar health and product quality

- Higher labour and cleaning costs

It is only with land-based systems that you can ethically take advantage of nutrient loading, boosting growth or targeted components like protein (more on enhancement of target/bioactive compounds in land-based systems in an upcoming post). With flow-through paused during dosing, nutrients are fully utilized by the target crop (optimizing nutrient costs) and eutrophication of surrounding ecosystems is prevented.

If you're cultivating seaweed on land, nutrient load design should never be just a side concern. It’s a strategic lever that can enhance quality, productivity, and profitability.