Azolla — Living Biofertilizer
Fairy moss isn’t just a pond plant. It’s a nitrogen-fixing aquatic fern with a thousand-year history in sustainable agriculture — and it grows for free in our pond in Milwaukie, Oregon.
The Science
What Makes Azolla Remarkable
One of the fastest-growing plants on earth, with a built-in nitrogen factory that’s been feeding crops for over a thousand years.
Nature’s Nitrogen Factory
Azolla hosts a symbiotic cyanobacterium (Anabaena azollae) inside its leaf cavities that converts atmospheric nitrogen directly into plant-available fertilizer. This makes Azolla one of the only plants that can fertilize itself — and the soil around it — without any synthetic inputs.
Research published in Sustainability (MDPI, 2023) found that Azolla biofertilizer is an effective replacement for urea fertilizer in vegetable crops. Studies show Azolla-Anabaena complexes can fix up to 1,100 kg of nitrogen per hectare per year — nearly three times the rate of leguminous cover crops.
Asian rice farmers have used Azolla as a green manure for over a thousand years, growing it on flooded paddies and incorporating it into soil before planting. Modern permaculture and regenerative agriculture communities are rediscovering it as a living fertilizer system.
Azolla vs. Other Nitrogen Sources
| Source | N₂ Fixed / ha / year | Synthetic Inputs? |
|---|---|---|
| Azolla-Anabaena | ~1,100 kg | None |
| Legume cover crops | ~400 kg | None |
| Urea (synthetic) | Variable | Yes (fossil fuel) |
Source: Azolla Foundation; MDPI Sustainability 2023.
Two Markets, One Plant
For Ponds & For Gardens
The same Azolla that covers your pond also feeds your soil. We sell it fresh for both uses.
Natural Pond Cover
Forms a dense, velvety mat that blocks light algae needs to grow, suppresses mosquito breeding by covering the water surface, and adds a rich green-to-red texture that changes color with the seasons. Provides shelter for fish and pond life.
Compost Activator
High nitrogen content accelerates decomposition in compost piles. Mix fresh or dried Azolla into your compost bin to boost microbial activity and enrich the finished product with nitrogen, phosphorus, potassium, and micronutrients.
Green Manure
Till fresh Azolla directly into garden beds before planting, just like a cover crop. As it decomposes, it releases nitrogen and organic matter into the soil. Especially effective in raised beds, no-till systems, and container growing.
Living Mulch & Side-Dress
Apply fresh Azolla around the base of vegetables, fruit trees, and perennials. It suppresses weeds, retains moisture, and slowly releases nitrogen as it breaks down. Works particularly well around heavy feeders like tomatoes, squash, and corn.
Potting Mix Additive
Blend dried Azolla into custom potting mixes for slow-release nitrogen. Reduces or replaces synthetic fertilizer in container growing. Useful for nurseries, seed starting, and houseplant soil mixes.
Worm Bin Food
Vermicomposters use Azolla as a high-nitrogen input that worms process readily. Produces nutrient-dense castings. A renewable, pond-grown alternative to purchased worm food.
Self-Renewing Supply
Your Pond Is a Biofertilizer Factory
Buy Azolla once. Harvest fertilizer all season. It doubles every 2–3 days, so a small starter portion produces a continuous, self-renewing supply.
How It Works
Start with a small portion of living Azolla in any body of still water — a backyard pond, a stock tank, even a kiddie pool. Under decent conditions (sunlight, still water, moderate temperatures), it doubles its biomass every 2–3 days.
Harvest the excess weekly by scooping it off the surface with a net or colander. Apply it fresh to your garden beds, toss it in the compost pile, or dry it on a screen for later use. The remaining Azolla in the water replenishes itself within days.
One initial purchase creates a season-long supply of nitrogen-rich biofertilizer at essentially zero ongoing cost. In the Pacific Northwest, Azolla grows actively from late spring through early fall.
Growing Requirements
Who This Is For
From Backyard Ponds to Market Gardens
Azolla works at every scale. Here’s how different growers are using it.
Pond Owners
If you have a backyard pond, Azolla gives you natural mosquito suppression, algae competition, and a living green carpet that changes color with the seasons — all while quietly producing biofertilizer you can harvest for your garden beds.
Organic & Permaculture Growers
Azolla is a nitrogen source that doesn’t come from a bag or a factory. It integrates naturally into permaculture systems, no-dig beds, and organic growing operations where synthetic inputs aren’t an option. Grow it in a stock tank next to your garden and harvest weekly.
Market Gardeners & Small Farms
At farm scale, Azolla can supplement or replace purchased nitrogen fertilizer for vegetable production. Grow it in irrigation ponds or dedicated tanks and apply as green manure or side-dress. The economics improve with scale — the input cost is essentially the water surface area.
Ideal For
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Get in Touch
Questions & Orders
Interested in Azolla for your pond, garden, or farm? Email us for current availability, quantity guidance, and bulk pricing.
sales@seaspores.orgMilwaukie, Oregon — Local delivery in the Pacific Northwest plus nationwide shipping