seaweed fertilizer for plants
Worth a lookShows low returns (0.4%), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.
Returns
Incredible0.4%return rate — above 5% kills the launch gate
Avg price
Incredible$24.38avg listing price — sweet spot $15–$100
Conversion
Great11.2%search→purchase rate — share of searches ending in a sale
Growth
Great+86.4%90-day search growth — must beat 0% to launch
Price range
Great$11.84–$40.30cheapest to priciest tracked listing — scored on the share inside $15–$100
Market size
Good$676K$676K/yr · 248K searches
Review moat
Okay2,602.44avg incumbent reviews — the moat a new listing must climb
Brand share
Okay86%top-5 brand share — brands hold most of the demand
Competition
Okay69%top-5 click share — leaders hold, buyers still browse
Quality gap
Bad4.6★avg incumbent rating — lower means beatable quality
According to Flapen's Amazon United States niche tracking, seaweed fertilizer for plants is a $676K/yr Amazon United States market (248K searches/yr). The top 5 brands hold 86% of demand. Demand peaks in Apr–May–Jun–Jul. Verdict: Worth a look — 62/100.
Data updated Jul 15, 2026 · scored weekly · How we score niches
seaweed fertilizer for plants market data
- Units sold / yr
- 20K–25K
- avg 1,000–1,250/product
- Revenue / yr
- $488K–$610K
- units × avg price
- Conversion rate
- 11.2%
- Avg BSR
- #475
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 75%
- Out of stock
- 0.4%
- Avg brand age
- 81 months
- Avg seller age
- 149 days
Competition & brand share
The top 5 products take 69% of clicks — established leaders, but buyers still shop beyond them.Brands
11 falling
Sellers
36
Top-5 brand share
86%
Top 20: 100%
Top-5 click share
69%
Top 20: 100%
Open market
10%
- Bloom City44%
- GS Plant Foods16%
- Blue Planet Nutrients14%
- TPS NUTRIENTS7%
- Grow More5%
- Maxicrop4%
- Open — no brand owns it (5 brands, 10%)
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — +86.4% search growth over the last 90 days.Peak months: Apr, May, Jun, Jul · busiest ÷ quietest = 5.1×
Top seaweed fertilizer for plants search terms
- seaweed fertilizer40K/yr
- kelp fertilizer41K/yr
- liquid kelp19K/yr
- liquid seaweed fertilizer for plants19K/yr
- seaweed extract for plants18K/yr
- liquid seaweed15K/yr
- liquid kelp fertilizer13K/yr
- sea kelp fertilizer8K/yr
- seaweed fertilizer for plants18K/yr
- seaweed extract11K/yr
Top seaweed fertilizer for plants products on Amazon
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 16 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Bloom City Seaweed and Kelp Fertilizer Liquid Seaweed Supplement for Stronger Roots Faster Growth & Improved Stress Tolerance 32 oz
Bloom City$19.204.6★5,473 rev
Bloom City Seaweed and Kelp Fertilizer Liquid Seaweed Supplement for Stronger Roots Faster Growth & Improved Stress Tolerance 8 oz
Bloom City$12.324.6★5,473 rev
Liquid Kelp Seaweed Fertilizer Concentrate - Blue Planet Nutrients Ascophyllum Nodosum Liquid Seaweed Supplement - Makes 470 Gallons - Quart (32 oz)
Blue Planet Nutrients$20.124.7★3,620 rev
GS Plant Foods Liquid Kelp Fertilizer Suitable for Organic Growing OMRI Listed Seaweed Concentrate for Lawns Gardens & Soil - 1 Gallon (Makes Up To 800+ Gallons)
GS Plant Foods$39.374.6★3,436 rev
Seaweed Fertilizer Organic Kelp Plant Food for All Plants Boosts Nutrient Uptake for a Lush Vibrant Garden 8 oz
TPS NUTRIENTS$11.844.5★127 rev
Newest
by launch date
KelpEdge Organic Liquid Kelp Plant Supplement- Seaweed Extract Concentrated Fertilizer Booster OMRI Listed - Boosts Roots Growth & Blooms for Gardens Lawns Veggies Hydro & All Plants
KelpEdge$28.7310 rev
Organic Sea Kelp Fertilizer for Plants Water-Soluble Makes 50 Gallons Kelp Meal Concentrate Plant Food for Indoor Gardens Hydroponics Vegetables Houseplants - Smart Grower - 2oz Bag
Smart Grower$19.56308 rev
Seaweed Fertilizer Organic Kelp Plant Food for All Plants Boosts Nutrient Uptake for a Lush Vibrant Garden 8 oz
TPS NUTRIENTS$11.84127 rev
GS Plant Foods Liquid Kelp Fertilizer Suitable for Organic Growing OMRI Listed Seaweed Concentrate for Flowers Gardens Vegetables & Soil - 1 Quart (Makes Up to 200+ Gallons)
GS Plant Foods$19.7882 rev
Bloom City Seaweed and Kelp Fertilizer Liquid Seaweed Supplement for Stronger Roots Faster Growth & Improved Stress Tolerance 8 oz
Bloom City$12.325,473 rev
Trending
90-day click momentumKelpEdge Organic Liquid Kelp Plant Supplement- Seaweed Extract Concentrated Fertilizer Booster OMRI Listed - Boosts Roots Growth & Blooms for Gardens Lawns Veggies Hydro & All Plants
KelpEdge$28.734.4★
Kelp Bliss (2lbs) - Kelp Meal for Plants - Kelp Meal Organic Fertilizer
plantonix$18.864.7★
Bloom City Seaweed and Kelp Fertilizer Liquid Seaweed Supplement for Stronger Roots Faster Growth & Improved Stress Tolerance 1 Gallon
Bloom City$38.154.6★
GS Plant Foods Liquid Kelp Fertilizer Suitable for Organic Growing OMRI Listed Seaweed Concentrate for Lawns Gardens & Soil - 1 Gallon (Makes Up To 800+ Gallons)
GS Plant Foods$39.374.6★
Bloom City Seaweed and Kelp Fertilizer Liquid Seaweed Supplement for Stronger Roots Faster Growth & Improved Stress Tolerance 8 oz
Bloom City$12.324.6★
What buyers say about seaweed fertilizer for plants
What buyers praise and complain about, mined from review topics.What buyers love
“Its led to so much plant growth, highly effective”
“Great affordable products quality company”
“worth every penny”
“It does not stink at all”
“Incorporated into plant feeding it works as advertised”
“Easy to use”
“follow instruction”
“Effective”
“And green”
“Due to the immense size”
What buyers complain about
“Poor value”
“Smelly”
“Here is my honest breakdown after using it for a full growing season: The Pros: The 7-Day Turnaround: I had a couple of stunted”
“arsenic that could be detrimental to your vegetables plants”
“Half of the product leaked out everywhere before I even got to use it”
“Trash”
“Looked like part of it has been used”
“This was a very small package”
“some of the plants seem hardier than they've ever been”
“The color has dark appearance once diluted in the water”
Top return reasons
Common questions
- Is seaweed fertilizer for plants profitable to sell on Amazon United States?
- The niche generates $676K/yr across 16 tracked products. 1 of 1 products launched in the last 360 days are still selling. 90-day search growth is +86.4%. Flapen's verdict: Worth a look (62/100).
- How competitive is the seaweed fertilizer for plants niche?
- 11 brands and 36 sellers compete. The top 5 products take 69% of clicks and top 5 brands hold 86% of demand.
- What do buyers complain about in seaweed fertilizer for plants?
- Top complaints mined from reviews: Value For Money, Smell, Plant Growth. The return rate is 0.4%.
- When does demand for seaweed fertilizer for plants peak?
- Demand peaks in Apr–May–Jun–Jul; the busiest month runs 5.1× the quietest.
- What does it cost to enter the seaweed fertilizer for plants niche?
- Listings span $11.84–$40.30; the average listing price is $24.38 (sweet spot $15–$100). The average incumbent carries 2,602 reviews — the moat a new listing must climb.