cal mag
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
Conversion
Incredible12.5%search→purchase rate — share of searches ending in a sale
Avg price
Great$21.06avg listing price — sweet spot $15–$100
Price range
Great$11.44–$40.83cheapest to priciest tracked listing — scored on the share inside $15–$100
Market size
Good$801K$801K/yr · 305K searches
Growth
Good+43.9%90-day search growth — must beat 0% to launch
Competition
Okay67%top-5 click share — leaders hold, buyers still browse
Brand share
Okay87%top-5 brand share — brands hold most of the demand
Review moat
Bad4,185.5avg incumbent reviews — the moat a new listing must climb
Quality gap
Bad4.7★avg incumbent rating — lower means beatable quality
According to Flapen's Amazon United States niche tracking, cal mag is a $801K/yr Amazon United States market (305K searches/yr). The top 5 brands hold 87% of demand. Demand peaks in May–Jun–Jul. Verdict: Worth a look — 59/100.
Data updated Jul 15, 2026 · scored weekly · How we score niches
cal mag market data
- Units sold / yr
- 30K–40K
- avg 2,000–2,500/product
- Revenue / yr
- $632K–$842K
- units × avg price
- Conversion rate
- 12.5%
- Avg BSR
- #494
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 78%
- Out of stock
- 0.0%
- Avg brand age
- 106 months
- Avg seller age
- 158 days
Competition & brand share
The top 5 products take 67% of clicks — established leaders, but buyers still shop beyond them.Brands
10 falling
Sellers
63
Top-5 brand share
87%
Top 20: 100%
Top-5 click share
67%
Top 20: 100%
Open market
6%
- Bloom City30%
- Botanicare23%
- General Hydroponics16%
- FoxFarm10%
- TPS NUTRIENTS9%
- Athena7%
- Open — no brand owns it (4 brands, 6%)
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — +43.9% search growth over the last 90 days.Peak months: May, Jun, Jul · busiest ÷ quietest = 2.2×
Top cal mag search terms
- cal mag99K/yr
- cal mag for plants55K/yr
- calmag48K/yr
- calmag for plants24K/yr
- cal-mag11K/yr
- calmag for cannabis12K/yr
- cal-mag for plants8K/yr
- calmag+7K/yr
- cal mag for cannabis18K/yr
- cal mag fertilizer4K/yr
Top cal mag 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 18 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Bloom City Professional Grade Ultra Pure Cal-Mag Growing Fertilizer Quart (32 oz)
Bloom City$17.404.7★6,860 rev
Botanicare Cal-Mag Plus A Calcium Magnesium And Iron Plant Supplement Corrects Common Plant Deficiencies Add To Water Or Use As A Spray 2-0-0 NPK Quart
Botanicare$18.284.7★19,666 rev
General Hydroponics CALiMAGic Quart
General Hydroponics$18.054.8★9,493 rev
Bloom City Professional Grade Ultra Pure Cal-Mag Growing Fertilizer 1/2 Pint (8 oz)
Bloom City$11.474.7★6,860 rev
FoxFarm Bush Doctor Cal Mag for Plants -OMRI Listed for Organic Gardening - 1-0-0 3% Calcium 0.9% Magnesium - 1-Pint
FoxFarm$17.964.7★2,926 rev
Newest
by launch date
Athena Blended CaMg | Cal Mag for Plants | Calcium Magnesium Fertilizer | Calmag for Hydroponics Coco & Soil | NPK 2-0-0 | 32 Ounce
Athena$16.27165 rev
16oz Cal Mag for Plants - Makes 96 Gallons of Calmag for Plants Fertilizer Liquid Cal-Mag for Plants Indoors & Outdoors Ideal Calmag Supplement with 3-0-0 NPK - Corrects Common Plant Deficiencies
HiThrive$12.9644 rev
Cal-Mag for Plants Plus Iron and Micros Calcium and Magnesium Prevent Common Deficiencies 2-0-0 CalMag Liquid Plant Fertilizer 8 oz
TPS NUTRIENTS$11.44242 rev
Cal-Mag Complete Calcium Magnesium Supplement with Micronutrients to Correct Deficiencies in Soil & Hydroponics 8 oz
TPS NUTRIENTS$13.04586 rev
Botanicare Cal-Mag Plus Calcium Magnesium and Iron Plant Supplement 2-0-0 1 qt.
Botanicare$19.32279 rev
Trending
90-day click momentum16oz Cal Mag for Plants - Makes 96 Gallons of Calmag for Plants Fertilizer Liquid Cal-Mag for Plants Indoors & Outdoors Ideal Calmag Supplement with 3-0-0 NPK - Corrects Common Plant Deficiencies
HiThrive$12.964.7★
Bloom City Professional Grade Ultra Pure Cal-Mag Growing Fertilizer Gallon (128 oz)
Bloom City$36.674.7★
Athena Blended CaMg | Cal Mag for Plants | Calcium Magnesium Fertilizer | Calmag for Hydroponics Coco & Soil | NPK 2-0-0 | 32 Ounce
Athena$16.274.8★
Bloom City Professional Grade Ultra Pure Cal-Mag Growing Fertilizer 1/2 Pint (8 oz)
Bloom City$11.474.7★
Bloom City Professional Grade Ultra Pure Cal-Mag Growing Fertilizer Quart (32 oz)
Bloom City$17.404.7★
What buyers say about cal mag
What buyers praise and complain about, mined from review topics.What buyers love
“The plants love it”
“Reliable quality and consistent results”
“Easy to use”
“Great value for the money”
“As advertised”
“This stuff is strong, reliable and never runs out”
“A large supply ad it works”
“Within just a short time of using it, I noticed stronger stems, healthier leaves, and a deeper, richer green color overall”
“The liquid format makes it easy to work into a regular watering routine without any complicated measuring or mixing”
“No more dry rot at all”
What buyers complain about
“I cant believe how desperate I was getting with my plants”
“I think the instructions have you adding too much”
“Bottle size feels bulky for smaller plant collections”
“so youre not constantly measuring out large amounts”
“The yellowing has gone away”
Top return reasons
Common questions
- Is cal mag profitable to sell on Amazon United States?
- The niche generates $801K/yr across 18 tracked products. 1 of 1 products launched in the last 360 days are still selling. 90-day search growth is +43.9%. Flapen's verdict: Worth a look (59/100).
- How competitive is the cal mag niche?
- 10 brands and 63 sellers compete. The top 5 products take 67% of clicks and top 5 brands hold 87% of demand.
- What do buyers complain about in cal mag?
- Top complaints mined from reviews: Plant Growth, Instructions/User Manual/Troubleshooting, Size-Overall. The return rate is 0.4%.
- When does demand for cal mag peak?
- Demand peaks in May–Jun–Jul; the busiest month runs 2.2× the quietest.
- What does it cost to enter the cal mag niche?
- Listings span $11.44–$40.83; the average listing price is $21.06 (sweet spot $15–$100). The average incumbent carries 4,186 reviews — the moat a new listing must climb.