What does fertiliser really cost per feed? The maths brands hide
The fair way to compare fertiliser prices is cost per feed: the price of one full 9 L watering can of mixed feed. On that measure a quality concentrate is one of the cheapest things in the garden. A 5 L bottle of our concentrate at 2.5 mL per litre makes 2,000 L of feed, which is 222 watering cans at about 45c each. Typical garden-centre concentrates work out at 2 dollars or more per feed. The sticker price of the bottle tells you almost nothing.
Fertiliser is sold by the bottle but used by the watering can, and that gap is where most gardeners lose money. Here is the maths, out in the open.
The only formula you need
Cost per feed = bottle price divided by the number of watering cans it makes. To get the number of cans: litres in the bottle, divided by the dose per litre of water, times 1,000, divided by 9 (a standard full can). Two numbers on any label give you everything: bottle size and dose rate.
The maths on our range
| Bottle | Makes | Feeds (9 L cans) | Cost per feed |
|---|---|---|---|
| 1 L ($32) | 400 L | 44 | about 73c |
| 5 L ($99) | 2,000 L | 222 | about 45c |
| 20 L ($315) | 8,000 L | 888 | about 35c |
| 5 L Bundle ($169, both feeds) | 4,000 L | 444 | about 38c |
That is why the bigger bottle is nearly always the right buy for an established garden: the 5 L costs three times the 1 L and makes five times the feed.
Why cheap bottles are expensive
A 2 L ready-to-pour bottle for 10 dollars sounds cheap until you notice it is not a concentrate at all, or doses at 50 mL per litre. Run the formula and many supermarket options land between 1 and 3 dollars per feed. Hose-on bottles are convenient, but you are mostly buying water. Dose rate is the whole game: a 2.5 mL per litre concentrate is 10 to 20 times more concentrated than most of the shelf.
What a season actually costs
A typical home garden on the fortnightly routine uses maybe 2 to 4 cans a week through the season: lawn, veggie bed, pots, roses. Call it 60 to 100 feeds from September to May. On a 45c per feed concentrate that is a 30 to 45 dollar season for the whole garden. On a 2 dollar per feed product, the identical routine costs 120 to 200 dollars. Same watering can, same effort, quadruple the money.
Common questions
Does concentrated mean harsher?
No. Concentration describes the bottle, not the plant's experience. Once diluted to label rate, a concentrate is exactly as gentle as its mixed strength, and dilute liquid feeding is the low-burn way to feed. See liquid vs granular for the wider comparison.
How long does a bottle last?
On the season above, a 5 L bottle of one feed covers roughly two full seasons of that feed's share of the routine. Sealed concentrate stores fine in the shed out of sunlight.
Is the bundle cheaper than buying separately?
Yes: the 5 L bundle saves 29 dollars against the two bottles bought alone, and it clears the 149 dollar free-shipping mark on its own.
Put it into practice
Medigrow builds growth, Medibud brings the bloom. The bundle covers the whole season from 38c a feed, backed by the 30-Day Growers Guarantee.
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