Ammonium sulfate on 5 m² — 238.1 g for 10 g/m² of N
To put 10 g/m² of N on 5 m² with Ammonium sulfate, spread 238.1 g — that is 47.62 g per m². At 21% content it is simply the 50 g of nutrient you need divided by that figure.
Fertilizer to spread
Urea is only 46% nitrogen, so putting 10 g of N down means spreading 10 ÷ 0.46 = 21.74 g of urea. Multiply instead and you get 4.6 g, a number that looks plausible enough to pass unnoticed. Whenever the content is below 100%, the fertilizer weight is always larger than the nutrient weight — that is the fastest check that you have the division the right way round.
- N 5 g/m² · 23.81 g/m²119 g
- N 10 g/m² · 47.62 g/m²238.1 g
- N 15 g/m² · 71.43 g/m²357.1 g
- N 20 g/m² · 95.24 g/m²476.2 g
- Fertilizer
- Ammonium sulfate (21-0-0)
- Area
- 5 m²
- Nutrient matched
- N
- Content
- 21%
- Nutrient needed
- 50 g
- Per m²
- 47.62 g
Nearby cells
Same fertilizer, other areas
Same area, other fertilizers
Worth knowing
- Fertilizer to spread = nutrient needed ÷ (content ÷ 100). It is a division, never a multiplication.
- Nutrient needed = area × target rate, so twice the area means twice the fertilizer.
- A fertilizer with half the content takes twice as much for the same nutrient — inverse proportion.
- With a compound, matching one nutrient drags the other two in at their content ratio.
Common questions
Q. How much Ammonium sulfate goes on 5 m²?
At 10 g/m² of N, 238.1 g — that is 47.62 g per m². It is the 50 g of nutrient needed divided by the 21% content.
Q. If I double the target, do I double the fertilizer?
Yes. Target and fertilizer weight are directly proportional — 5 g/m² takes 119 g and 20 g/m² takes 476.2 g. Area behaves the same way: twice the area, twice the fertilizer.
Q. What else goes in along with it?
Ammonium sulfate carries only N, so nothing else comes along. The other nutrients have to be supplied by separate fertilizers.