Work out how much sulfur fertiliser or soil amendment you need for an area, from the elemental sulfur rate and the product strength.
Rates and product strengths vary by brand and soil test. Use a soil test to set the rate; this is a planning estimate, not a prescription.
Product needed (lb)
How to use this tool
Enter the area to treat and choose square feet, acres or hectares. The tool converts everything to square feet first.
Use the rate from your soil test or product label, in pounds of elemental sulfur per 1,000 square feet.
Read the sulfur percentage on the bag (for example 90% for elemental sulfur granules) so the tool can convert elemental sulfur into product weight.
The headline result is the total product weight to buy and spread. Add a price per pound to get an estimated cost.
Formula & worked example
A 5,000 sq ft lawn at 1 lb elemental sulfur per 1,000 sq ft needs 5 lb of elemental sulfur, which is 5.56 lb of a 90% sulfur product.
Limitations — read this before you rely on it
This is a planning estimate. Actual sulfur need depends on a soil test, soil pH, texture and the product form, and labelled rates and safety guidance on the bag take precedence. Do not over-apply sulfur to correct pH without a soil test.
Frequently asked questions
Elemental sulfur is the pure sulfur. A bag is rarely 100% sulfur, so you need more product than the elemental amount: divide by the percentage, so 5 lb elemental at 90% strength needs 5.56 lb of product.
Yes, soil bacteria convert elemental sulfur to sulfuric acid over weeks to months, which lowers pH, but the amount needed depends heavily on soil type. Base it on a soil test, not a guess.
One acre is 43,560 square feet. At 1 lb per 1,000 sq ft, an acre needs 43.56 lb of elemental sulfur before the product-strength conversion.
The maths is the same for any sulfur product, but dusting rates for pest or disease control are set by the product label for the crop and pest. Follow the label for those uses.
Only if a soil test shows a need. Sulfur accumulates and over-application can acidify soil and damage plants, so retest rather than repeating a dose automatically.