Fertilizer calculator
Enter your bed size, pick what you're feeding and which fertilizer you have. You'll get the pounds of product to apply and the nutrients it delivers.
How this is calculated
Fertilizer rates are set by actual nitrogen, not product weight. Target nitrogen (lb) = area ÷ 1,000 × the rate for that crop (0.5 lb/1,000 sq ft for light feeders, 1.0 for most vegetables and new lawns, 1.5 for heavy feeders like corn and brassicas).
Product needed (lb) = target nitrogen ÷ (N% ÷ 100). A 10-10-10 fertilizer is 10% nitrogen, so 0.4 lb of actual N needs 4 lb of product. Phosphate and potash delivered are the P and K percentages of that product weight. “Cups” assumes about half a pound of dry granular fertilizer per cup — always check your bag.
Split the total into two or three feedings over the season rather than applying it all at once, and water it in.