Fertilizer Calculator

How to use the fertilizer calculator

1. Enter the area to be fertilized, in square meters.
2. Choose the type of fertilizing — spring, fall, or general garden fertilizer.
3. The calculator shows how much fertilizer you need in total, and how many 5 kg bags to buy.

How the fertilizer amount is calculated

The calculator multiplies the area by the recommended fertilizer amount per square meter for the selected type:

Spring fertilizing is typically nitrogen-rich and gives vigorous growth as the lawn wakes up after winter, while fall fertilizing is more potassium-rich and strengthens the grass before winter, for better winter hardiness.

Even spreading matters more than the exact quantity

The right total quantity helps little if it lands unevenly. Spreading by hand almost always produces stripes: areas that received a double dose turn dark green and grow fast, while the strips between them stay paler. With mineral fertiliser, overdosed patches can also scorch the grass, because the salts draw water out of the roots. A spreader that distributes evenly, run in two passes at right angles with half the quantity each way, gives a far more uniform result than one pass at full dose.

Timing matters too. Fertiliser spread just before a hot, dry spell sits undissolved on the surface where it can scorch, while fertiliser watered in — whether by rain or with a hose — is carried down to the roots where it is meant to work.

Frequently asked questions