Autumn lawn fertiliser

It depends on the recommended amount of nitrogen to be applied to your soil. If you've had a soil analysis done, that will give you the amount that should be applied. If you haven't, in the US, the most generic rule of thumb is 1 lb of Nitrogen per 1000 square feet. For an area of your size (13 meters square/approximately 140 square feet), that works out to just over 2 ounces or roughly 57 grams of actual nitrogen to be applied to the lawn. Now you have to do the math. A

3-10-5 analysis means the contents of the bag is 3% nitrogen. Multiply that by the weight of the bag to get the actual amount of nitrogen by weight in the bag. As a simple example, we'll call it a 10 kg bag. That bag has 300 grams of actual nitrogen in it. You need to apply approximately 57 grams. Round it up to 60 grams to make life simpler. So: you'd apply approximately one-fifth of the bag (2 kilograms) of fertilizer to the lawn.

The recommended rate of nitrogen may vary according to your location and type of grass. Consult with a local professional, then select a product, do the math, and apply the required amount. Save the rest to apply next year according to the recommended application schedule. Frankly, for a lawn as small as yours, there'd be no reason why you couldn't select a small package of garden fertilizer and apply that, as long as you calculate the necessary amount to apply based on the percentage of available nitrogen in the product. You do not want to over-apply nitrogen.