Calculating lawn area and seeding rate correctly
Too little seed leads to a patchy lawn, too much causes excessive competition between seedlings
The area calculation follows the well-known geometry formulas: rectangle = a × b, circle = π × r², triangle = (base × height) / 2. Irregularly shaped gardens can usually be broken down into several simple partial areas, which are calculated separately and then added together.
Seeding rate per RSM standard: For a new lawn, the regulated seed mixtures (RSM) standard typically calls for 25–30 g/m², while high-quality branded seed can sometimes get by with as little as 20–25 g/m². Fine ornamental lawn mixes tend to need less, at 15–20 g/m², while robust sports and play lawn mixes with a ryegrass share tend towards 25–30 g/m².
Overseeding saves seed: Since grasses are already growing in an existing lawn, roughly half the new-lawn quantity is enough for overseeding – for most lawn types that means 8–17 g/m², depending on the starting condition of the lawn.