If your lawn doesn’t seem to be growing as well as it should, even though it’s being fed regularly, it may be because of either thick thatch or compacted soil (or both). In both cases, the grass is suffering because air, water, and nutrients aren’t able to move freely into and through the soil, and are having trouble reaching the roots. You can tell your soil is overly compacted if you can’t easily insert a screwdriver into it. When thatch (bits of grass that have died and gathered just above the soil line) is too thick, your lawn will feel spongy, and it will be difficult to stick your finger through to the soil.
Either way, you need to take action.

After the lawns have been dethatched it is beneficial to lightly feed your lawns with fertilizer to encourage grass growth.