There is so much to do in the garden in spring, especially for gardeners with a lawn to tend to. Mowing, aerating, sowing grass seed and raking out weeds, thatch and moss are all timely tasks, as is top dressing. This refers to applying a mixture of different materials over the lawn’s surface, a gardening technique with many benefits.
According to the green-fingered experts at Fantastic Gardeners, top dressing is most widely known for “producing stunning-looking lawns.” Top dressing is not to be confused with lawn fertiliser, though they can be used together for lawn care. As for when to do it, lawns are best top-dressed during periods of grass growth, so in the UK, that’s anytime between April and October.
Fertiliser provides nutrients to the grass, while top dressing improves the soil structure and can help level the lawn surface. However, some top soil mixtures have added nutrients that can “improve your lawn’s fertility,” according to gardening experts.
Topdressing usually consists of a mixture of soil, sand, loam, and peat, which resembles the soil’s composition.
Fantastic Gardeners noted: “Since topdressing will eventually become part of the root zone, it’s important that it blends well with the already established soil.”
They explained that essentially, topsoil balances out what your existing lawn soil is lacking and “improves resilience” of your grass as a result.
How to topdress a lawn
Sandy soils are free-draining and prone to drought during the hotter seasons. Choose a top dressing mixture of four parts loam, three parts peat, and one part sand.
Clay lawns hold onto water and need a top dressing that improves drainage. Choose a mixture consisting of two parts loam, one part peat and four parts sand.
According to gardening experts, loam-based soil usually falls into the perfect middle. A mixture containing three parts loam, one part peat, and three parts sand can be used.
Do a quick soil test in your garden to ensure you get this spot on. Just pick up a handful of soil and squeeze it together. Gritty, dry soil that doesn’t stick is sand-based, loam is more velvety, and clay soil will initially feel sticky but smooth once rubbed.
Gardener’s World suggests scarifying and aerating your lawn first, then top dressing. Anyone with bare patches on their lawn can follow up with grass seed.
They warned: “Only topdress when the lawn is dry and the weather has been reasonably dry, and you can be sure of finishing the job before it rains again.”
Mow your lawn on a low setting, then wait for the grass to dry completely.
Use a shovel to spread the lawn dressing evenly across the area. A fan-shaped motion is recommended for spreading rather than concentrating it in one place.
Gardener’s World warned that you should use a rubber rake or the back of a straight-headed metal rake to work the dressing into the grass and any hollows or holes. Focus on working the dressing into the root zone so the grass is visible, not to smother the grass.
Once you have worked the dressing into each part of the lawn, gently brush over the grass with a long-handled garden broom.
Avoid mowing your lawn for two weeks after dressing it. If there is no rainfall during this time, water the lawn before mowing it to ensure the top dressing settles thoroughly and the mower removes it.
