How To Top Dress a Lawn

The month of April means SPRING and we are all excited to begin gardening outdoors! During April, the first thing most gardeners think about is their lawn. Right now, you probably have a bag or two of high nitrogen lawn fertilizer in your garage just waiting to be spread over the lawn to kick off the growing year in spectacular fashion. Once the snow melts, you might find that your lawn needs a bit more than fertilizer to bring it back to its green glorious self. One amendment boost that you can do in early spring is to top dress your lawn with enriched soil or straight compost. Topdressing a lawn to improve its health has been in use for many centuries. The Scottish began to practice topdressing when they discovered the sport of golf; ( which was in the 15th century by the way) using it to amend the soil under putting greens. If you have a lawn that is older and/or doing poorly, it is advisable to top dress it every second spring (April,May) when the grass begins to actively grow. You can top dress the whole lawn, paying special attention to topping up low spots. Topdressing is especially helpful when amending clay and sandy soils.

What and When

Topdressing is the addition of a thin layer of enriched soil or compost over your existing lawn. This is usually done in late spring after you have dethatched and aerated the turf. 

Why

Topdressing a lawn improves the health of your lawn by adding new soil and nutrients that work their way down through the aeration holes, providing oxygen and water to the grass roots. New roots and grass will fill in the holes, creating a thicker lawn; reducing opportunities for weeds to take hold.

The addition of new soil will help the lawn to retain moisture and keeps the roots cool in summer. It reduces thatch buildup and in some cases improves lawn drainage.

How Do I Top Dress My Lawn?

Fertilize with a high nitrogen spring/summer fertilizer one week before topdressing. This will give the lawn a boost before mowing.

Mow the grass once or twice before dethatching and aerating. Do not mow the lawn too short. Compost the grass clippings as they will block the topdressing soil from filtering down.

Dethatch and aerate the lawn. If the lawn is dry after aeration, water well before topdressing. You can leave the aeration plugs on top of the lawn.

Use your own compost, bagged compost or bags of premixed topdressing soil. Compost supplies a slow release of nutrients and improves soil structure.

You can also create your own mix of 3 parts compost enriched soil, 1 part peat and 1 part horticultural/sharp sand. A wheel barrow makes a great mixing bin and can be easily moved around the yard.

Sharp sand can be purchased at some Saskatoon Landscape Supply retail outlets. Mix well and if needed, screen this mixture which reduces the size of the soil particles. Small particles are needed as they can work their way into the soil through the aeration holes.

Determine how much of the topdressing soil amendment you will need.

Example:

Make sure all units of measurement are the same. In the case below, I will use feet as the unit of measurement.

First determine the area of your lawn.

100 ft. x 10 ft. = 1000 sq. ft.

The recommended depth for top dressing is 1/2 inch.

Convert ½ inch to feet which is 1/24 feet.

1000 sq. ft x /1/24 ft.

Divide 1000 by 24 = 41.6 cu. feet

We are not done yet………….

(There are 27 cubic feet in 1 cubic yard of topsoil.)

Divide 41.6 cu.feet by 27 cu. feet

You will need 1.5 cubic yards of topdressing soil.

Metric Calculation Example

V = Volume

V = l x w x depth  (Lawn area x topdressing depth)

V= 10 m x 10m x .0125m (read as 1.25 cm topdressing depth)

V = 1.25 cubic meters

Note that one cubic meter equals 1000 litres.

Drop the soil in small piles on the grass and begin to rake it out over the lawn. Feather it out further with a leaf rake.   You can also opt to use a fertilizer spreader to distribute the topdressing mix. Do not use a heavy lawn roller when topdressing. It will compact the lawn soil which will stifle aeration and disrupt proper drainage. If your lawn is sparse and you want to add some lawn seed, seed after laying out the top dressing. Again, more seed is not better! The grass will fill in. Water the lawn and keep it moist for 2-3 weeks until the seed germinates and begins to grow.

If you are not over seeding, water right after topdressing and leave the lawn for 10 days before mowing.

Available at Floral Acres this spring!

Pro-Mix Organic Lawn Soil -  28.3 Litres - Used for topdressing and filling in low areas in your lawn. This lawn soil is a compost-peat-humus blend that is formulated to grow grass seedlings by stimulating their root system.

Ground Keeper Fertilizer     Made in Saskatchewan

16-10-3-17-3

Nitrogen, Phosphorous, and Potassium- Sulfur and Iron

Iron strengthens lawns making them more disease resistant and greens up the grass.

Sulphur encourages lush green grass with healthy roots and helps fight weeds and diseases.

Many lawn fertilizers do not contain sulphur and iron. In my opinion these two elements are a very beneficial addition to the traditional N-P-K.