It’s Spring Tune-up Time For Your Lawn!

by Gail Cocker, Master Gardener In Training, SCMG.

The days are longer, the sun feels warmer and you are itching to get out in your yard.  Your instincts are correct; a few spring maintenance tasks will help ensure that you have a lush, green lawn this summer. However, go gentle!  The spring is a delicate time for your lawn… the soil is still spongy, the grass is tender and there is a good chance we may yet see another snowfall.  Here are your spring tips and why you should bother!

Avoid walking on your lawn and doing heavy yard work in early spring when the soil is still wet to avoid compacting the soil. Grass does not like compacted conditions because it makes it harder for water and nutrients to move through the soil and for roots to grow. Do not be tempted to level out your established lawn by using a weighted lawn roller as this will further compact your soil.   Lawn rollers are for laying sod. While you wait for things to dry out sharpen your mower blades if you didn’t do this last fall! Once your soil is dry give your lawn a gentle rake and remove any debris that will smother the new grass such as leaves, evergreen needles and dead grass.  You can spread out any remaining snowdrifts to speed up melting.

If your soil is compacted, or if you have noticed poor drainage on your lawn , (perhaps due to high clay content),  it is a good idea to loosen it up by doing a core aeration.  Core aeration is done by a machine which removes plugs of soil from the lawn creating channels for air, water, nutrients and top-dressing material to penetrate the soil.  Aerating your soil provides multiple benefits such as creating space around roots so they can exchange the gases and absorb water and nutrients.  If water can enter the soil then less water will run off the surface and potentially erode the soil. Even if your lawn isn’t compacted it is a good idea to aerate your lawn every 2-3 years as the turf will respond favorably to this with increased shoot and root growth.

The best lawns are ones that have healthy soil. Start first by doing a soil test to find out what nutrients are available to your grass over the growing season. Nitrogen, (N), is the most important nutrient for your lawn as it helps the grass produce green healthy leaves. Phosphorous (P), is important for strong root growth however, more so for newly seeded lawns.  Established lawns have good root systems that can scavenge phosphorous from the soil so typically do not need additional phosphorous. Potassium, (K),  helps your grass overcome heat and drought stress and so you want to see if your soil test reveals a deficiency of this nutrient. You can have a professional lab do the testing for you or there are “do it yourself” tests available in most nurseries.  However you choose to do a soil test, it is recommended that you take quite a few samples of soil from all parts of your lawn to work with a representative soil sample from your yard.  

Spring is a good time to get a jump on weed control by hand digging out any dandelions or crab grass you see emerging.  If you have a severe weed infestation you may want to apply a “pre-emergent” weed herbicide. By applying weed control early you are more likely to stop weeds from taking hold.  The downside of this strategy is that you will not be able to apply grass seed for 30 days.  So take a close look and make a choice; herbicide or top seeding?

A good way to improve your soil is to add a thin layer (1 cm) of topsoil or compost, (“top dressing”) each spring.  As this organic matter breaks down it mixes with the existing soil and adds nutrients, improves drainage and drought resistance with higher water-holding capacity.  Adding organic matter will improve sandy soil by binding the sand particles together and improving the water and nutrient holding capacity of sand.  If your soil is predominantly clay then the addition of organic matter will loosen up the clay leading to improved aeration, water penetration and better drainage . Top dressing with compost also reduces the need for fertilizers.  Topsoil and sifted compost is available from landscape supply yards in bulk, or you can buy smaller quantities of  “lawn soil” in bags from your local nursery. You can make your own top-dressing using a mix of 1/3 sand, 1/3 loam or topsoil and 1/3 peat moss.  Depending on your soil, amend the mixture appropriately, ie if you have sandy soil reduce or leave out the sand, if you have clay reduce or eliminate the loam. 

Once the temperature is consistently above 15 degrees C (soil above 10 deg. C), grass seed will germinate, so now you can apply grass seed directly onto the topsoil.  This is a good time to introduce drought resistant grass such as perennial rye and fescue.  If you don’t mind the white flowers in your lawn, white clover will naturally add nitrogen to your soil.

Once your grass starts to grow you can start mowing it but be sure to leave it at least 3” high.  The best practice is to mow more often so you can leave small pieces of grass clippings on the lawn which will provide a natural source of nitrogen and increase the organic matter in the soil.

Depending on the results of your soil test you can lightly apply a Slow Release fertilizer in the late spring.  Too much fertilizer will boost new growth, which will struggle in the heat of the summer.  Ideally you should fertilize in late fall when the grass is fully established and growing again after the heat of the summer, so make a note to do this later this year.   Apply a fertilizer mix that is consistent with what nutrients your soil test indicated were deficient.  A Slow Release fertilizer releases the nitrogen more slowly over a longer time period. This makes it less likely to burn the grass and often produces a more uniform green colour over a longer time period.   All natural fertilizers (manure, bone meal, etc) are Slow Release as they require the soil microbes to release the nitrogen in a form the plant can use.  Synthetic fertilizers have a higher nitrogen content than the natural fertilizers and you will require a lighter application… read the directions on the bag carefully.

Congratulations! You are done and can be sure you will be rewarded with a lush and green lawn this summer. Come Summer you will be busy with weed and pest control, mowing and water management. Consistent annual spring improvements to the soil will guarantee improvements to your grass performance.   Further information on lawn maintenance can be found from  OMAFRA Fast Facts on Lawn Maintenance at

Month By Month Guide to Spring Lawn Tasks

Once the soil is dry Walk around and take a look at your lawn to see how it fared over the winter  
  Sharpen lawn mower blades To reduced tugging on the roots of the grass
  Gentle rake to remove debris  
  Spread out any remaining snow drifts  Speed up melting
  Aeration (remove plugs of soil) Every 2-3 years or more frequently if your lawn in compacted. Will loosen compacted soil and allow water, air and nutrients to penetrate deeper leading to stronger roots and increased shoot growth
  Take 10-12 core samples of soil for a soil test Find out what nutrients your soil needsIf your soil is acidic you can add lime in the spring… just wait 30 days before seeding.
  Hand dig out weeds such as dandelions and crab grass or apply a pre-emergent weed control herbicide NB It is either applying a herbicide OR over -seeding *to fill in bare spots
LATE APRIL Top dress with topsoil or compost, no more than 1 cm deep Improve your soil quality and structure
  Water well To let the soil settle and identify any low spots
Once the air is above 15 deg. C and the soil is above 10 deg. C Overseed with grass mix* At least 1 month after applying herbicide or lime
MAY Mow grass – not shorter than 3” and leave clippings on the lawn To provide a natural source of N
  Lightly apply a Slow Release fertilizer  Based on the results of your soil test and 30 days after overseeding
  Water Management;  no more than 1” per week in the growing season Usually watering not required in spring
  Make a note in your calendar to apply fertilizer in late October, early November