The City recently laid sod to our lawn to repair the damage done during road/gutter/sidewalk rehabilitation work. Please advise when it is safe to fertilize the affected area. The sod was laid ten days ago. Thank you.
Thank you for contacting the Toronto Master gardeners with your query on when to fertilize newly laid sod.
Most sod is fertilized prior to harvesting, so it usually does not need to be fertilized for at least 60 days after installation. Fertilizing before this time causes yellow patches in your lawn because the shallow root system of the sod can’t absorb the nutrients, causing nitrogen to leach into the soil. If the sod struggled to become established and was slow to root, wait to fertilize the sod until about four weeks after new growth appeared or the sod has securely rooted. Once established you may apply apply a slow release granular fertilizer with a 10-10-10 formulation.
Fall fertilizing is the most important. Fall fertilizing promotes deeper rooting and greater tolerance of winter stress, however at this time do not use a slow release fertilizer. You will want one that acts before the grass stops growing for the season. A fall fertilizer should have a lower Nitrogen (N) count than Phosphorous (P) and Potassium (K) to encourage root growth and consequently the health of the plant.
You may be interested in Landscape Ontario’s article on How to Maintain a Healthy Lawn