“Lawn composting” follow up query


For the 400 square foot lawn space, how are the grass roots stressed by composting? My biggest concern was smothering the plant by using too much compost, when I do schedule composting. An aggressively pruned city European Beech tree has been absorbing much of the hydration on a 400 square foot lawn, not including the 50 square foot space the tree has claimed. I’m trying to contain my enthusiasm around stressing the established lawn any further. I could easily water the lawn after a light sprinkling of compost.
Also, how is compost ideally stored, since I know it will settle and clump for early fall in the containers? If I harness my pent-up pandemic enthusiasm, by
covering the compost in a garage, since “out of sight is out of mind”, I can deal with it then. It’s hard to believe fall is only 70 days away, so weeding looks like it’s on the agenda with all this rain.
Thank you


Thank you for your great lawn top dressing questions. I am wondering if you are planning to compost your lawn because its growth has slowed and its colour is fading, or because you would like to give it some more nutrients because it is competing with a large tree ?

Living in the west end of Toronto, it is likely that you have sodded, or seeded, the area with a cold season grass mixture. Common blends in Toronto contain Kentucky bluegrass, perennial ryegrass and fine or tall fescue.

These grasses sprout new growth in the spring when temperatures reach around 18 degrees Celsius. They continue to grow until temperatures warm up to about 27 degrees Celsius, when the grass begins a phase of dormancy. The colour fades and you will notice that you don’t need to mow as often. The roots are still alive and require about one inch of water per week to stay healthy.

When the cooler weather returns in late summer or fall, the grass begins another growing phase and will appear noticeably greener.

If you would like to give your lawn a nutrient boost, mid September is the best time. The weather has usually cooled and the cool season grasses are in a growth phase- and actively seeking nutrients.

For best results lawn care professionals recommend: 1. aeration- to increase the amount of water and nutrient that reaches your grasses roots. 2. dethatching with a rake to remove any built up clippings or leaf litter. This helps to prevent disease carrying spores growing, as well as allowing your aeration to be more effective. 3. Topdressing any patchy areas- where the grass coverage maybe sparse, with about half an inch of fine, light, sweet smelling compost. In areas that are healthy and thick, add about a quarter of an inch of compost. Rake the compost, like the guy in the video you posted recommended. Take care to allow the grass leaf blades to show through so that they are exposed to sunlight.  4. Overseeding, to fill in the patches.

Unfortunately, City of Toronto compost is not ideal for lawns as it is not fine enough, and is made up of domestic garden waste collected from around the city. This means it may contain weed seeds, chemicals that have runoff hard surfaces into gardens, waste products such as building materials and plastic waste. It is often heavy and smells, which means it hasn’t had enough time to decompose.

Check your compost for weight and smell. If it’s heavy it needs time in a pile somewhere not too conspicuous in your garden, so that it can continue to decompose. Water, air and heat from the sun will do the work for you.

If your compost is already lightweight, I would use it around your garden beds, under your mulch if you have any. It will give your plants a boost next year, and if you mulch over the top you will suppress many of the weed seeds.

Storing the mulch in containers in your garage is not advisable, as it is unlikely to get good air circulation- essential for healthy compost. This encourages anaerobic bacteria to grow, which can kill off the air loving bacteria that we like to see in healthy soils.

You can aerate it if you are keen, but this would require storing it in breathable fabric containers and turning and mixing within the containers at least once a week, which can be heavy, messy work. You would also need to check the moisture levels in the containers to make sure the mixture doesn’t dry out completely.

If your budget allows, put your city compost on your garden now and in the middle of September, buy some bags of fine compost, which will be a light, consistent, well rotted mixture. If you are top dressing for a nutrient boost, at a quarter inch thick over 400 sq feet of lawn you will need 8.5 cubic feet of compost. Check the coverage on the bags, as most contain several cubic feet per bag.