Next steps for grass growth after using tarp method


Hello: last year I was advised to use the plastic cover method to get rid of weeds which were overpopulating our back yard.
A few weeks ago we removed it, prepared the soil and planted seeds which are now growing. The picture attached shows approx. 10 days of growth. I have a few questions:
– does this growth seems as expected ir it is very scattered?
– is it ok to keep seeding? If so, can we step on the grass? It seems so fragile…
– what steps do you suggest to follow to make it grow more and more robustly?
Thanks SO much!


Establishing a new healthy lawn

Thank you for contacting the Toronto Master Gardeners with these important question. You have taken a good start to establishing your lawn, and now you are in the maintenance phase.

If you look back at previous postings on grass and lawn, you will see that the Toronto Master Gardeners most often recommend that gardeners transform their lawns into groundcovers. This is very good advice since a lawn is essentially a monocrop (only one kind of plant) that is vulnerable to many problems (insects, animals, bare patches, thatching, etc.) and requires a lot of maintenance and care with reseeding, aerating, enhancing the soil with organic matter and fertilizer, watering, mowing, and raking, and do not offer the pollinator insects much food.

However, many people love the pure green vista that a lawn offers, and love being able to walk barefoot in their gardens. Of course, a nice large lawn also gives children a lovely open area to play, which is also very appealing. Below, I offer the basic care that a lawn requires to keep it healthy and thriving.

However, to answer your direct questions. After only 10 days, your germination seems healthy. The day before the next rain, you can add some more seed to the bare patches with a very light covering of compost. You can walk on the grass to do this reseeding, but wait for next year before you walk on the lawn regularly. How to make your lawn strong and healthy, will hopefully be answered in the following:

Weeds – By preparing your soil by placing black plastic on the previous weedy lawn, you have created a good canvas for your new grass seed. For those who object to using black plastic that is totally unrecyclable, a heavy layer of paper and cardboard over a growing season works as well, if not better, to smother anything that is growing on the area. As your new lawn gets established, pull out the new weeds that you see.

Aeration — The first step in improving your lawn is aerating it, to open the surface of the soil creating space for the penetration of air, water and nutrients.  If your lawn has more than 2.5 cm of thatch, de-thatching in spring will also allow more water and nutrients to reach the roots.

Soil – All gardening starts with a good soil with a high organic matter. I am sure you spread a layer of good quality top soil consisting of loam, peat moss and compost before you seeded. I hope you spread about 1”-4” depending upon how depleted your original soil was before you sowed your grass seed. Moving forward, if you are enhancing an existing lawn, you would spread about ¼ – ½” of top soil so that you could still see the existing grass. This is what you should do every spring.

Reseeding – Reseed as often as you see bare patches in your lawn. Cover this seed with a very light layer of compost. Reseed when you know that it will be raining soon.

Sunlight – In general, lawn grows best in full sun, but there are now grass seed that are shade tolerant.

Watering — Water early in the morning when temperatures are lower reducing evaporation and winds are generally calmer. Especially at this early stage, make sure the grass does not get stressed by not having enough water. On the other hand, if there has been a good rain, do not water the lawn for two or three days following the rain. You do not want to have a water-logged root system. Make sure the grass gets plenty of water until it has grown enough to have had three mowings. From that point on, water the grass with the normal schedule for the area, the current weather, and the type of grass.

Fertilizer — Regular fertilizing also provides valuable nutrients to grass. A light application of fertilizer can be applied to the new seeding approximately 4-6 weeks after germination. There are many specifically formulated fertilizers for turfgrass and if applied according to the instructions, will promote a thicker, healthier lawn.

Mowing — Make sure your lawn is mowed correctly with a sharp blade and not too short.  Taller (about 3 inches) grass conserves moisture better, improves competition from weeds and reduces the effects of summer droughts. Mowing frequently to cut no more than 1/3 of the length of the shoot is also best.  Keep the grass clippings on the lawn to return nutrients to the lawn and act as a natural mulch. Since your lawn has just been established, I would not mow the lawn until you are confident that the grass blades are strong enough to tolerate being walked on and can support your weight and the weight of the mower.

Just as an aside, it seems that the “NO MOW MAY” movement that recommends that you do not mow your lawn in May, is receiving a lot of push-back from the lawn experts, who recommend that you do mow your lawn if it is needed. This advice comes from the Guelph Turfgrass Institute: 

Walking on your new lawn – Avoid walking on the lawn for quite a while until the blades and their roots are much stronger. It’s also a good idea to pull new weeds as they emerge to prevent them from spreading.

For more information, please consult the following:

Here is a good previous posting from the Toronto Master Gardeners on enhancing an existing lawn:

Landscape Ontario has some excellent information on lawn care that you may want to consult.

The Ontario Ministry of Agriculture and Food also has a lot of information.