Confusion Sets In

May 11, 2007

Last night I went to a free City of Ottawa seminar on organic lawn care. This is what I learned:

Compost for Your Lawn

The city has municipal compost for sale at their Trail Waste Facility. The prices seem pretty good and the compost is okay to use as it has gone through five stages of high heat that has killed off any potential weeds. I’m thinking of picking some up.

You can also use manure on the lawn as long as it has been aged and pasteurized so that the nitrogen doesn’t burn the grass.

Used coffee grinds are also a good fertilizing treatment for your lawn. It has an NPK rating of 4-1-3 and you can call your local coffee shop to pick them up in bulk. They may even have a waiting list that the shop cycles through each day.


If your grass is growing, you don’t need to core-aerate.

If you core-aerate in spring, it’s best to do it in early May. Be sure to rake up the cores of you will have a lumpy lawn. You will need to top-dress the lawn with compost ASAP so that the grass roots don’t dry out. Make sure the layer of compost is no thicker than your little finger or you’ll suffocate the grass.

It’s better to core-aerate in the fall when the days are warm and the nights are cool. This way, you can wait a weekend before you top-dress.

Grass seeding

Grass seeds like to germinate when the days are warm and the nights are cool, so preferably in fall. If you have to put it down earlier, do it in spring. Buy premium grass seed and check to see if there is a weed count (1% or more is no good). After you’ve spread the grass seed, press it down into the lawn with a board to ensure good contact between the seed and the soil or you can use a roller. Grass seed takes three weeks to grow.

Rye grass germinates quicker than Kentucky Bluegrass. Kentucky Bluegrass is actually from Mongolia and turns blue as it goes dormant.

Don’t over-seed a healthy lawn.

For deep watering in the spring and fall, water the grass 1″ once a week. Use a soaker hose spread horizontally halfway down your lawn from your house. Turn the hose on a low flow at night before you go to bed and remember to turn it off in the morning. Be sure that no water has drained off the end of your property – if it has, reduce the flow of water. Using a trowel, dig down into the end of your property to see if the lawn has been watered at least 1″. Adjust your low-flow accordingly.

In the summer, use an oscillating sprinkler at the highest heat of the day and water 1/8″ to ¼” to drop the temperature of the grass blades so the grass won’t go dormant.

The shorter you cut the grass, the shorter the grass roots will be.

Corn Gluten Meal

Corn gluten meal (CGM) is both a pre-emergent herbicide and a natural source of nitrogen fertilizer. It inhibits the germination of ALL seeds so it’s not a good idea to apply it when you are trying to grow grass. CGM comes in a fine yellow powder or a golden pelleted product. The pellets are better as they are easier to apply and are effective up to 6 weeks.

Apply CGM three times a year: from mid-April to mid-May to control the germination of weed seeds from the previous fall, in mid-August to mid-September to control the weed seeds that blow in late May and in mid-September to late October to prevent weed root systems from establishing before winter.

There’s a lot of references out there that says you should not use CGM after the forsythia blooms, however, only use this guide if you are trying to control crab grass. You can still use CGM until mid-May to control dandelions. It is better to get the CGM down on your lawn sooner as it becomes more effective as is decomposes. CGM depletes phosphorous in the upper layer of grass and the protein stops root growth.

Turf Maize is the patented CGM supply in Canada, however, it is the same product as you would get at any coop or feed store. It’s also cheaper.


Don’t buy pine bark nuggets as your mulch for the garden as all the nooks and crannies provide the perfect shelter for earwigs and slugs. Composted pine mulch is much better.


The nematodes that you get at garden centres are used to kill insects, like white grubs, in your lawn. These are microscopic worms that attack and kill insects by entering the insects’ body and releasing bacteria, which kill the host in several days. They then feed on the body and reproduce inside of it. There are two kinds of nematodes in the package that you get from the garden centre: steinernema and heterorhabditis. Steinernema is an “ambush” nematode and waits in one spot for suitable insects to move close to it. They like a soil temperature of a minimum of 15° C. Heterorhabditis nematodes are “cruiser” killers that go in search of insects and are really effective against sedentary white grubs. They like a soil temperature of 18 – 20° C.

Keep in mind that the white grub damage that you see in spring actually started last fall.

Here’s how to handle and apply nematodes to your lawn:

  • Buy nematodes from a garden centre. They will be located in a sponge in a bag in the fridge.
  • Open the bag and take a whiff. A bad smell means that they’re decaying and no good.
  • Take them directly home and put them in your fridge.
  • Remove thick thatch from your lawn and ensure there is no high nitrogen, herbicide or fungicide has been applied recently
  • Ensure the soil is moist, not wet.
  • Open the bag and put the sponge in water. Don’t let the sponge sit in water for more than 2 hours or you will drown the nematodes.
  • Apply to the lawn using hose-end sprayers, watering cans or small-pressure sprayers. Make sure you don’t have a small-holed screen on your hose, as the nematodes will be filtered out.
  • Apply nematodes in the morning, dusk or on an overcast day as they will be damaged if exposed to UV rays. Increase the rate of application of nematodes if you are trying to combat white grubs and your box of nematodes contains steinernema nematodes. This type of nematodes is ineffective in killing white grubs.
  • Once applied, wash the nematodes down into the grass layer with a hose.

Ants in the Lawn

Too many ants in your lawn will damage grass roots and dehydrate the soil. Ants like hot and dry soil so be sure to water the area where they are present as well as put down coffee grounds or organic compost. To get rid of the ants you need to kill the queen. Diatomaceous earth takes a long, long time to be taken into the colony to the point where it may touch the queen. It’s better to use Borax-based baits.

To make Borax-based bait:

  • 1 tablespoon sugar
  • 1/2 teaspoon Borax (the stuff you add to your laundry)

Mix together and put in a small plastic container with a lid and small holes on the bottom.

So, Now What?

After talking to the presenters, here is my NEW plan of action:

  1. Spread corn gluten meal ASAP.
  2. Weed the dandelions with a digger on an on-going basis, preferably after it has rained.
  3. Spread coffee grounds and compost to increase the organic matter of the soil.
  4. Water the lawn 1″ once a week with a soaker hose overnight.
  5. Spread corn gluten meal in mid-June.
  6. Water the lawn 1/8″ with a sprinkler at the highest heat of the day.
  7. Spread corn gluten meal in mid-August. Check to see if the bare patches have grown in with grass.
  8. If not, at the end of August, top dres the lawn with compost or bagged topsoil.
  9. Spread grass seed.
  10. Water the lawn 1″ once a week with a soaker hose overnight.

I got a lot of printed material from last night’s seminar. I plan to go through them over the weekend to see if there’s anything I’m missing for my situation. For more information I can call the Avoid Chemical Pesticides hotline at 613-724-4227. I’ve already left a message in hopes of answering these questions:

  1. Should I put down compost first and then put down corn gluten meal to help cover up the 10-3-3 fertilizer that I’ve already put down?
  2. If coffee grounds have an NPK value of 4-1-3, won’t that interfere with the effects of the CGM?
  3. How ineffective will the CGM be since I’ve already put down 10-3-3 organic fertilizer? Should I put down more CGM for this spring’s application?

When I went to Make It Green, I thought I had a plan. I put down organic garden soil and fertilizer as I was told that I was already past the window of opportunity for CGM. Now I’m told that CGM is still effective now against dandelions and that you need to put it down sooner to fight crabgrass.

See? Confusion. I want to kill those greedy dandelions and also those insufferable ants. Can my two desires work together? I’ll let you know.

2 Responses to “Confusion Sets In”

  1. Catherine Says:

    You take great notes at these classes. Thanks for taking the time to post them.

    Corn gluten meal works on the roots. The seed sprouts but the roots are prohibited by the protein in the meal from taking up water. So, I’ll be interested to hear what they say when they return your call.

    CGM’s effectiveness is lessened by soil moisture and microorganism activity. So, I’m thinking that watering in the organic fertilizer will increase soil moisture and the fertilizer will increase microorganism activity. These factors will decrease the herbicidal effectiveness of corn gluten applied either before or after it.

    However, I’m wondering if this isn’t offset by the long-term effects of CGM. It takes several years to get a good control.

    Hope you post with what the hotline answer is.

  2. Kathy Says:

    Thanks Catherine! It was a really good presentation and I learned a lot from the instructors. They did give out handouts that had loads more info than what I’ve written here. Email me if you need anything specific.

    I did get a call from one of the instructors and I’ve written about her response here.

    I have heard that CGM takes a few applications before your lawn starts visually responding. I’ve still got half a bag of CGM to use for the summer and fall applications so I’ll see how it goes.


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