Hydroseeding – What’s Up with the Weird Green Stuff?

protecting environment in BC

Passing through new construction, you may have noticed an odd greenish-grey-coloured coating, alongside the road.

What is that weird-looking stuff?  And why is it there?

The answer is – hydroseeding – a mix of grass seed, mulch, fertilizer, water and a few ingredients to make all that stick together. (The mulch is coloured with a natural and biodegradable green dye to help see where the product has been applied.) This concoction is sprayed on newly excavated or filled slopes to give them a head start to re-vegetation.

hydroseeding bridge
Hydroseeding helps stop sediment from running into waterways.

The special slurry forms a blanket on bare soil, protecting the soil from erosion and runoff, and holding the seed in place until it gets growing.  The seed is a specially designed mix that is unappetizing to wildlife (animals grazing roadside can mean danger for both them and vehicles), grows quickly and forms a healthy root mass. Hydroseeding is a preferable to other erosion control techniques like traditional broadcasting or sowing of dry seed, because the mulch and tackifier (binding ingredient) hold the soil together while the seed is growing.

It’s important to keep sediment and debris from running into streams, creeks, lakes and the ocean.  Vegetation beside highways is also critical to absorb some of the moisture from rain, snow and ice, which could undermine and damage the road base.

Another method we use to prevent erosion and revegetate bare earth are erosion control blankets. Seed is first distributed on the soil, and then the long fibre mats are manually rolled out on top, and staked to the ground.  This method is used in areas prone to slope erosion, or when there are environmental concerns that heavy rains could transport sediment into sensitive areas.

hydroseeding and slope protection
Erosion control blankets were used here, due the slope’s steepness.

Each year, we cover more than a thousand hectares with hydroseeding, as part of our construction and maintenance projects. For example, hydroseeding was sprayed on about 20 hectares alongside the Malahat Highway, on southern Vancouver Island, in spring and fall 2017, and fall 2018.

In 2018, we also invested in hydroseeding on roadsides in the Southern Interior that were impacted by wildfires, to help prevent erosion and stop invasive plants from taking root.  Across BC, hydroseeding is part of protecting water quality and sensitive ecosystems next to our highways, as well as halting the spread of invasive plants.

hydroseeding greening
Hydroseeded area greening up nicely, along the Malahat Highway.

So, the next time that you see slopes looking like they’ve been slathered with off-putting hospital-green colour paint, know that the area will soon transform to good-looking ground cover.  As the grass grows, weird green will give way to verdant natural beauty that protects ecosystems and highways.

Do you have a question about the work we do?  Ask us on Tell TranBC.

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Page 1 of 35 comments on “Hydroseeding – What’s Up with the Weird Green Stuff?”

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    • Hi there, Roy. We can’t say how the seed will perform in southern climates, such as Florida. We encourage you to reach out to a local company in the US to chat further about it. Hope this is helpful.

    • Hi there Ted – thanks for your question. Unfortunately, we aren’t the experts in the green stuff exactly – we have just shared our story on how and why we use it along BC highways. If you have questions regarding personal use of the spray in your yard – we encourage you to reach out to a local hydro seed company to see if they can help you. Hope that this information is helpful. Good luck!

  1. Well it seems like you haven’t got too many answers that are specific as per usual with any government agencies just your typical blah blah blah why even bother if people ask a question they expect a damn answer you should have all the ins and outs on your products slash whatever you’re doing maybe not 100% but at least more than 20 later

    • Hi Nick – thanks for your question. Unfortunately, we are not the experts on the topic. Perhaps you could research efforts to restore local ecosystems in the Sahara (if that’s even a thing?).

  2. I am wanting to know the exact ingredients of this. My concerns are:

    Is the seed itself treated – as is often the case these days – with anything? Many companies are now using treated seeds and soil for plants.

    What are the “other ingredients”? I would like to know the specific chemical contents, as well as the source of such items as “fertilizer” and “mulch” and “coloring.”

    Too often companies glide over the actual ingredients and the users assume they are safe because they are told they are, so concerned buyers need to have access to the specific contents and the contents’ specifics.


    • Hi there Judy – as the mix (or slurry) is comprised of water, seed and fertilizer – the only side effect might be the growth of grass where it wasn’t intended (on the tree for example). Hope this is helpful!

    • Great question Morley – unfortunately we don’t have that information available as we hire contractors for this service. We suggest you conduct a google search for hydroseed in your area and reach out to those business who offer it locally for more information. Hope this is helpful!

    • Hi there LT. Thanks for your question. A quick google search indicates that the application shouldn’t cause any concerns. Our contractors are also required to follow our environmental best practices, to reduce any harmful impacts to the environment during their work. The application is wet when applied and the slurry is made to stay in place once applied. If you are concerned, we encourage you to make sure your windows are rolled up if you drive through an area. We hope that this information is helpful.

  3. I would appreciate your advise on the best grass to plant in the north east of p.a. that will discourage wild animal from destroying my lawn along with some shrubs. Thanks

    • Hi there Winston – thanks for your comment. Unfortunately, we aren’t the experts in types of grass to plant in your area. We are the ministry responsible for transportation in British Columbia. That being said, we are certain that someone in your local area (perhaps a garden centre) would be able to give you some tips on this topic. Good luck!

    • Good morning Shirley – thanks for your comment. Are you asking if there were flaggers on site during this activity? I believe the road was not yet open at the time.

  4. Also cool is that the mix is custom for different regions of. In their construction contracts, the Ministry will require a “Kootenay mix”, for example, and direct you to their Standard Specifications for Construction.

  5. Someone doing the hydro-seeding has used a concoction with Spear Grass seeds – now all dog owners must beware the huge vet costs when removing those spears from dog noses/skin, etc.
    Please check – Do Not Use Speargrass in your sprays, please.

    • Hi Lawrence,

      Thanks to alerting us to this situation.

      We’d greatly appreciate if you could let us know where you saw the speargrass growing among hydroseed.


  6. The green color is strictly for application purposes and usually the color fades away quickly when exposed to the sun. Though I do agree it could be a bit closer to the real thing.
    Both Emil Anderson Construction and the Ministry were fantastic to work with. The 2017-18 Malahat Upgrade was a great start for our new much larger capacity Hydroseed unit.
    Any further questions or your interested in having hydroseed done on a project big or small. http://www.islandirrigation.ca

    • Hi Fred,

      Thanks for asking about contract work with us.

      I recommend that you monitor BC Bid. Also a lot of hydroseeding work is done through subcontracts with the larger construction companies, so you may want to reach out to them, as well.