Hydromulching

Hydromulching is the industry standard for restoring the productivity and health of damaged and depleted soils. This innovative and effective process mixes a slurry of water, seed, fertiliser and fibre mulch. It also includes a tackifier, which is a kind of bonding agent that holds the slurry together and allows it to stick to the surface of the depleted soils when sprayed.

The slurry is operated and directed by a contractor who uses a hydromulching machine. This machine is generally a spray cannon, referred to as a ‘boom’, affixed on top of a truck for easy mobilisation. The distance and amount of slurry these booms can spray varies depending on the model, but the distance averages over 100 metres. The large spray distance of the boom makes hydromulch seed mix particularly effective for large-scale, emergency vegetation projects, as the slightest exposure of the soil to wind, water and sun can cause further erosion.

If you’re unfamiliar with the process, you might think that hydromulching and hydroseeding are just variations of revegetation strategies. For a layman, that might be true as both hydromulching and hydroseeding are highly effective methods of rebuilding the health of soil.

A hydromulching machine can reach into difficult areas and spread slurry across large areas in less time than other methods like hand seeding, drill seeding or sod applications. Generally, both hydromulching and hydroseeding techniques result in a much thicker and healthier vegetation.

However, there are some key differences between hydromulching and hydroseeding:

• Hydroseeding relies on water to carry seed and fertiliser onto the soil.
• Hydromulch seed mix, on the other hand, adds wood fibre or fibre mulch to act as a cover for the seed.
• The addition of the fibre mulch helps the slurry retain moisture, which means faster and more uniform germination and growth.
• The fibre mulch also plays an important role in protecting the soil from erosion, animals and water erosion caused by rain. This is especially important if the soil in question is more prone to run-off from sitting on a slope.
• Hydromulching services rely on the same type of equipment as hydroseeding.

In Australia, the cost of hydromulching varies depending on a few factors. These include:

• Size of your property or planting area
• Seed type you choose based on your soil type and growing conditions
• Seed density
• How prepared your soil is for slurry application — for example, if the ground requires additional topsoil or grading, this will increase your hydromulching costs

It is important to note that larger projects can cost less than smaller projects, causing little difference between residential and commercial projects. Why is that? Well, in terms of fixed costs, hydromulching services still take the same amount of time, expertise and equipment to perform a project of any size. If you have a larger area to cover, it distributes the hydromulching costs so it may work out to be cheaper.

The average cost to hire hydromulching services can vary between $0.06 and $0.20 per square foot of land. The cost sits between $2,000 and $4,000 per acre. However, if you have less than an acre of land, your contractor might charge you by the hour instead. In this case, their professional rate applies and you may pay between $24 and $30 per hour.

Even though hydromulching services are more involved than hand planting, the results are far better and consistent. Hydromulching also follows the climate conditions for spring and autumn planting for successful revegetation.

Here are a couple of ground rules for revegetation using hydromulch seed mix:

• The best time to plant is during autumn as the slurry mixture has time to adhere and the seeds gain energy in the soil for a successful germination phase in the spring.
• However, it is fine if you’re also hydromulching in the spring! Just make sure the ground temperatures are between 18 and 23 degrees Celsius. They should stay this way for at least six weeks after hydromulching. That’s why it’s so important to get the timing right.
• The uniform application of a hydromulch machine results in the vegetation taking just 5 to 7 days to start sprouting (given the right temperature conditions, of course). You’ll need to keep a close eye on the growth and care for the soil over the next several weeks.

Seedbeds need constant moisture, so you should watch the weather. If there’s rain in the forecast, you get a free pass! Temperature matters, too — if it hits 29 degrees Celsius and there’s humidity, avoid watering your seedbed because this could lead to fungus. Shady areas of your property need a longer time to dry the mulch before you can water again.

Your grass seed growth should reach about three inches in the first month. Plan to mow down to about one and a half inches. After the first mow, you can taper off the watering frequency to one to two inches of water per week.

Yes, you can absolutely hydromulch your own lawn, but keep in mind that a hydromulch machine can cost between $1,500 and $3,000 to purchase. There is a lot of testing and preparation involved, where you may need to further treat your soil to get it ready for hydromulching.

That’s why hiring a hydromulching service is far more affordable than DIY hydromulching. It can save you time and money that you might otherwise waste on unforeseen issues.