Hydromulch Vs Hydroseed: What Is The Difference?

Hydromulch and hydroseed are sometimes used interchangeably, and there’s not really much of a difference between the two words. They both refer to the method of applying green seed slurry that lawncare professionals and homeowners may apply to bare soil to grow new grass. There are, however, situations when one word might be the right choice over the other.

Why Does Hydroseed Have So Many Names?

Hydromulch, hydraulic mulch seeding, and hydroseeding all refer to the same seed-sowing technique. However, when you purchase hydromulch or hydraulic mulch, it usually doesn’t come with the seeds that make the final product: a hydroseed mixture.

Seeds are purchased separately and mixed with water and the slurry product at the time of application. Hydromulching and hydroseeding, then, is the method of applying the slurry of seed and hydromulch, using it to grow a new beautiful lawn.

What Is Hydromulch Made Of?

The hydroseed slurry is a mixture of grass seed, fertilizing nutrients, mulch, and a solidifying agent like paper pulp or a biodegradable synthetic binder. The solution coats the surface of the soil and sticks like tack, providing the grass seeds with stability and a high level of nutrients that stimulate germination and grass growth.

What Is Hydromulch Used For?

The firm and absorbent nature of the slurry makes it an additional support to regular watering, which still needs to be done regularly. Hydromulch should only be applied directly to exposed soil and can’t be used to overseed a lawn. It’s best used when seeding a large area or section of a lawn or for spot-seeding thin or bare spots in an existing lawn.

In general, hydromulching is good for:

  • Supporting grass growth – The nutrients, moisture retention, and protective structure that the hydromulch solution provides is a great support to seeds as they grow. If seeds dry out during germination, the process fails in some seeds, and the germination rate is lower than seeds that remain moist for the few weeks that they need to sprout.
  • Speeding up grass growth – A hydromulch mixture includes fertilizer and organic material that deliver more than enough nutrients for them to grow, which, in addition to a consistent availability of moisture, allows the germination process to speed up. Once it reaches the seedling stage and blades emerge, however, the grass will grow at the normal rate for its species.
  • Planting in hot and dry areas – Hydromulch creates a sponge-like consistency that holds moisture and prevents seeds from drying out in open air and sun. Hydromulch is one of the best ways to get grass established where it’s hot or dry, and once the roots are established, drought-tolerant species of grass will be able to survive on their own.

Planting on sloping land – The solid hydromulch structure keeps seeds in place on land that slopes, helping the seeds stay in place on uneven ground: bare seeds might themselves be rinsed away with rain or watering as gravity does its job. Soil erosion affects steep slopes particularly easily and can be prevented by planting grass with robust root systems that hold it in place.

How Does Hydroseeding Support Germination?

Grass seeds need light, water, and nutrients to grow into a full green lawn, which they normally get from the soil and regular watering. When you use a hydromulch to apply the seeds, they’re protected from birds and squirrels, as well as from being washed away with rain and watering. They’re also protected from drying out since the absorbent material holds moisture between waterings.

Water is essential for the seed to sprout: since seeds don’t have leaves and can’t make energy from sunlight, it relies on water to deliver nutrients and moisture so the grass embryo will swell, break out of its shell, and set roots down into the topsoil to then grow grass blades above ground.

Should Soil Be Prepared Before Hydroseeding?

Preparing and Leveling Lawn

Hydromulch needs to be applied directly to exposed soil so the seeds will have contact with the ground to reach their roots when the time comes. The ground should be tilled or core aerated before applying the mulch, so there is air and space in the topsoil for the roots to establish.

Porous soil also allows for moisture to drain, be absorbed, and deliver nutrients to the grass seedlings as they mature into a full lawn. Adding fertilizer like granules or compost also helps prepare the soil for when the hydromulch breaks down, and the grass starts to rely on the ground for nutrients and moisture.

How Often Does Hydroseed Need To Be Watered?

Watering hydroseed regularly is essential for the grass to grow properly: it needs to be watered as much as when seeds are planted directly in the ground. The material doesn’t substitute for having to water, and it will dry out if not watered two to three times a day, depending on the weather (if it rains, you can wait until it starts to dry out to water it again). The nutrients and protective material won’t do any good if it isn’t wet enough for the seeds to remain moist and be able to receive the nutrients.

Hydromulching isn’t necessarily less labor intensive, but it does support a higher germination success rate when planting grass seed. When it’s watered regularly, the hydroseeding method supports fast, healthy growth throughout germination and sprouting.