What is Hydroseeding and When Is it Beneficial

Establishing Lawn by Hydroseeding Versus Sod

Hydroseeding a new lawn
Hydroseeding a new lawn

BanksPhotos / Getty Images

Successfully establishing a new lawn depends on a number of factors, including size, timing, irrigation, type of seed, weed competition, and location. Getting a lawn established on steep slopes, hillsides, and other hard-to-reach locations can be challenging. Not only can they be difficult to access, but you are also dealing with soil erosion and washout. Hydroseeding can be a good alternative to putting down sod in these instances.

What is Hydroseeding?

In this all-in-one method, seed, fertilizer, mulch, soil amendments, straw, and other stabilizers and moisture holders are sprayed onto the soil in one shot, fed by a pump connected to a tank holding the mix.

Hydroseeding is done with special equipment, so, generally, you need to hire a professional landscaper to do it.

How Does Hydroseeding Work

Hydroseeding on a slope
Hydroseeding on a slope vadimgouida / Getty Images

The straw, sometimes polymers and similar additives making a slushy mix, keep the seed and fertilizer in place and the soil moist. If you only spread seed and fertilizer, you need to lightly rake it, roll it, and spread straw but it won’t stick to the soil as the hydroseeding mix does.

With hydroseeding, mulch is saturated with water, so it is heavier. It allows the operator to aim it like a garden hose with water yet with more distance because the hose is under high pressure.

When the hydroseeding slurry is applied onto the soil, it forms a dense mat like a blanket that keeps the seed in place. The mat retains soil moisture helping speed seed germination, and, because it sticks like glue, it is not blown off by wind or washed away by rain.

What are the Ingredients of a Hydroseeding Mixture

In addition to seed, fertilizer, and mulch, other ingredients are often added to the hydroseeding mixture.

To help to hold the other ingredients together and make the slurry stick to the soil, a tackifier is added The tackifier consists of powdered or granular glue.

Depending on the soil conditions, other ingredients can be added to the hydroseeding slurry. These include growth stimulators, fungicides, or inoculants to aid germination. Sometimes dye crystals, usually green. are added to the mix so it’s more visible where the hydroseeding slurry was applied, or to improve the visual appearance until the turf starts growing.

Fertilizer

For sites that are very difficult to access, it is better to add a slow-release fertilizer with the hydroseeding mix instead of fertilizing after the grass seed has germinated.

Soil Amendments

Before undertaking any hydroseeding, it is important that you do a soil test to find out what exactly the soil needs for successful lawn establishment. Things like lime and gypsum are common additions.

When you submit a soil sample to a laboratory, make sure to specify that you are planning to grow a lawn so that you will receive specific recommendations for soil amendments and fertilizer formulations.

Mulch

Different types of mulch are used in hydroseeding, ranging from natural materials such as wood chips, paper, or cardboard mulch, to natural or synthetic paper mill sludge. The mulches vary in price and in performance.

The longer the mulch fibers, the better the mulch stays in place, and the better the erosion control. Mulch that holds the most moisture, on the other hand, is the most conducive to seed germination. Just like with fertilizer and soil amendments, the site conditions determine which mulch will be best for your purpose.

Hydroseeding Benefits

Sod needs more watering than hydroseeding
Sod needs more watering than hydroseeding Rpsycho / Getty Images

Compared to conventional lawn seeding, hydroseeding has the advantage that it is all done in one fell swoop. Hydroseeding comes with the mulch already in the mix, which helps grass seed germination and produces a more uniform lawn.

After laying down sod, it needs frequent and heavy watering to get it established, plus mulching and fertilizing. In hydroseeding, the mulch in the mix holds the moisture so while the emerging grass needs to be watered regularly, it won’t need watering as intensely as sod. It also means that there will be a reduced loss of grass seed due to washout.

Hydroseeding slurry contains fertilizer and other soil amendments so there is no need for preparing the soil before seeding, or for fertilizing the turf once it starts growing. All in all, hydroseeding means less labor than seeding turf the conventional way, and you also get results faster.

Another advantage of hydroseeding over sod is that it allows you to grow a lawn in locations that are difficult to reach or mow, and it could work out cheaper than laying sod.

Hydroseeding Disadvantages

Because you usually have to hire a professional for hydroseeding, it will be considerably more expensive than laying seed yourself.

Sod, as opposed to hydroseeding, gives you instant results. As a home gardener, you can lay down sod yourself, all it requires is proper installation, provided that the site has been adequately prepared. 

Another advantage of sod over hydroseeding is that you have a much longer time window. The prime time for seeding grass, whether hydroseeding or conventional, is spring or fall, whereas sod can be put down during the entire growing season, even in the summer, as long as it sufficiently watered.