Roadside Revegetation

IMPLEMENTATION GUIDES
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Storage Area – The contractor will want a site to store hydraulic mulches, tackifiers,
fertilizers, and other materials associated with the hydroseeding operation. The site
should be in close proximity to the hydroseeding areas and relatively safe from vandalism.
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Equipment – If specific types of hydraulic seeders are required for the job, they should
be specified in the contract. Using hoses to access portions of the project site will often
be necessary. The contract should specify how many feet of hose are needed and what
percentage of the project will be applied by hose.
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Cleaning Equipment – The contract must state that the tank and hoses will be cleaned
from all previous hydroseeding or hydromulching projects. The equipment will be
inspected and, if it does not pass inspection, the contractor will be required to clean
equipment at an approved offsite location.
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Weather Conditions – The weather conditions, based on manufacturer specifications,
should be stated. The contract should specify acceptable temperature ranges and wind
velocities. It should also state whether rain or freezing temperatures can occur within
a specified period after application. A provision should be stated that applications will
not occur on frozen ground. Some tackifiers also require that the soils be moistened
before application.
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Mixing – The contract should state that the seeds be mixed into the slurry immediately
before application. It should further state that the slurry must be applied within 30
minutes after the seeds have been placed in the tank. When the seeds are in the slurry,
it should be moderately agitated only enough to mix the seeds and keep the slurry
from separating.
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Application – The slurry should be applied at a rate that covers 85 percent of the
soil surface. Slurry should not run off the soil. If it does, adjustments to application
speeds or nozzles must be made. Figure 10-101 shows the spray pattern of two types
of nozzles. Avoid applying slurry at a range that causes slurry to splash off the surface
and soil to dislodge. A two pass method is preferred to obtain good seed coverage. In
the first pass, 50 percent or less of the slurry is applied, followed by the second pass
that applies the remainder of the material. Each pass is applied in a different direction
(bidirectionally), which reduces the “shadow effect” created by just one pass and may
serve to better lock the matrix together (Bill Mast personal communication).
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Traffic Control – The contract must state how traffic safety will be ensured during
application. Will the contractor be required to supply signs, warning lights, or flaggers?
Keep Good Records
Hydroseeding is a complex task. Not only are several products being applied at different rates
at one time, but they must be evenly applied over large complex areas. A skilled hydroseeding
operator must be at the helm, and you must keep track of what is being applied and the acres
on which it is being applied. This will assure that you are getting the target amount and enable
accurate payment to the contractor.
The records begin with the original hydroseeding prescription. These are the planned application
rates of each hydroseeding material. It is not enough to know what you want as a finished
product on the site; you must understand how it will be accomplished. This means that you
must translate the prescribed product quantities per acre into how it will actually be applied.
These calculations can be challenging, especially when the hydroseeding operation is in full
swing. It is better to have some idea how this will work before you arrive in the field. Inset
10-21 is a guide through a process of determining how much of each hydroseeding material
must go into a slurry tank. These calculations, along with the contract specification, become
the operation plans.
Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat
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