Erosion Control and Broadcast Sowing

I Have this Bank Behind My House:

In fall and winter we receive many calls beginning with this sentence, concerned with this complicated topic. Frequently, a customer has been involved in construction in the summer, which has impacted a slope, roadcut, or other vulnerable area. In the fall or winter, they call us for seeds. Advance planning is desirable.

We are happy to consult with you on these topics, but phone calls  longer than 15 minutes duration will require scheduling and a nominal fee. If the project is complicated enough that more time is required, you may need the services of a professional engineer. In either case, reading this information piece will help our conversation be useful to you:

Seed Broadcasting refers to the act of flinging seeds upon hopefully weed-free ground to produce a continuous biomass of plants, (a meadow, field, grassland, prairie, clearing), as opposed to seeding into containers or flats for later transplanting of individual plants into the ground. It can be done by hand, with a seedspreader, or for large acreage, with a hydroseeding machine. Specialized companies own and operate these machines.

Though an ancient activity, this is for many of our customers a new aspect of native plant horticulture. For those of you who are new to large-scale broadcast sowing of native seeds, here are some helpful concepts and principles Remember, every situation is different, and prescribing over the phone has its limitations.

Types of Erosion:

To greatly simplify, there are three main kinds of erosion:

1. Soil splash erosion, caused by the impact of raindrops directly hitting the soil, is ameliorated by the presence of vegetation. This is the simplest kind of erosion to address.

2.Deep Erosion on disturbed land, in areas that for one reason or another have lost the plant roots that form a strengthening network of fine plant hairs and larger roots to tie the soil together, is what concerns most homeowners. Many new products, like fiber rolls, erosion-control blankets,  willow walls, and different forms of jute netting, use natural materials to control erosion and hold the seeds in place till they grow roots to hold the soil and foliage to protect it.

3. Natural Erosion, part and parcel of the geology and topography of the area, includes slumps and landslides. Our coastline is naturally full of this kind of erosion, which can only be stopped or delayed by large engineering projects. Though we supply seeds for such projects, we do not design them.

FAQS about Broadcast Seed Sowing:

1. A deeply engrained idea continually surfaces in our conversations with customers – that wildflower seeds or native grass seeds can be broadcast in the fall and will automatically and immediately eliminate erosion that same fall and winter.  

2. Seeds themselves do not help with erosion problems. It is the mature plants with mature rootsystems that bind the soil together and that can, in certain situations, slow, decrease, or resist erosion. Timing of rain may or not be perfect for creating mature plants. If not, irrigation is necessary.

3. All seeds require moisture for germination. Rain or irrigation is required to start the plants growing and keep them growing. The rains that will naturally begin and foster germination usually arrive AT THE SAME TIME as the need for erosion control.  Ways to get around this timing situation will depend on the nature and severity of the problem.One such strategy is to begin seed sowing in the summer, using artificial irrigation, so that plants will germinate and start growing before the fall and winter rains.

5.The steeper the slope and the larger the area, the more likely you are to need professional engineering help. Please seek help from engineers or restoration ecologists.