Rolling out the new seed mixes
By: Ken Graeve, Erosion and Stormwater Management Unit Supervisor, Office of Environmental Stewardship
Back in 2024 MnDOT introduced new standard seed mixes. These went into effect starting with the September 2024 lettings and since then are expected to be used on all projects utilizing MnDOT specifications. Here's a quick update on those new seed mixes and available resources.
Faster establishment
One of the goals of the new seed mixes was to get faster perennial vegetation establishment. Below are photos from a couple of projects showing that that there is more rapid establishment with the new mixes. The faster establishment of perennial vegetation is a result of replacing the annual cover crops with perennial cool season grasses.
Figure 1: A dense cover of seedlings has emerged after about one month of growth.
Figure 2: Two months after planting with one of the new seed mixes, this roadside is well on its way to having enough vegetation to close out the construction stormwater permit.
Which Seeding Manual?
As a reminder, there are two versions of the MnDOT Seeding Manual posted on the Erosion Control website. At this point the old version is only intended for construction use, because any current design work should be using the new seed mixes. Please remember to use the 2023 edition only for projects that are using the old set of seed mixes, which is projects that let before September 2024. Use the 2024 edition for projects using the new seed mixes, which should be all projects let on or after September 2024.
Which specifications?
The contract requirements for the new seed mixes can be confusing. Some of them have been moved to the 2025 Standard Specifications for Construction (2025 Spec Book) but some still reside in the 2025 Boilerplate Special Provisions (Boilerplate). To make this easier to navigate we have assembled a 2025 Guide to Erosion and Stormwater Specifications and Provisions (Word). This shows standard specifications and any changes made via special provision together in a single place, in sequence so they're easy to follow.
Questions?
Please contact Ken Graeve at kenneth.graeve@state.mn.us, or anyone in the Erosion and Stormwater Management Unit if you need more information.