|‘TIS THE SEASON FOR DORMANT SEEDING
Now is the time for dormant seeding your native grasses and wildflowers. At least for most people. If you live in the southern US it may be too early yet. It is important to wait until the soil temperature has cooled to less than 55 degrees Fahrenheit to prevent any germination and subsequent winter kill. However, I make this important exception; if any forbs germinate with a soil temperature of 55 or less, it is OK. There are a number of forbs that will germinate and form a rosette over the winter, especially in warmer climates.
There are many people who prefer dormant seeding over spring seeding. Most, who prefer dormant seeding, are doing high quality restorations with a large diversity of forbs or more simple plantings with a large forb component. My general experience has been dormant seedings tend to have more weed problems the first couple of years but with diligent management can be very successful. There is no doubt, dormant seeding perennial wildflowers is the best approach.
If you are planning a dormant season seeding this year I hope you have already done some preparation. If not, it may be too late this year, except for no-till into crop fallow or plow down. Preparation is similar as for spring planting. If planting into an existing sod, the sod will have to be either plowed down and a seed bed prepared or sprayed with herbicides to kill the sod. Herbicides are much slower acting in cooler temperatures. It may take several weeks before the effects are noticeable. In no-till situations into sod I always recommend removing the residual litter somehow, by grazing, haying or burning prior to spraying or burning after killing the sod. Burning is usually not necessary if the sod has been aggressively grazed or hayed. The ultimate goal is to remove as much litter and thatch as possible before no-tilling. As with spring seeding, planting depth is critical. It is particularly important that seeds are no deeper than one quarter inch. The freezing and thawing of winter weather could work the seed too deep. Conventional wisdom also recommends increasing your planting rate by 25% to compensate for lost seed caused by over wintering. My personal feeling is that most seeding rates are too high to begin with. Therefore I don’t increase the rate. However, I begin with what I feel is a more appropriate rate.
The following, in regard to dormant seeding, is submitted by Paul Knox and used by his permission.
My farm is in SE Iowa on HEL (Highly Erodible Land), most of which is in CRP, so in all cases its brome sod that I'm working with. I mow in July, close as possible and then kill the regrowth with Roundup in early September. I generally seed by hand broadcaster in early January, making sure that there is no snow when I plant. I did plant one field with a Truax drill in late November. In all cases the stands turned out terrific, of course the drilled stands are more uniform.
I can't understand why people insist on planting dormant seed in May or messing around with soaking it to try and stratify it, instead of working with Mother Nature and planting it when and how it was intended.
Herbicide is the key to getting a stand in one or two years instead of 3-4. I've found that 2 qts of Atrazine, Princep (simazine) or Bladex (cyanazine) will control weeds to allow for a real good stand the first year.
Most of my problems are with perennial broadleaf's, which could probably be controlled with 2-4D also, however foxtail tends to invade overnight if a residual isn't used.
I have also broadcast mixed native grasses & wildflower mixes in January and used mowing alone (other then Roundup to kill sod) and have a beautiful stand 3 years later. In no cases have I tilled the ground.
* Editors note: Check with your local authorities on the legality of using any herbicide for native grass/wildflower plantings. It is also important to point out that the use of the herbicides mentioned above were in grass only plantings. No forbs were included. 2-4D will kill forbs.
Research done at the USDA, NRCS Plant Materials Center at Bismarck, ND does not recommend dormant seeding of certain cultivars of native grasses in the Northern Great Plains. Bison big bluestem, Tomahawk indiangrass, Dacotah switchgrass and Killdeer sideoats grama (all ND origin) were tested. Each were planted in study plots on November 18, 1990 and October 30, 1992 and May 5, 1993. Data collected from the dormant plantings showed Dacotah switchgrass had the greatest plant density. Poor stands and low counts were recorded for the other three species. It was also noted that following initial spring germination, spring frosts injured young seedlings but Dacotah switchgrass exhibited more tolerance to the spring frosts than the other species. From: Dormant Seeding of Selected Native Warm Season Grasses. Dwight A. Tober, Russell J. Haas, Michael J. Knudson, USDA SCS, Plants Materials Center, P.O. Box 1458 Bismarck, ND 58502.
So, do you dormant seed or not? I’ve always maintained that if you talk to 10 "experts" on native grass/wildflower establishment, you will get 10 techniques. It’s not that any of them are wrong, those are just the techniques those individuals have had success with. My personal preference is spring seeding because I get more consistent results. I believe dormant seeding is appropriate in certain circumstances, 1.) If your planting is a pure wildflower planting with lots of perennials, 2.) If your planting contains a high proportion of wildflowers, 3.) Your spring schedule prevents you from doing a spring planting, 4.) You have too many acres to complete in the spring planting season, 5.) If borrowing or renting equipment, it is more available during the dormant season. Though I prefer spring seeding, bottom line is, there is no reason not to dormant seed.