Dormant seeding and frost seeding are two jobs that get talked about as one. Mix them up and you lose a season of seed. Dormant seeding is a real planting: you get seed into ground too cold to germinate, and it waits there until spring warms. Frost seeding is not a planting at all. You throw seed onto bare or closely grazed ground in late winter and bet the freeze and thaw will push it down. Dormant seeding is the one that suits native forbs, because a winter in the ground gives the cold, damp stratification those seeds need before they germinate. Frost seeding suits a legume like red clover going into existing sod. Neither one is a reliable way to put in warm-season native grasses, and neither one belongs on a slope. For a diverse native mix, the dormant pass is the better of the two.
Key Takeaways
- Wait on the soil, not the calendar. In the upper Midwest that is usually November, once the ground drops below 50 degrees and you are pushing for 40 or under.
- Frost seeding is a late-winter broadcast for legumes like red clover and annual lespedeza. It is not a way to put in a native grass stand.
- The reason to do a dormant pass at all is stratification. A cold, damp winter in the ground wakes forb seed up for you.
- A four-year NRCS study had dormant-seeded warm-season grasses fail in two of the four years, and spring was the most consistent of the three.
- Add about 25 percent to your pure live seed rate, and keep the seed no deeper than a quarter inch.
What is the difference between dormant seeding and frost seeding?
A dormant seeding is a planting. You put seed into soil too cold to germinate it and it sits there until the ground warms. A frost seeding is a surface pass. You throw seed onto bare or short ground in late winter and the freeze and thaw in the top inch opens and closes enough to swallow it.
| Dormant seeding | Frost seeding | |
|---|---|---|
| Timing | Late fall to early winter, after soil drops below 50 degrees | Late winter, roughly January through mid March |
| Method | Drilled or broadcast | Broadcast only |
| What gets seed into the soil | The drill, or a cultipacker behind a broadcast | Freeze and thaw cycles at the soil surface |
| Best suited to | Native forbs and diverse prairie mixes | Red clover, white clover, annual lespedeza into existing sod |
| Ground it suits | Level to gentle, with stubble or residue standing | Level, bare or closely grazed, with a real freeze and thaw pattern |
Frost seeding was a stopgap. That is the whole thing. The Tallgrass Prairie Center says it in its roadside manual: the practice grew up because people did not have a native grass drill to use. You throw seed out in late winter and you let the ground do the work a drill would do. That works for the right seed. It does not work for the rest.
When does the dormant seeding window actually open?
Read the soil, not the calendar. Kansas State puts it at below 50 degrees being workable and below 40 being what you want for a native mix. Iowa roadside crews start once the four-inch reading hits 50. Going early has a specific failure. A warm stretch germinates part of your seed, the first hard freeze kills those seedlings, and you find out in June that you are short. If the fall runs warm, wait it out.
There is a deadline nobody writes down, too. If you are drilling, you need ground you can still cut into. Once the top few inches freeze solid, the discs will not open it, and the window is closed whether the seed went in or not. In a cold fall the gap between too warm and frozen shut can close fast.
One thing from NRCS on grass seeding that is worth remembering: a dormant seeding goes in better on standing stubble than on bare tilled ground. Stubble holds the snow, holds the soil, and keeps the seed from blowing off in a January wind.
Which seed actually benefits from a dormant seeding?
Read your seed tag first, because the answer changes with what is in the bag.
Most native forbs carry a dormancy that only a cold, damp stretch breaks. Kansas State puts that at 30 to 60 days, and says a lot of forbs need both the cold and steady moisture before they will germinate at all. NRCS names this as the main reason to plant in fall. A dormant seeding lets the forb seed run through cold, moist stratification in your ground instead of in a fridge at home. Put in a pollinator mix with twenty or thirty forbs and the winter is doing the work you would otherwise do by hand in a cooler. That is the real reason for the practice. Nothing else comes close.
Warm-season grasses are another story, and this is the part people skip. The Bismarck Plant Materials Center ran a four-year study, spring against late summer against dormant, on big bluestem, Indiangrass, switchgrass, sideoats grama, and blue grama. Spring gave the densest stands and the most consistent ones of the three. Dormant trailed spring, and across the four years the dormant plantings failed outright two of the four times. Their own conclusion is that more work is needed before you recommend dormant seeding for warm-season grasses. The causes they list are all things you can watch on your own ground. Rodents eating the seed over winter. Wind moving it across bare ground in a snowless year. Seed germinating in an early warm spell and then catching a killing frost.
That is not a forever no. The same paper points to Nebraska work where a December dormant seeding of big bluestem and switchgrass gave acceptable stands, so it moves with latitude and snow cover. The plain version is simpler. If you have a spring to plant in, do not build a warm-season grass plan around the dormant window. Use the window for the forbs, and know what you are trading.
When does frost seeding work, and what is it really for?
Frost seeding is a legume practice. Most of the mess in this subject comes from people taking pasture advice and putting it on prairie seed.
Ohio State is blunt about it: frost seeding works with red clover, white clover, and annual lespedeza, and is not recommended for grasses or alfalfa. University of Minnesota puts seedling survival anywhere from zero to 60 percent, and does not hide why. You are not making a seedbed and you are not using a drill, so the odds are lower by design. Penn State says to go out early, while the ground is still frozen with a thaw coming by afternoon, and warns against mixing grass and legume seed in one pass. The denser legume seed throws farther, and you end up with stripes.
You will run into a contradiction if you search this yourself, and both sides are right. Missouri extension says the best conditions are frozen soil under a stable layer of snow. Tallgrass says do not frost seed ground that is iced or snow-covered. They are talking about two different jobs. Missouri is putting clover into established sod, where frozen ground is what lets you drive on it. Tallgrass is establishing natives on bare ground, where the point is soil loosened by freezing and thawing, and snow only keeps the seed off the dirt. Work out which job you are doing before you take either one’s advice.
Can you dormant seed or frost seed a slope?
Frost seeding, no. The Tallgrass manual does not recommend it on a slope, and the reason is plain once you picture it. Loose seed on a hillside through snowmelt and spring rain ends up at the bottom.
Dormant seeding is a maybe with conditions. The same guidance calls it a good option on level ground and more complicated on erodible slopes, since a cover crop seeded that late gives you no erosion protection until spring. If you have to seed erodible ground late, stabilize it with winter wheat. The frustrating part: slopes, ditch banks, and waterways are usually the ground people most want fixed. If that is your situation, drill it earlier in the fall with a cover going in alongside, or hold it for spring. There is a case for why no-till seeding holds that ground too.
How do you set a drill for a dormant seeding?
Depth. Shallow, then shallower still. The NRCS-based guidance says native seed should be covered with no more than a quarter inch of soil, and that some exposed seed is a good sign. NRCS gives a field check that needs no tape measure: if you cannot see a few seeds on the surface, you went too deep. The same publication calls planting too deep and poor weed control the two main reasons grass seedings fail. So take the aggression off. A dormant pass of native mix is a shallow setting, not a tillage setting. Walk behind it after the first pass and look at the ground. Everything else you do to the drill matters less than that.
Rate. Add about 25 percent to your drilled rate for a November or December seeding, which is what both the Tallgrass calendar and the Illinois DNR guidance call for. Work in pure live seed pounds, or that 25 percent is just a correction sitting on top of an error. The PLS math is in the guide to choosing a seed drill for small acreage.
One thing specific to this window: fluffy warm-season seed like big bluestem and Indiangrass bridges and packs in a hopper, and cold weather does not fix its manners. NRCS describes the fix as a dedicated fluffy seed box with picker wheels and agitators and oversized feeder tubes. If your machine does not have that, plan on stopping to check the box.
Where the Dew Drop Drill fits
If you have a flat field, a tractor, and a full-size drill you can borrow from the district in November, use that. It is cheaper, and it is the right call.
The case for a compact machine in this window is timing and access, and that is the whole of it. The window is short, the district drill is a phone call and a trailer away, and the ground that needs the work is often ground the big drill was never going to reach. A ditch bank. A fence line strip. A half-acre pollinator plot behind a gate. The Dew Drop Drill is three feet wide and runs behind a 450cc or bigger ATV or UTV, so it goes where the four-wheeler goes, and in November that is most places.
Two design choices matter more in November than in May. The metering is ground driven off the wheel, so your rate does not move with your speed, and on frozen ruts you speed up and slow down all the time without meaning to. The large seed box runs five picker wheels with five agitators, which is exactly the bridging problem above. Picker wheels and agitators are what NRCS names as the fix for fluffy seed, and they are in this box because the machine was built around native seed by people who could not buy one that would get onto their ground. It is $9,395 plus shipping, direct from the shop in Spencer. Three feet is still three feet, though. If you have forty open acres to put in this fall, this is not the machine for you.
FAQ
What soil temperature should I dormant seed at?
Below 50 degrees is workable, below 40 is better. Watch the four-inch soil reading, not the air. Air swings all day and soil does not. Any seed that germinates in November is seed you lose when the first freeze hits.
Can I dormant seed in the fall and frost seed the same ground in late winter?
Yes, and on a pasture it is a sensible plan. Drill the mix in November, then frost seed clover into the thin spots in late winter. Keep the species straight. Frost seeding holds for clovers and lespedeza and is not recommended for grasses, so do not expect a late-winter broadcast to save a grass stand that did not come up.
Is broadcasting seed on top of snow the same as frost seeding?
No. The Tallgrass Prairie Center makes the point directly. Sowing native seed onto snow is not really frost seeding, though it can work on fairly level ground. Frost seeding proper needs bare soil that freezing and thawing has loosened enough to take the seed. Throwing seed into windblown snow mostly just moves your seed to where the wind wants it.
Will a dormant seeding come up the first spring?
Some of it will. Staggered germination across more than one season is normal with native seed, not a sign something went wrong, and forbs in particular come up over several years. The Tallgrass Prairie Center’s establishment guide for landowners walks through what each year should look like. Plan on three growing seasons at minimum.
Working out your fall plan?
Call your conservation district first and ask what they rent and how booked November gets. If that does not cover the ground you actually need planted, send us a note with your acreage, what is in your mix, and what you would pull it with. We will tell you straight whether this machine fits.