It’s hard to describe the varied emotions involved in cleaning and mixing big piles of prairie seed. There is incredible optimism embedded in those tiny packages. After all, each seed has the potential to become a plant; maybe even the first of an entire colony of plants. On the other hand, most of them will fail to produce anything other than a little food for some animal or microbe.
Alex mixes up a big pile of seed with a grain scoop. Amber is helping too, but hidden behind a cloud of dust.
Yesterday was seed mixing day at our Platte River Prairies. We dumped bags and buckets of harvested seed into piles to be mixed and taken out to planting sites. In recent years, we’ve shifted our seed harvest focus; instead of aiming for the highest possible diversity of prairie species (150-200) to convert crop fields into prairie habitat, we’re now focusing on 30-40 wildflower species that are largely missing from some of our more degraded native prairies. Those degraded prairies had years of of chronic overgrazing and/or broadcast herbicide use before we obtained them, and haven’t really increased much in plant diversity, despite over 20 years of the best management we could give them. By increasing the number of plant species in those prairies via overseeding, we hope to increase the quality of pollinator and wildlife habitat, as well as the overall ecological resilience of the prairie community.
We process many of our seeds by running them through a heavy steel fan blade that used to be part of a riding lawn mower. It’s a quick and effective way of breaking seeds out of pods and off of stems.
To be clear, when I say “we”, I’m mostly talking about the Platte River Prairies staff and volunteers who are actually doing the work these days. For many happy years harvesting seed, but that torch has now been largely passed to others. I still harvest a modest amount of seed on my own time, mostly during evenings and weekends, for use at our family prairie, but I’m just an advisor for the bulk of the restoration work going on at the Platte River Prairies. Regardless, it was immensely gratifying to help out yesterday. It felt great to run those seeds through my fingers and inhale a little seed dust into my lungs (though we wear masks to minimize the dust inhalation).
Alex dumps a bag of seed onto the pile.
While I like thinking about each seed as a potential plant, I also recognize how few of them will actually make it that far. Even in cropfield restoration work, when we’re broadcasting seeds onto bare soil with no preestablished competition from other plants, only a small percentage of seeds really end up as plants. Some are eaten by animals before they get a chance to germinate. Others don’t land in a place where they get the light and moisture they need. Still others germinate, but are then outcompeted by neighboring plants, eaten by something, or don’t get rain at the right time to sustain them.
When we’re overseeding an existing prairie, the number of planted seeds that turn into plants is far lower still. We burn ahead of time to create bare soil, and graze to reduce competition, but there are still very few spots where a seed can land and have a good chance to thrive. That means that the vast majority of those wonderful little seeds of promise just die. Though, as we discussed yesterday while we worked, even the ones that die are feeding something – birds, mammals, insects, fungi, etc. – so it’s not that they’re really wasted. It’s just that we didn’t really spend all that time harvesting seeds just to feed fungi.
Instead of focusing on how many of those seeds will become fungus fodder, though, I’d prefer to think about the good that will come from those that survive. By harvesting and broadcasting those seeds, we’re transforming prairies with very few summer wildflowers into prairies with enough floristic diversity that they will support a more robust pollinator population and provide better habitat structure to a number of wildlife species. Even if one tenth of one percent of the seeds we plant germinate, we’ll be making a big difference.
This overseeded prairie is not yet where we’d like it to be in terms of plant diversity, but it’s far better off than before it had even the number of flowers shown here. Hopefully, now that some of these wildflowers are established, they’ll be able to spread on their own as we provide helpful management.
Soon, we’ll be releasing those seeds into the wild to take their chances in the world. Most of our planting these days is done by machine, which helps us cover a lot of ground quickly, with fairly even distribution of seeds. That’s all well and good, but I sure get a lot of joy from hand-tossing seeds at our family prairie. Not only can I aim the seeds for areas I think (though I’m totally guessing) they might survive best, I can also give them a little good luck wish as they leave my hand. Later in the season, when I return to look for seedlings, I can congratulate both the seed and myself on our success whenever I find a new plant. With enough of those successes, we’ll slowly rebuild the diversity and resilience that will carry these prairies well into the future.
Alex, Amber, and a big ol’ pile of potential prairie plants.
The Prairie Ecologist 
Chris, I have been enjoying your Prairie Ecologist newsletter ever since I discovered it on a trip to photograph sandhill cranes with Michael Forsberg a year ago.
I am moving to a 2.8-acre lot on a bluff near the Missouri River in SD and would like to return much of the plot back to prairie. Can you help with any resources I might consult in my effort? Any info would be much appreciated. I have not found an organization like yours in southeastern SD.
Thank you.
Tim Schreiner
Sent from my iPad
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Hi Tim,
I would start by contacting Prairie Plains Resource Institute (prairieplains.org, ppri@hamilton.net, or 402-694-5535) They do restoration work throughout eastern Nebraska and would know best what kinds of resources might be available to you up in your new neck of the woods. If you don’t have any luck, feel free to email me at chelzer@tnc.org and I can do some more poking around.
Hi Tim (and Chris!),
I work with NRCS in Nebraska and South Dakota and would also be happy to help you! Native seed in South Dakota can be a little tricky to source. Feel free to reach out to me at raeann.powers@xerces.org if you need some additional guidance.
Chris,
Do you think some of the successes/failures of seeds to grow could have something to do with different stratification needs? How do you take this into account when selecting plants for restoration/introduction?
Thanks.
Hi Mike, yes, each species has its own requirements for stratification prior to germination. Usually, we plant cropland to prairie during the winter, and that seems to take care of what most species need to germinate. With our overseeding, we often wait until we can get a burn done, and while burning in the fall would be ideal, it’s often early to late spring by the time it happens. So far, we’ve had pretty good luck seeding after those spring burns, so for the species we’re using, we must not be overly limited by stratification requirements. Of course, it would be great to do a comparison of fall vs. spring planting on the same site to test that, but aside from the logistical issues, there SOOO many other complications that make comparisons difficult, including the fact that planting earlier gives animals more time to find and eat the seeds before they germinate! Great question though.
So what would you say are your top ten “must haves” plants for your degraded sites?
Great question. We prioritize species that add to the structure of habitat, flower abundantly in the summer (when we’re otherwise short of pollinator plants in those sites), and that we know from experience establish well from broadcast seed. So, some of our top plants include Maximilian sunflower, stiff sunflower, sawtooth sunflower, rosinweed, prairie clovers, wild bergamot, Canada milkvetch, and black-eyed Susan. As we’re going through the season, though, we look for big flushes of flowers that would be easy to harvest and grab some of those too. It’s a combination of planning and opportunism…
Follow-up question. For some of the longer lived species, do you try adding any innoculum of “good fungi” (as opposed to the bad fungi that you malign as seed killers)?
We’ve never had to innoculate our soils. I’m pretty leery of the marketing on various innoculants anyway – since we know very little about what we have or should have in our soil communities, I’m not sure why I’d take the risk of bringing in something that would be counterproductive. Even in our crop fields, we’ve not seen evidence of species not establishing well because of missing soil components like that.
Kudos to these seed producers and their efforts…I have some small understanding of how physically hard this work is, but also how sound the sleep is at night knowing you are doing your best to improve the world in ways few understand. I do, and stand in frank admiration of you all.
Do you sow a sample of your seed into a greenhouse flat to determine the germination rate for the various species? I wonder if some of the species might not do well with your processing and handling setup.
Not any more. We did quite a bit of seed testing 10-15 years ago, but only of the more common species in our mixes. Again, we’ve not had many failures. Just about every species we’ve ever harvested is not growing in our restorations. Those few that aren’t (I don’t even know where that list is anymore) are mostly species for which seed is limiting, along with a couple sedges that no one (that I know of) has had luck germinating – Carex heliphilis and C. eleocharis, for example.
At seed processing days locally, legumes are scarified by getting rubbed between blocks of sand paper. Unfortunately, the result of this is often the seeds are scarified to the point that they get turned into flour. Since you did testing years ago this situation does not sound like the issue.
I would suggest sowing a sample of your seed into prairie soil from the site in a greenhouse so you can evaluate the germination and early growth. This would be a simply way to eliminate problems with the soil.
I’m surprised people are having trouble with the sedges. I have grown a handful of the most conservative prairie sedges from Illinois without any issue. I just direct sow them in flats I keep outside and after a few years I have a nice turf that I can divide, put into plugs, and plant after the roots have established. Although, I am finding that Carex tetanica has a low survival rate after I plant it out in the field. It only succeeds for me occasionally in the best situations. Some plants are best established by taking divisions and moving them to the location you want them to grow instead of putting the effort into getting them established from seed.
Very interesting. I did not know what goes in to managing such a property that you have been managing. Fascinating and of course makes sense!!
thanks
Hi Chris
Why don’t you guys just hand plant the seeds that you want to grow? Wouldn’t that give them a higher rate of success as well as decrease cost due to lost seeds and hours of labor?
Suzanne
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It’s a fair question, Suzanne. It basically comes down to an issue of scale. Yes, it would be more efficient, in terms of number of seeds wasted, to plant individual seeds where we think they’d grow best, but it would take a very long time to do that, especially when we’re trying to overseed 150 acres or so per year. On the other hand, seed is cheap for us (we harvest much of it by machine, or by hand from large patches), so we can afford to “waste” some seeds in return for being able to treat more acres each year. The other aspect that’s important is that even if we hand planted seeds in favorable-looking areas, many of them would fail – either because of random events or because we stink at predicting successful sites (or both, more likely). In that case, we’ve invested a great deal of time in each seed and still have a low success rate. At least when we’re broadcasting lots of seeds, we can feel confident that many will land in places where they can grow well, even if many more don’t. We’ve also used seedling plugs in the past, and they can also work. In that case, however, we’re investing even more effort up front in growing plants in the greenhouse and then transplanting and watering them. A few thousand seedlings takes an amazing amount of work, and a fairly high percentage of them will still fail in the early days after planting them out. If we had a good greenhouse (ours blew down in a storm years ago) and a strong cadre of volunteers, seedling plugs might make sense as part of our strategy, but for now, it doesn’t fit our available infrastructure and labor supply. Anyway, lots of ways to attack this – we’ve chosen the one that seems to fit our particular situation best. Good question!
Thanks for the detailed and interesting reply Chris.
Here is something else that is worth trialing. The book “Garden Revolution: How Our Landscapes Can Be a Source of Environmental Change” suggests applying sulfur to acidify overly fertile soils. Acidified soil has lower nutrient availability. The author suggests doing this when converting turf grass into natural meadow vegetation (an eastern prairie) or to establish acid loving sedges. Your prairie grasses seem to be a lot like turf and this technique might be useful for getting forbs established.
Seeding in general is better than plugs I think as a seedling developed in situ has a better chance of developing a natural, deep taproot. Grassland forbs planted from pots in one trial here (Australia) apparently were found to have appallingly shallow and underdeveloped roots systems. Have you tried a seed drill with any of them? Obviously you would need to have access to the machinery, and have seed that is sowable (not covered in long awns/pappus/etc).