Seeding

Seeding thompsbb Thu, 01/18/2024 - 11:19

There is no single, correct way to seed native vegetation and there is no substitute for experience. Successful planting is the result of getting familiar with the equipment and developing the “art” – one’s own way of working with natives. As a wise man once said: “It won’t grow in the bag.” The message:

Don’t worry so much about how to plant it. Get out there and start seeding.

Basic steps to successful seeding:

Use good seed.
Place seed in direct contact with the soil.
Don’t bury seed more than ¼ in. deep.
Pack seed tightly to the soil.
Include erosion control measures where necessary.
Mow weeds during the first growing season.
Conduct prescribed burns every three to five years.

Timing

Timing thompsbb Tue, 03/19/2024 - 09:09

May and June are ideal seeding months, but road construction projects are rarely ready for seeding at this time. The following seeding calendar provides suggestions for protecting slopes and improving seeding success throughout the year.

January to mid-March

Winter months occasionally present windows of opportunity for frost seeding, a practice that originated as a way of incorporating seed into the soil when a native grass drill was not available. Seed is spread over bare soil made friable (loose or porous) by a cycle of freezing and thawing. Results can be good, but opportunities can be brief.

Be ready to jump on it.
Include oats as a cool-season nurse crop.
Do not frost seed on areas covered with ice or snow.
- Occasionally native seed is sown on top of snow. Technically this is not frost seeding, but can be an effective seeding method on relatively level sites.

Frost seeding on slopes is not recommended.

Late March through April

If site conditions permit (ground not frozen or too sloppy) this can be a good time for seeding. Warm-season grasses won’t germinate until soil temperatures reach 60 degrees Fahrenheit. Include oats as a cool-season nurse crop.

May and June

This time of year provides the best soil temperature and moisture conditions for germination and survival of warm-season species, including most prairie grasses and wildflowers.

July and August

Although every county can point to successful plantings during these months, hot, dry summer conditions are generally less favorable for planting natives. Consider a temporary seeding at this time, with the permanent, native seeding in the fall or the following spring.

If natives must be seeded now:

Drill, rather than hydroseed, for maximum seed to soil contact.
Increase seeding rate 25%.

Include appropriate nurse crop.
Mulch with straw, and crimp or tack straw into place.

September and October

Native seed germinating this late in the season is unlikely to develop enough root reserves to overwinter. Yet some of these plantings do succeed, maybe because a lot of the seed does not germinate until spring. Research is needed.

Erodible sites must be stabilized with winter wheat.
Increase seeding rate 25%.

November and December

Dormant seeding, considered a good option on level ground, is more complicated on erodible slopes. Cover crops seeded this late won’t provide erosion control until spring. The majority of native seed will remain dormant over winter. While some forb species do better when dormant seeded, some of the native grass seed planted at this time will deteriorate over winter.

Erodible sites must be stabilized with winter wheat.
Increase seeding rate 25%.

Roadside Manager Insights

Timing is everything, watch the weather and don’t just seed a site to get it off the list.

-Joe Kooiker, Story County, 2024

Ideally, we begin dormant seeding in October or November once the 4” soil temperature reaches 50 degrees, but if erosion is a concern or there is an issue regarding a regulatory permit, we will seed earlier and may increase the seed rate some and hope for dormant seed.

-Jim Uthe, James Devig, Dallas County, 2024

I try not to seed in August, September, or early October. I prefer to wait until November, then drill into a cover crop and mow the following spring. If weather conditions deteriorate in November, I can still seed in the spring. However, there are many factors that can influence when seeding gets done including size of project, time available, topography, etc. Small sites and those that are not conducive to drilling typically get seeded as soon as possible.

-Wes Gibbs, Jones County, 2024

I don’t intentionally wait to frost seed. I might consider it, but only on flat areas in perfect conditions.

-Wes Gibbs, Jones County, 2024

Site Preparation

Site Preparation thompsbb Tue, 03/19/2024 - 09:23

Site preparation enhances seed to soil contact, helps ensure proper planting depth and can even provide erosion control.

Prior to working the site

‌Walk the site looking for gullies, culverts and other hazards (e.g., logs, stones, stumps, etc.).
If weed growth is excessive, mow and disk stubble into the soil, if possible.
Check with utility companies before disking.

Calculate the size of the area to be planted and the amount of seed it will take.
Size up the watershed and the site’s erosion potential.

Seedbed preparation for drill seeding

Ideal seedbeds are friable, firm and smooth

To reduce erosion, don’t smooth up the site until just before planting.
Relatively level sites can be worked with a disk, chain-tooth harrow or similar equipment.

‌To avoid excessive clodding, don’t work the site while it’s too wet.
Cultipacking can help firm the seedbed and reduce clods.

Seedbed preparation for hydroseeding

Seedbeds can be left rougher to reduce erosion.

Steep slopes can be ripped with a wide-track dozer.
Directional tracking can be used to interrupt water flow.

Work the site perpendicular to the slope to interrupt water flow.

Heavily compacted soils

Try to work the site to a depth of three inches.
A heavy disk might be necessary.

‌Some sites may need to be worked with long bulldozer tines.

An illustrated bulldozer creating grooves in a sloped roadside. — This diagram illustrates directional tracking: dozer treads create grooves perpendicular to the slope.

Getting your seeds to grow is a priority, try to get good seed to soil contact when possible.

-Joe Kooiker, Story County, 2024

For hydroseeding we prefer the site to be rough and a little soft. We seed immediately after the construction equipment has left, with no additional seedbed preparation. The rough texture keeps the seed in place and the softness allows for better root penetration. However, for drill seeding, firmness is the most important factor. It is easy for seed to get buried too deep in soft seedbeds, either during or post planting.

-Doug Sheeley, Dallas County, 2024

Cover Crops

Cover Crops thompsbb Tue, 03/19/2024 - 10:13

There are two kinds of cover crops. Cover crops planted along with the permanent seed mix are called nurse crops or companion crops. Those planted by themselves pending a better time to plant the permanent mix are referred to as temporary seedings or stabilizer crops.

Cover crops help hold the soil and are recommended on slopes 3:1 or greater. Oats Avena sativa, annual rye Lolium multiflorum* and winter wheat Triticum aestivum are excellent cover crops because they are inexpensive, easily established and not overly competitive.

Recommended nurse crops/companion crops (planted with the native seed) — per acre

‌Spring

1.5 bushels oats or
1 bushel oats and 5 lb. annual rye

‌Summer

2 bushels oats or
1 bushel oats and 10 lb. annual rye

‌Fall

30 lb. winter wheat

Recommended Temporary Seedings/Stabilizer Crops (native seed to follow in the spring) — per acre

Summer

1 bushel oats plus 10 lb. annual rye and one of the following warm-season species:

5 lb. piper sudangrass
10 lb. millet (Japanese or Pear varieties)
30 lb. sorghum (grain or forage)

‌Fall

20 lb. annual rye or
60 lb. winter wheat

Caution: For native plantings, winter wheat is preferred over winter rye. Winter rye is taller, more persistent and possibly allelopathic, chemically inhibiting the growth of wildflowers. There are many kinds of rye: annual rye (Lolium multiflorum); perennial rye (Lolium perenne) and winter rye, cereal rye and grain rye (all names for the same plant, Secale cereale). Do not seed piper sudangrass, millet or sorghum too heavily. One good rain can cause mass germination. Piper sudangrass may cause concern among landowners as it is sometimes confused with shatter cane.

Cover crop conversion chart

Species	Pounds in a bushel	Seeds in an ounce	Seeding at 1 bushel/A results in
Oats	32	910	10 seeds per square foot
Winter wheat	60	937	20 seeds per square foot
Annual rye	-	12,710	Seeding at 10 lb./A results in 46 seeds per square foot

Cover crops are as much for public perception as they are for erosion control. Having your plantings turn green in a timely fashion is essential for a program’s success.

-Joe Kooiker, Story County, 2024

We use a bushel per acre of winter wheat as a nurse crop when dormant seeding with a hydroseeder. In the spring when hydroseeding, we use a bushel of oats if the soil prep, soil moisture forecast are appropriate. We may continue to use oats through summer in good soil that’s adequately prepped and if moisture is in the forecast. We will blend in annual rye and/or even pearl millet or may substitute the oats for these species as soil conditions and forecast become less favorable.

-Jim Uthe, James Devig, Dallas County, 2024

In addition to increasing our native seed rate on very steep slopes, we also increase our cover crop rate, we essentially do this by applying more material out of the hydroseeder as concern for erosion increases.

-Jim Uthe, James Devig, Dallas County, 2024

In typical Iowa soils, fertilizer and plant growth hormones aren’t needed. However, we’ve used various growth stimulants along with starter fertilizers and various other amendments on steep slopes with poor soil, and have had very good results. It’s cheaper to quickly establish a cover crop than to spend the time and resources repairing or redoing a project. It’s also good PR with the engineering staff and public to see a quick green-up. Again, we only use this practice on areas of very poor soil with a lot of erosion potential, or to protect a high-dollar project.

-Jim Uthe, James Devig, Dallas County, 2024

The majority of our regraded slopes are steep. I regularly use 2.5 bushels of oats, 6 lbs. of annual rye and 3 lbs. of timothy along with the permanent seed mix. This provides a better chance of stabilizing the slopes while the permanent seeding establishes, and I haven’t noticed any detrimental effect to the planting’s long-term success.

-Linn Reece, Hardin County, 2011

The nurse crop can be added to the slurry in the second pass with good success. Wheat and oats are very difficult to keep in suspension in pure water, so it’s better to include in the mulch in the second pass.

-Wes Gibbs, Jones County, 2024

On large, contracted projects we fertilize the cover crop to DOT specs; the flush of weeds has usually subsided by the time we plant natives in the fall or following spring. We do not use fertilizer when hydroseeding.

-Wes Gibbs, Jones County, 2024

When broadcasting in light tillage we use some, but sparingly. I wouldn't recommend fertilizer with natives, but it does help cover crops planted in nutrient-deficient soils.

-Wes Gibbs, Jones County, 2024

I have used several different cover crops from oats, winter rye, buckwheat, perennial rye, and going to experiment with sorghum grain and Sudan grass, and mellites for summer ditch cleanouts and other projects. I will utilize these species because they are drought tolerant, and they are fast growing. These are things that we are all battling with in the ROW’s. For rates of current use – oats 30 to 40lbs/ac, winter rye 1bu/ac, perennial rye 10lbs/ac I keep this thin with the rye and oats to get some fast green on projects but then the natives can out compete them in the long run, and buckwheat 10 to 20lbs/ac on summer projects keep it on the lighter side with oats and perennial rye because they have a large leaf and can cause shade out of natives until a mowing on a first year seeding. I like buckwheat in my summer blend because it is fast growing and drought tolerant.

Most of these cover crops are broadcast seeded, however I have done some drilling and mixed it in with the hydroseeder as a method of seeding. I have seed success with all application methods.

-Griffin Cabalka, Black Hawk County, 2024

Mixing Seed

Mixing Seed thompsbb Tue, 03/19/2024 - 10:58

Native seed can be ordered pre-mixed. If species come individually bagged, they will have to be mixed thoroughly. Mechanical seed mixers are available. Otherwise hand mix as follows:

‌On a calm, dry day seed can be mixed outdoors on a smooth, concrete surface. Otherwise select a well-ventilated building with a hard, smooth floor.
Wear a dust mask and safety glasses.
Prop the door open wide and turn on the exhaust fan.

Measure out the seed with a scale and dump it in piles.
Mix seed with scoop shovels.
After mixing, put seed in trash cans for hauling to the site.
Seed that won’t be planted right away must be kept cool and dry.

Seeding Methods

Seeding Methods thompsbb Tue, 03/19/2024 - 11:06

There are three seeding methods: drill seeding, broadcasting and hydroseeding. Each has advantages and disadvantages.

Drill seeding

Seeding with a native grass drill is the preferred method on level rights-of-way. Drilling is a one-step process and is quicker and cheaper than hydroseeding. Drills do a better job establishing native grasses and produce faster results overall.

Drills do not work well on slopes. At 3:1 or steeper, the drill will try to slide sideways causing the disk openers to dig in and bury the seed. Projects with silt fences present another challenge; maneuvering a tractor and drill around these fences is difficult.

Drill seeding tips

Calibrate the drill in the shop and set the rate a little lighter than what you actually want.
Bouncing over the ground, a drill set at 6.5 lb. to the acre might actually seed 8 lbs. to the acre.
When planting very clean seed with an older drill, use a filler to slow it down. Bulk-harvested seed or fluffy little bluestem works well.
For good seed distribution, use the small seed box for fine seed and the fluffy seed box for grasses, large forb seed and seed that hasn’t been well-cleaned. Alternatively, sprinkle a portion of the forb seed on top of the other seed in the drill’s middle hopper, then add more forbs every other round or two.
Do not plant native seed deeper than ¼ in. Most native seed is small and lacks the energy to emerge if planted too deep.

The trash plow attachment on a native grass drill should just scratch the surface. If it’s making furrows, it’s planting too deep.
For uniform coverage, drill seed at a light rate and go over the area twice.
Multiple passes packs the seed well and creates more rills that hold seed and interrupt water flow.
To prevent seed from being buried too deep, disconnect the lower end of the drill’s seed tubes. Some of the seed will land on the soil surface and not be buried in the furrow. Some people prefer to unhook only every other tube. Others unhook only the tubes coming from the small seed box.

Hydroseeding

Hydroseeding is ideal for bridge approaches, cleanouts, culverts and wet or steep slopes. In most cases, the entire project can be hydroseeded from the shoulder. Other hydroseeding advantages — hydromulch reduces soil erosion; the risk of seeding too deep is eliminated; colored mulch on the soil makes a positive impression on the public.

Filling the hydroseeder takes time, so drilling or broadcasting are usually quicker for larger projects. Other hydroseeding disadvantages — mulch is expensive and can double the cost of a seeding, the seeding rate is harder to control, and hydroseeding is strictly a bare-ground application.

Hydroseeding tips

It’s best to seed after a rain, not just before. Seed and mulch stick better on moist soils. Some moisture is captured under the mulch. Mulch needs time to set up before it rains.
Increase overall seeding rate by 25% to compensate for seed damaged going through hydroseeder mechanics and for seed that gets hung up in the mulch.
The “shadow areas” behind larger dirt clods sometimes get no seed. For better coverage, try to seed in two passes, one from each direction. Seed lightly — so the seeding rate is not doubled — at 7 to 8 mph, with flow rate reduced.
An 800-gallon hydroseeder is the minimum recommended size. A 1,500-gallon hydroseeder can cover 1/3 acre per load. With a machine of this size, seven 50-lb. bales, or 350 lb. of mulch per load, yields about 1,000 lb./acre.

Seed the area farthest from the road first.
On steep slopes, try to embed the seed by using a more concentrated stream and holding the gun at a sharper angle.
For the sake of efficiency, most county roadside managers apply seed and mulch in one pass. The “two-pass method” — seed applied first, hydromulch to follow — results in better establishment since more seed is in direct contact with the soil.

Hydromulching rates

1,000 lb./acre — a token amount to help carry the seed and show what area has been seeded
2,000 lb./acre — appropriate for most 3:1 slopes

3,000 lb./acre — very heavy rate for long, steep slopes

Broadcast seeding

Broadcast seeding is a viable option now that commercially available native seed is cleaner and less fluffy than it once was. When applied with broadcast seeding equipment, this debearded seed flows better and slings farther and truer than in the past.

Broadcast seeding tips

Broadcasting finer-seeded species prevents them from getting buried under too much soil.
For very clean seed, the Vicon broadcaster can be adjusted down to the “nth” degree.
For fluffy seed just open the gate a lot wider.

A broadcast seeder on a 3-point is more compact than a drill and easier to get in and out of ditches.
Broadcasters can be backed up to silt fences to sling seed on both sides.

Hand seeding

Scattering seed by hand followed by light raking is very effective for smaller sites and prevents fine seed from being planted too deeply.

To improve distribution, mix the seed with some kind of carrier. Sand is best. Kitty litter or oats are also used.
Mix the seed and carrier in a bucket and scatter it over the site by hand.

Many wet prairie species have fine seed and should be seeded this way.

Packing the seed

Packing seed tightly to the soil ensures a more consistent flow of moisture from the soil to the seed. The result is better germination and better seedling survival.

Packing is most important after broadcast seeding, but is always beneficial.
A 4-ft. cultipacker section on a 3-point is very effective and will go places the tractor and drill can’t.

Roadside Manager Insights

We lightly disk the seedbed before hydroseeding, if possible; cultipack after we seed; then apply mulch (two-pass method).

-Joe Kooiker, Story County, 2024

The hydroseeding is a great method of seeding, but not always necessarily the tool for the job.

-Joe Kooiker, Story County, 2024

When filling a hydroseeder from a creek, know your source. Don’t fill from an area with invasives (e.g., purple loosestrife).

-Jim Uthe, James Devig, Dallas County, 2024

Filling near the site with a trash pump has drastically improved the efficiency of the process. We mounted the pump on the seeder, so we simply drop a fill line into the water and turn on the pump.

-Josh Brandt, Cerro Gordo County, 2010

When hydroseeding, be sure to mix seed thoroughly in the water, both initially and periodically during application. Our Finn hydroseeder can reverse the mechanical agitation, which is helpful.

-Jim Uthe, James Devig, Dallas County, 2024

We have better germination with lighter hydromulch rates (400–500 lbs./acre).

-Dave Sedivec, Chickasaw County, 2010

There’s been some concern about high mulch rates affecting seed germination. I don’t think that’s an issue with large grass seeds, and even small seeds aren’t affected when dormant seeding with a high mulch rate since the mulch softens and breaks down over the winter. The seed can’t germinate if it’s washed away, so use enough mulch to get the job done right.

-Jim Uthe, James Devig, Dallas County, 2024

When mixing seed, we mix 10 acres worth of the fluffy grass (sideoats, big blue, Indian, little blue and Canada wild rye) and compass plant and put it in large, plastic garbage cans. Then we mix 10 acres worth of the remaining forbs in a large Rubbermaid tote and put the two slick grass seeds (rough dropseed and switch) in a 3rd tote. Our fluffy grass rate is around 10–12 bulk lbs/acre, our forbs are usually around 3–4 and slick seed is around 2 lb./ac.

-Jim Uthe, James Devig, Dallas County, 2024

When hydroseeding, we bump these rates an extra 30 to 50% at times depending upon site conditions and current climatic factors. We pretty much always seed with mulch and we typically use 1,500 lbs. of wood fiber mulch per acre. Our 3,300-gallon unit seeds about 0.9 acres pretty well with 1,350 lbs. of mulch in it (3,600 gal. of material per acre). Some people I know put 1,500 lbs. in a 3300 gallon seeder and seed a full acre, but we always seem to run a little short doing it that way.

-Jim Uthe, James Devig, Dallas County, 2024

Don’t trust your drill to meter your seed. Know your acreage and equally distribute the seed.

-Wes Gibbs, Jones County, 2024

When hydroseeding, you initially have to know how much area you are covering with a full load. With our Finn T-90, I cover a third of an acre per load. That may be more than is recommended for that size machine, but it means fewer loads per job and quicker to finish. With our 22-foot wide ROWs (average), we travel 660 feet to make that 1/3 of an acre. With practice you can become pretty accurate — arriving at 660 feet with an empty hydroseeder. If we use UNI’s recommended rates, then big bluestem at 1.5 lbs per acre, for example, uses 0.5 lbs per load. We weigh out the amount of each species needed for a 1/3 of an acre and put it in one bag ahead of time. Then we can just dump the bag in each load. This holds true for the nurse and temporary crops as well.

-Linn Reece, Hardin County, 2011

Converting Non-Native Roadsides to Native

Converting Non-Native Roadsides to Native thompsbb Tue, 03/19/2024 - 11:35

Occasionally a landowner will contact the county IRVM program to request a native planting adjacent to his/her property. If the site is conducive to a successful native planting, some counties accommodate these requests. Converting non-native vegetation to native requires eliminating the existing vegetation, usually by application of glyphosate. Cool-season grasses such as brome, fescue and bluegrass can be persistent and might require more than one application.

Kill existing vegetation with a 2% solution of glyphosate in April or May.
If thistles and other broadleaves are present, apply a Transline/Telar mix the fall prior to glyphosate in the spring.
Apply the herbicide when existing vegetation is green and growing but no more than 12 in. tall.
If there is still green grass after ten days, apply the herbicide a second time.

Consider keeping the top 4 ft. of the foreslope unsprayed, leaving it stabilized with mowable, cool-season grasses.
A native grass drill is most effective for planting into the dead stubble, disturbing the dead turf as little as possible while getting seed in direct contact with soil.
Keep the entire planting mowed during the first growing season because weeds will likely be released once the existing cover has been destroyed.
In subsequent years, spot-spray weeds as they appear.

Establishment mowing

During the first growing season, native seedlings remain small and can suffer losses due to competition by tall, thick weeds.

Mow the planting three or four times during the first growing season.
Don’t wait until the weeds are too tall.

A mowing height of 4 in. is good but to avoid scalping, 8 in. is better.

Evaluating new plantings

First-year native seedlings are small, making them hard to find and even harder to identify. As a result, people often worry or assume the planting is a failure.

If the site was drill-seeded, look for anything growing in rows.
Seedling ID books are available (see "Print Resources for Roadside Managers" in the Appendix).

If the success of a seeding is being challenged, hire a botanist to look for seedlings.
Unless a planting is washed out by heavy rains, allow two full growing seasons before giving up and starting over.