Establishing an Alfalfa Stand: Seeding Rate, Depth, and Timing Done Right

By the XES Netting team — bale net-wrap manufacturer · Updated August 18, 2026 · ~32 min read

1. Gates, not a recipe

Kansas State (eUpdate issue 1116, August 13, 2026) publishes four seeding rates inside one state: "8 to 12 pounds of seed per acre on dryland in western Kansas, 12 to 15 lb/acre on irrigated medium- to fine-textured soils, 15 to 20 lb/acre on irrigated sandy soils, and 12 to 15 lb/acre on dryland in central and eastern Kansas." California publishes "20–25 pounds per acre broadcast or 15–20 pounds per acre drilled" (UC ANR 8290, 2008). Iowa State's current recommendations say alfalfa "is recommended to be planted between 15- 20 lbs per acre pure live seed" — the only one stated as PLS. What follows is a sequence of gates, each tied to a place and a year.

2. Gate 1: is this field a candidate?

Before pricing seed, triage the field. Any one of these can be a stop.

• Drainage. Current Iowa State: "field site should be well-drained. Ponding and wet soils can be detrimental to alfalfa stands." Current Ohio State splits it by season: "truly droughty soils may be a better choice for spring-established alfalfa than August-established alfalfa."
• Compaction and residue. Fix compaction now, but not with tillage at seeding: "don't overwork the soil. Too much tillage depletes moisture and increases the risk of surface crusting" (Ohio State, 2019). Current Iowa State: "minimize surface residue to reduce competition."
• Previous alfalfa. Current Iowa State is categorical: "do not plant into an old alfalfa stand to avoid suppression of the new seedlings from autotoxicity." That is Gate 7, and can mean "not this year."
• Disease history. Current Ohio State: "tillage may be necessary to control herbicide-resistant weeds or in fields with a history of sclerotinia crown and stem rot." Missouri restricts the calendar instead (Gate 6).
• Field history and manure. Record three to five years of crops, manure and amendments. Manure changes what a soil test means, so test afterwards.
• Pesticide rotational interval. The binding constraint is the plant-back interval on the previous crop's label. Current Iowa State: "ensure that there are not any residual broadleaf herbicides from the previous crop by double checking plant-back restrictions on the herbicide label." Current Kansas State: "especially true when planting alfalfa no-till into corn or grain sorghum stubble."

3. Gate 2: soil test, method and lab

Two fields with the same printed pH can need very different lime rates, because pH and lime requirement are method-dependent. A national "pH 6.5–7.0" rule falls apart here.

The target depends on state, method and subsoil. Ohio is not a range: current Ohio State (August 2026) publishes two conditional targets — alfalfa "requires pH above 6.0. Productivity will be best when pH is 6.5 (when subsoil pH > 6.0) or 6.8 (when subsoil pH < 6.0)." Current Kansas State publishes the widest band in the set: a pH "of 6.5 to 7.5," and "if the soil is acidic, add lime to raise the soil pH to 6.8 before planting." Current Iowa State: "aim for a pH that is greater than 6.5 but ideally would be closer to 6.8- 7.0." Missouri (MU G4550, undated legacy content, retrieved 2026) sets the site target as "a salt pH of 6.0 to 6.5" — salt pH runs lower than water pH on the same soil — and separately ties nodulation to a different floor: "soil salt pH should be 6.0 or above, which allows for good nodulation."

Lime rate, method and sampling depth come from your current state report. The Ohio–Indiana–Michigan recommendations were revised in 2020 as Tri-State Fertilizer Recommendations, Bulletin 974 (November 30, 2020). Ohio State: "the original publication, which came out in 1995, has been comprehensively updated." The 2020 edition moved critical levels to the Mehlich-3 extractant, made buildup "recommended but not required," and removed the drawdown range; lime is developed from the buffer pH value on your soil test results report. The 1995 edition's SMP-index lime formulas, fixed 8-inch incorporation framing and cation-exchange-capacity potassium formula are legacy and should not be applied as current. Sampling matters too: every "three to four years... with a consistent sampling depth," to a lab "using test procedures approved for the three states." Weakly buffered sandy soils are a named exception, and there is no national buffer rule.

Timing and nutrients. Missouri: "disk or plow down any needed limestone six to 12 months before seeding... In no-till seedings, apply needed lime a year in advance, because it cannot be incorporated." Current Kansas State says why: lime "is relatively immobile in the soil profile and the field will not be worked for the next 3-5 years." Ohio State (2019) makes it a scheduling gate: below pH 6.5, "apply lime now and delay establishing alfalfa until late summer." Current Kansas State publishes state nutrient thresholds — P below 25 ppm, K below 120 ppm — while Missouri warns "boron is toxic to seedlings, so you should not apply it at seeding."

4. Gate 3: variety and seed lot

Current Kansas State frames the stake: "alfalfa is a four to five-year, or longer, investment, and therefore it is crucial to ensure proper establishment." Wisconsin notes alfalfa "can remain productive in stands from four to ten years or more." Either way, buy "certified varieties with high germination percentages."

Start with your state's current trial report. Missouri states "there is no single 'best' variety for a particular location." The University of California publishes annual trial data by production region: its 2024 report covers "the Intermountain area (Tulelake), the San Joaquin Valley (Parlier) the Imperial Valley (El Centro) and the Sacramento Valley (Davis)." Read multi-year results from your own state or nearest analogue, not a catalogue.

Fall dormancy is a rated scale, and the direction matters. Current Kansas State: "purchase alfalfa varieties with a fall dormancy rating of 4-6 for Kansas," on "a scale of 1 (highest level of dormancy) to 9 (highest level of non-dormancy). The greater the fall dormancy, the less likely plants are to survive a cold winter." Check the direction before comparing states; older publications invert the convention in prose.

Match resistance and objective. Current Kansas State: resistance "to phytophthora root rot, bacterial wilt, fusarium wilt, verticillium wilt, anthracnose, the pea aphid, and the spotted alfalfa aphid is essential." Missouri prioritizes resistance to "bacterial wilt, phytophthora root rot and anthracnose" — and warns that for one Missouri disease the trait does not exist: "there is no varietal resistance to sclerotinia."

5. Gate 4: the seed-tag worksheet

Rates are published on two bases — as-published seed weight (bulk) and pounds of pure live seed (PLS) — and mixing them thins stands or wastes money. Missouri shows both: "15 pounds per acre of certified seed, which is about the equivalent of 13 pounds per acre of pure, live seed (PLS)."

The formula, in the form legumes need. University of Wisconsin–Madison Extension: "multiply percent germination times percent purity and divide by 100 to find the PLS." That suits seed whose tag prints one germination figure. Legume tags often print hard or dormant seed separately, and hard seed is viable. USDA-NRCS states the complete form: "PLS = [(%germination + % dormant seed) X % purity] divided by 100." As fractions:

• PLS fraction = purity fraction × (germination fraction + hard/dormant-seed fraction)
• Where the tag prints one total germination figure that already includes hard seed, do not add it again — the two forms then agree.
• Bulk needed per acre = target PLS rate ÷ PLS fraction
• Direction of the error: leaving hard seed out understates PLS, which inflates the bulk figure and has you buy and sow more than the target calls for — money spent for no yield effect.

Your tag and your state's seed law control which lines are printed. Coating is already counted: for coated seed "the percentage of coating material shall be included with the inert matter percentage" (7 CFR 201.51b(f)), so it has already reduced the printed purity: Wisconsin notes coating "may reduce the seed purity to 66%." Current Ohio State adds that "coated seed will be heavier, so account for its weight when calibrating your drill."

Method changes the rate. California publishes separate broadcast and drilled rates; current Ohio State ranks them without a number ("broadcast seeding is riskier than drilling"); Kansas State's 1998 handbook says to increase the rate "by one-third" for broadcasting with a packer — a 1998 Kansas number, not a national rule.

What extra seed cannot buy. A heavier rate does not fix a poor seedbed, poor depth control, autotoxic ground or herbicide carryover; those are gate failures. Current Iowa State: "research has not shown planting at a higher rate will give you a better stand. It generally leads to more seedlings dying out of the stand during the first year." UC's trial shows how fast a density advantage erodes: at the West Side Research and Extension Center, Fresno County, California, 1979–1981, rates of 10, 20, 30 and 40 lb per acre gave 12.7, 21.9, 30.0 and 35.4 plants per square foot one month after planting but 8.4, 9.5, 10.7 and 11.2 a year later. UC's Table 4.4 prints percent survival as 66, 44, 36 and 32 (the 20 lb row computes to 43.4%, printed as 44), with 1980 yields not significantly different.

6. Gate 5: seedbed and depth

Seed placed too deep is a commonly cited establishment failure, but the number is soil- and method-specific:

Published seeding-depth guidance with the state, source, year and soil scope it was written for. Not interchangeable.

Where	Source (year)	Depth as published	Scope stated
Missouri	MU G4550 (undated legacy content, retrieved 2026)	"no more than one-fourth inch deep"	No-till and prepared seedbeds alike
Iowa	Iowa State, current recommendations (no visible date; retrieved Aug 2026)	"0.25 to 0.5 inch deep"	Iowa spring seeding; cue is ~10% of seed visible
Ohio	Ohio State, late-summer guidance (Aug 2026)	"¼ or ½ an inch deep for most Ohio soils (aim for ½ to ¾ inches on sandy soils)"	Ohio soils by texture; some seed still visible
Kansas	K-State eUpdate 1116 (Aug 13, 2026)	"1/4 to 1/2 inch deep on medium- and fine-textured soils and 3/4 inch deep on sandy soils"	By texture; "no deeper than 10 times the seed diameter"
California (irrigated)	UC ANR 8290 (2008)	"0.25 to 0.50 inch" for "most California conditions"; not "greater than 0.75 inch"	Irrigated Mediterranean and desert zones

Firmness is a local test, and the thresholds conflict. Current Iowa State: "ensure your footprint does not sink deeper than 0.5 inch into the seed bed." Missouri's legacy G4550 sets the same test at roughly half that — a footprint "less than one-fourth inch deep." Same boot, two land-grant answers about 2× apart: a scope and vintage difference, not something to average away.

Calibrate and verify. We give no machine settings. Calibrate first, because "seed flow can vary greatly even among varieties, depending on the seed treatment and coatings applied," and "stop and check the actual depth of the seed in the field when you first start planting. This is especially important with no-till drills" (Ohio State, 2019). Current Iowa State expects "~10% of the seed will be visible on the top the soil."

7. Gate 6: planting date by region

There is no national "six to eight weeks before the first killing frost" rule, and spring deadlines and late-summer windows are different decisions, not one range.

Published planting windows with state, source, year, the objective each serves, and any geographic restriction the source itself attaches.

Where	Source (year)	Window as published	Stated reason and scope
California, Central Valley (arid, irrigated)	UC ANR 8290 (2008)	Fall Sept 15–Oct 31; spring Feb 1–Mar 15	From temperature and photoperiod research; a Sacramento Valley trial yielded "almost 4 tons per acre" more in the first season for September
Kansas	K-State eUpdate 1116 (Aug 13, 2026)	Northwest "as early as August 10"; southeast "until mid- to late-September"; elsewhere "late August or early September"	Development-based: plant "early enough to have three to five trifoliate leaves before the first frost." Late summer and early fall are "often the best alfalfa planting windows in Kansas due to lower weed pressure"
Missouri	MU G4550 (undated legacy content, retrieved 2026)	Spring by late March or early April (south), mid-April (north); late summer in late August or early September	Spring cutoff "so seedlings are well developed before the hot, dry summer"; late summer "so the seedlings become winter-hardy." Restricted: late summer applies "north of the Missouri river"; "late summer seedings are not recommended south of the Missouri river in areas where sclerotinia crown and stem rot has occurred." There is "no varietal resistance to sclerotinia"
Ohio	Late summer: Ohio State citing Ohio Agronomy Guide, 16th ed. (Aug 2026). Spring: Ohio State (Apr 30, 2019)	Late summer: "August 1st and August 15th for northern Ohio," "August 1st and August 30th for southern Ohio." Spring: "finish seeding by late April in southern Ohio and by the first of May in northern Ohio"	The split follows "the later timing of first frosts in southern Ohio, since a frost before successful root system establishment will limit your new seeding's ability to overwinter"
Iowa	Iowa State, current recommendations (no visible date; retrieved Aug 2026)	No calendar dates published; "timing is crucial for spring planting"	Bracketed by risks, not a date: "planting too early can expose young stands to damaging frost, while planting too late can lead to greater potato leaf hopper and weed pressures"

The rule that goes with a late-summer window. Current Ohio State: "do not plan to harvest August-planted alfalfa until next spring—cutting in fall will reduce winter survival." Carry a spring-seeding harvest rule into an August seeding and you cut in October and lose the stand.

Frost seeding alfalfa. This is a published method with published rates, and also the least reliable option. University of Wisconsin–Madison Extension: frost seeding is "less reliable than seeding with a drill," but it "is commonly used to increase plant diversity, forage yield, and reduce weed pressure." Wisconsin publishes a rate table that includes alfalfa: 5–8 lb per acre seeded alone, 3–4 lb per acre as part of a seed mixture, with 4–6 expected established plants per square foot. It publishes mitigation as well as risk: less dormant varieties germinate early and can be killed by low temperatures, whereas "the more dormant varieties tend to germinate later in the season escaping the risk of winterkill." Missouri gives the window — "you should frost-seed in January or February" — while still ranking it last. What it does not do is get around Gate 7. University of Minnesota Extension, in guidance for renovating established horse pastures: "don't frost seed alfalfa in cases where alfalfa plants already exist in the stand."

8. Gate 7: autotoxicity

Alfalfa releases compounds that suppress establishment of new alfalfa seedlings. Wisconsin Extension: they "inhibit the ability of the root radicle to elongate," and the effect "will persist throughout the life of the plant." General articles blend two separate decisions: repairing a failed new seeding is not the same as rotating out of an established stand.

Autotoxicity guidance by scope and source.

Scope	Source (state)	Guidance as published
Failed or very young seeding (one year old or less), any cause	Univ. of Wisconsin–Madison Extension	Plants "one year old or less" hold less toxin, so "failed seedings or even new seedings that winterkill can be seeded back to alfalfa with little yield reduction." The general age rule
Winterkilled stand, being spring seeded back to alfalfa	Univ. of Wisconsin–Madison Extension	A winterkilled stand behaves "similar to that of a stand killed in early spring," so there will be "significant yield reductions if these stands are spring seeded back to alfalfa unless they are less than two years old." That two-year figure belongs to this case only, not to the general age rule above
Thickening an existing stand	Univ. of Wisconsin–Madison Extension, citing Missouri research; Iowa State (current)	Wisconsin: "interseeding alfalfa to thicken alfalfa stands is not likely to be successful and is not recommended" — seedlings within 8 inches of an old plant did not survive, so "a stand density as low as 0.8 plants/ft2 would be enough for the autotoxic zone to cover an entire acre," which is "approximately four times thinner than the minimum level of three plants per square foot suggested for economic alfalfa production." Any stand worth keeping is already too dense to thicken. Exception: large dead areas, or seedings under a year old. Current Iowa State, offering no interval: "do not plant into an old alfalfa stand to avoid suppression of the new seedlings from autotoxicity"
Terminating an established stand, then reseeding alfalfa	Univ. of Minnesota Extension; Univ. of Wisconsin–Madison Extension	Minnesota: "allow at least one year between terminating an old alfalfa stand and reseeding alfalfa," and, for winterkill repair specifically, "delaying spring reseeding two to four weeks after tilling a killed stand is not an effective strategy to alleviate autotoxicity." Wisconsin: "rotate to some other crop such as corn for at least a year"

Why the intervals differ — and how widely. Wisconsin: persistence "is a function of soil type, temperature, and amount of rainfall" — acute but short-lived on sandy soils that leach, "less pronounced but longer lasting" on heavier textures, and "greater in no-till fields than those moldboard plowed." The research disagrees by state: Michigan work where "a three-week waiting period was all that was required," Missouri work where "yield was reduced 8%" at three weeks, Wisconsin studies showing "yield reductions of 30% and 70%" at 4 and 2 weeks after plow-down. The clearest measure of how little consensus exists is a 1996 survey of forage specialists in 40 states: recommended minimum rotation intervals ranged from two weeks to 24 months. Wisconsin adds the honest limit: "it is not known what the threshold is below which autotoxicity is not a concern."

9. Gate 8: inoculant

Two current land-grant positions, and they differ. Current Kansas State: "most alfalfa seeds are pre-inoculated these days, so you don't need to worry about inoculation." Colorado State University Extension is more cautious: native rhizobial populations "often are less effective in nitrogen fixation potential," and "when in doubt... it is a good practice to apply inoculum." UC ANR 8290 (2008) uses field history: "soils without a recent history (within the past 10 years) of alfalfa may need to be inoculated." Strain matters too: "each legume requires a specific species and strain of rhizobia."

Pre-inoculated seed is perishable — and re-inoculating it is a manufacturer question, not a default. Colorado State: "keep preinoculated seed in a cool environment during shipping and storage. Use the seed within one year of inoculation, or reinoculate it prior to planting." Before acting on the second half of that sentence, read the seed treatment: "most seed disinfectants, including fungicides, can be toxic to rhizobia bacteria." Colorado State tells you not to apply inoculum to bactericide-treated seed unless you use a resistant strain, and to avoid inoculum premixed with pesticides. The governing instruction sits with the product: "check with the inoculum manufacturer regarding combining products."

Storage, expiry and verification. Colorado State: "most inoculum manufacturers put an expiration date on the package. Do not purchase outdated inoculum," and refrigerate peat-based inoculum, with "short-term storage at temperatures below 60 degrees F" acceptable — the qualifier is part of the sentence. Verify by cutting nodules: one "actively fixing nitrogen will be pink to reddish when cut open, rather than tan (ineffective) or green (dying)."

10. Gate 9: companion crop, weeds, insects

Companion crops are source-scoped, and the rates have moved. Ohio State (2019) ties them to erosion risk: "a small grain companion crop can reduce the erosion hazard," planted "at 1.5-2.0 bu/A," removed "as early pasture or silage," with no added nitrogen. Missouri uses "one bushel per acre," harvested "no later than the boot stage." Current Iowa State is now the lowest of the three: plant the companion "at a reduced rate, less than ½ bushel per acre, as a higher rate can decrease alfalfa production and stand the following years. The alfalfa should be planted at a full rate." Its exit rule: "harvest at or before the boot stage, and if not harvesting for forage, terminate before 6 inches."

Insects after a killed sod: know the mechanism, then get a local threshold. Seeding into killed but un-tilled sod puts seedlings into a field that still contains living roots, and current Ohio State names the consequence: "root-feeding insects can become a problem when alfalfa seedlings emerge in a field that has pre-existing living roots." Missouri's legacy G4550 prescribes a soil insecticide for every killed-sod seeding; that is a 1990s-vintage universal prescription and we do not republish it as current. Treat killed sod as a flagged risk triggering current local scouting and a threshold decision with a certified crop adviser, under the current label.

Weeds and insects: scout on a schedule, decide on thresholds. Ohio State (2019): "during the first 6 to 8 weeks after seeding, scout new seedings weekly... Potato leafhopper damage on legumes in particular can be a concern beginning in late May to early June" (Ohio timing). Missouri is threshold-based: "spray or cut when insect populations reach economic thresholds."

11. Stand verification

Counting turns "it looks thin" into a decision with a number behind it. Counts mean nothing without three labels: what was counted (plants or stems), when (stand age), and where it came from.

Published stand-count benchmarks with source, place, unit and the stand age each applies to.

Stand age	Source (place, year)	Benchmark as published
Emergence (3–4 weeks), then first two production years	Cornell Cooperative Extension, North Country Regional Ag Team (Midwest and East; PDF metadata dated April 2, 2018)	Denominator first: "at a seeding rate of 15 pounds per acre you will have 75 seeds per square foot. After emergence is completed in three or four weeks only about 45 alfalfa seedlings will be present" — roughly 45 seedlings per square foot from 75 seeds. Optimum: "20 to 35 plants per square foot in the establishment year... 12 to 20 [first production year] and 8 to 12... in the second"
End of first year / fall of seeding year	Iowa State (current, no visible date, retrieved Aug 2026); Univ. of Minnesota Extension (three MN sites, fall dormancy 4 and 5)	Iowa: "the goal should lead to 20-30 seedlings per square foot by the end of the first year." Minnesota: "25-30 plants/ft2 or more is recommended in fall of the seeding year," with a "significant yield decline" later below "10 per square feet"
Seeded last year, or older than one year	Univ. of Wisconsin–Madison Extension (Wisconsin, updated April 8, 2025)	Seeded last year: "at least 12-20 plants per square foot." Older than one year and below "5-6 plants per square foot": terminate and rotate to a non-alfalfa crop
Established stands; new irrigated seedings	MU G4550 (Missouri; undated legacy content); UC ANR 8290 (California, 2008)	Missouri: seedings "initially have 15 or more plants per square foot"; later, "pure stands with three or more plants per square foot can maintain high productivity." California: rates "typically result in 20–50 plants per square foot"

Stem counts past the seedling stage — and why 55 is a Wisconsin number. Wisconsin Extension (April 8, 2025): "count the number of stems over 2" tall, then divide by two to get stems per square foot... with any number above 55, stem density is not the limiting factor for yield that year." Minnesota tested the same relationship on its own sites and got a different optimum: "stem densities of about 70 stems/ft2 maximized forage yields in this study, a somewhat higher number than the 55 stems/ft2 reported for Wisconsin. At 55 stems/ft2, yields in this study were about 80% of the maximum yield." So 55 is a Wisconsin decision threshold, not a universal ceiling; Minnesota also found stem density "explained less than 50% of the changes in yield."

Uniformity, roots and crowns. An acceptable average with half the field bare is a different problem from an evenly moderate stand, so record where you counted. Then dig. Wisconsin: "dig down to at least 6" depth... Winter killed roots will be soft, stringy, and gray or brown." Its combined trigger: below the stand thresholds "AND if more than 30% of a field is affected by root rot."

12. First harvest in the seeding year

If it was seeded in late summer, there is no seeding-year harvest. Current Ohio State: "do not plan to harvest August-planted alfalfa until next spring—cutting in fall will reduce winter survival." Everything below is for spring seedings.

There is no universal "cut at early bloom" rule for a spring-seeded stand either. Ohio State (2019): "the first harvest of the new seeding should generally be delayed until early flowering of legumes." Missouri G4550, for spring-seeded stands: "take the first harvest at the mid- to full-bloom stage," plus a fall rest — "do not cut or graze between Sept. 15 and Nov. 1" — a Missouri window, not a national one.

13. The record to keep

One file per field, per seeding. Record: field ID, acres, sampling date and depth, lab and state-list status, pH with the method named (water or salt), buffer value, P and K with the extraction method used; lime and fertilizer product, analysis, rate and date; variety, lot number and the seed tag itself (purity, germination, hard/dormant seed, inert matter, coating status, test date) with your calculated PLS and target PLS rate; inoculant product, lot, expiry and whether the seed was pre-inoculated or treated; drill calibration and depth checks; planting date, moisture, method and companion crop rate; every chemical applied, with the governing label restriction; and dated stand counts with the unit (plants or stems).

14. Limitations of this guide

• Compilation, not authorship. Everything above is quoted from a named land-grant Extension or USDA-affiliated source. Where a source carries no publication date we say so.
• Regional coverage is incomplete. Sources cover California, Kansas, Missouri, Iowa, Ohio and the Tri-State region, Wisconsin, Minnesota, Colorado and the Northeast. The Southeast, Pacific Northwest, northern Plains and Intermountain West are not represented.
• Source vintage varies, and some is legacy. Current-facing: Kansas State eUpdate 1116 (Aug 13, 2026), Ohio State late-summer guidance (Aug 2026), Iowa State seeding recommendations (undated, retrieved Aug 2026), Wisconsin stand evaluation (Apr 8, 2025), UC variety trials (2024). Older but dated: UC ANR 8290 (2008), Cornell (Apr 2, 2018 per PDF metadata), Ohio State forage establishment (Apr 30, 2019). Legacy, used only where labelled: Tri-State 1995 (superseded by Bulletin 974, 2020) and MU G4550 (undated).
• One source is browser-only. MU G4550 returns HTTP 403 to automated clients; its text was verified via a public web-archive capture. A site's "reviewed" stamp is not evidence the underlying data was refreshed.
• No photograph — see the image note below.

Frequently asked questions

What soil pH does alfalfa need?

It depends on your state, on the test method, and in Ohio on your subsoil, so there is no single number. Current Ohio State sets two conditional targets: 6.5 where subsoil pH is above 6.0, and 6.8 where subsoil pH is below 6.0. Current Kansas State gives 6.5 to 7.5 and says to lime to 6.8 before planting. Current Iowa State says above 6.5, ideally closer to 6.8 to 7.0. Missouri G4550, legacy and undated, targets a salt pH of 6.0 to 6.5, and separately says salt pH should be 6.0 or above for good nodulation.

How do I calculate pure live seed from a seed tag?

USDA-NRCS gives the form legumes need: pure live seed equals germination plus dormant seed, multiplied by purity, divided by 100. As fractions, the PLS fraction equals purity times the sum of the germination and hard or dormant seed fractions, and bulk seed per acre equals your target PLS rate divided by that fraction. If your tag prints one total germination figure that already includes hard seed, do not add it twice. Leaving hard seed out understates PLS and makes you buy more bulk seed than you need. Coating is already counted in the inert matter under federal seed regulation.

How deep should alfalfa be seeded?

The published depth depends on state, soil texture and method, so it is not one number. Current Iowa State says 0.25 to 0.5 inch. Current Ohio State says a quarter or half inch on most Ohio soils, and a half to three quarters of an inch on sandy soils. Current Kansas State says a quarter to a half inch on medium and fine textured soils, three quarters on sandy soils. Missouri G4550, legacy and undated, says no more than one fourth inch.

When should I plant alfalfa?

Use your own state's current window, and do not read a spring deadline and a late-summer window as one range. Current Ohio State gives August 1 to 15 for northern Ohio and August 1 to 30 for southern Ohio; current Kansas State gives as early as August 10 in the northwest through mid- to late September in the southeast, with three to five trifoliate leaves needed before frost. Ohio spring seeding finishes by late April in the south and about May 1 in the north. Missouri restricts late-summer seeding to north of the Missouri River, and not south of it where sclerotinia has occurred. Ohio also says an August seeding should not be harvested until spring because a fall cutting reduces winter survival.

Do I need a nurse crop or companion crop with alfalfa?

Not always; the reason for using one controls the choice. Current Iowa State recommends less than one-half bushel per acre where a companion crop is used, because higher rates can reduce later alfalfa production, and says to harvest it by boot stage or terminate it before six inches. Ohio State's 2019 guidance uses 1.5 to 2.0 bushels per acre on erosion-prone conventional seedings and removes it early as pasture or silage, while direct seeding is preferred where erosion risk is low. Missouri's legacy guidance uses one bushel per acre. These are state- and objective-specific examples, not a national oats prescription.

Can I reseed alfalfa into a field that just had alfalfa?

It depends on the age of the stand you removed and on how it died. University of Wisconsin-Madison Extension says failed seedings, or new seedings that winterkill, that are one year old or less can be seeded back to alfalfa with little yield reduction, and that where a stand seeded last year is thinner than 12 to 20 plants per square foot you can reseed without autotoxicity concerns because it is only a one year old stand. The age is the reason, not the low plant count. A separate Wisconsin rule covers winterkilled stands being spring seeded back to alfalfa, where the limit is under two years old. University of Minnesota Extension says allow at least one year after an established stand, and that delaying spring reseeding two to four weeks after tilling is not an effective way to alleviate autotoxicity. A 1996 survey of 40 states found intervals from two weeks to 24 months.

My new seeding came up thin. What do I do first?

Count and dig before you spend anything else. Compare plants per square foot against your state benchmark for that stand age, count in several areas so you know whether the field is uniformly thin or patchy, and dig plants to check roots and crowns. Current Iowa State targets 20 to 30 seedlings per square foot by the end of the first year. University of Wisconsin-Madison Extension, updated April 8, 2025, treats an average above 55 stems per square foot as not yield limiting. Treat 55 as a Wisconsin threshold: Minnesota found about 70 stems per square foot maximized yield, with 55 giving about 80 percent of maximum.

Sources

• Kansas State Univ. Research and Extension, Tips for Fall Planting of Alfalfa, eUpdate 1116 (August 13, 2026)
• Ohio State Univ. Extension, Summer Plantings for Alfalfa (August 13, 2026), citing the Ohio Agronomy Guide, 16th ed.
• Iowa State Univ. Extension and Outreach, Alfalfa Seeding Recommendations (undated; retrieved August 2026)
• Univ. of Wisconsin–Madison Extension, Evaluating alfalfa stands for profit in spring 2025 (updated April 8, 2025)
• Univ. of California, 2024 California Alfalfa Variety Trial Results (PDF)
• Ohio State Univ. Extension, Tri-State Fertilizer Recommendations, Bulletin 974 — current edition (November 30, 2020)
• Ohio State Univ. Extension, Use 2020 Tri-State Fertilizer Recommendations (June 24, 2020)
• USDA Natural Resources Conservation Service, Seed Quality: Pure Live Seed Calculations (PDF)
• 7 CFR 201.51b, Purity procedures for coated seed (via Cornell LII)
• Univ. of Wisconsin–Madison Extension, Understanding autotoxicity in alfalfa (undated; has the 1996 40-state survey)
• Univ. of Wisconsin–Madison Extension, Seeding alfalfa fields back into alfalfa (undated)
• Univ. of Wisconsin–Madison Extension, Pure live seed (undated)
• Univ. of Wisconsin–Madison Extension, What species work best for frost seeding? (undated; has the alfalfa rate table)
• Univ. of Minnesota Extension, Reducing autotoxicity in alfalfa (undated)
• Univ. of Minnesota Extension, Stem and plant density as predictors of alfalfa yield (undated)
• Univ. of Minnesota Extension, Frost seeding forages into established horse pastures (undated) — scope: horse-pasture renovation
• Ohio State Univ. Forages team, Establishing New Forage Stands (Sulc; April 30, 2019)
• Cornell Cooperative Extension North Country Regional Ag Team, Alfalfa seeding rates revisited (PDF, no printed date — metadata gives April 2, 2018)
• Univ. of California ANR, Alfalfa Stand Establishment, ANR Publication 8290 (2008; PDF)
• Colorado State Univ. Extension, Legume Seed Inoculants (undated)
• Univ. of Missouri Extension, Alfalfa (G4550) (undated, legacy; retrieved 2026 — the live page returns HTTP 403 to automated clients, so text was verified via a web-archive capture)
• Tri-State Fertilizer Recommendations, 1995 edition, hosted by Ohio State Univ. Extension (PDF) — superseded by Bulletin 974 (2020)
• Soil Science Society of America, North American Proficiency Testing (NAPT) program

Image note: no photograph is published with this guide. The photograph previously credited here showed an established flowering alfalfa field, which misrepresents a guide about seedling establishment. Correctly identified, credited seedling photographs do exist at sources cited above — for example Kansas State's "Alfalfa seedlings. Photo by Doohong Min, Kansas State Univ." What we have not obtained is republication permission or a licence, so we publish none: a permissions gap, not an identification gap.