Quick answer: Choose an alfalfa variety in this order: winter survival first, then disease and pest resistance matched to your county, then fall dormancy, then traits and yield. Read the ratings yourself — the National Alfalfa & Forage Alliance scale defines R as 31–50% resistant plants and HR as more than 50%, so those two ratings are not the same thing. A blank cell means untested, not susceptible. And NAFA states outright that varieties are "submitted by marketers" and listing "does not imply NAFA endorsement." Independent trials matter: HarvXtra is marketed at 12–18% less lignin, but a University of Minnesota trial measured an 8% reduction in acid detergent lignin in the field.
Late summer is alfalfa seeding season across much of the country, which means thousands of growers are staring at a seed catalog trying to decode a wall of two-letter codes. The frustration is close to universal, and it is not a knowledge problem — it is a trust problem. Most of what you can read about how to choose an alfalfa variety is written by someone selling seed. This guide works from the two primary references the industry itself uses, explains what the ratings legally mean, and shows where independent university trials disagree with marketing claims. Producer quotes are verbatim and linked to the original threads.
"Its hard to see through all the marketing stuff and the variety trials seem to vary so much its confusing."
— Darton2 · HayTalk thread 19774
Contents
- Start with the two free references
- How to read resistance ratings (the part salespeople get wrong)
- Matching resistance to your actual pest pressure
- Winter survival and fall dormancy
- Traits: Roundup Ready, HarvXtra, reduced lignin and hybrids
- Let your customer pick the stem
- What the seed premium actually costs
- The 8-step selection checklist
- FAQ
Start with the two free references
Two publications from the National Alfalfa & Forage Alliance (NAFA) do most of the work, and both are free PDFs:
- The Alfalfa Variety Leaflet — a single table listing commercially available varieties with fall dormancy, winter survival, trait codes and ratings for 15 pests and diseases, including a dedicated potato leafhopper column. Ratings come from the Association of Official Seed Certifying Agencies (AOSCA) and the National Alfalfa Variety Review Board.
- The Alfalfa Analyst — a diagnostic guide to the pests and diseases themselves, authored by Dan Undersander, Fred A. Gray, Keith Kelling and Marlin E. Rice. This is how you figure out which ratings you should care about.
Producers who have worked this problem point newcomers at exactly these two documents:
"This leaflet provides various resistance levels for common alfalfa diseases and pests. I use this list to determine which variety has resistance to most diseases."
— vhaby · HayTalk thread 21911
Read one disclosure in the leaflet before you read anything else in it. NAFA states: "Varieties are submitted by marketers and listing does not imply NAFA endorsement. Variety information in this publication is that which is submitted for certification." The leaflet is a standardized comparison table, not a recommendation — which is exactly what makes it useful, as long as you know that going in.
How to read resistance ratings (the part salespeople get wrong)
This is the single most valuable thing on this page. Alfalfa resistance ratings are not qualitative grades. They are defined by the percentage of plants in the variety that are resistant:
| % resistant plants | Resistance class | Abbrev. |
|---|---|---|
| 0–5% | Susceptible | S |
| 6–14% | Low Resistance | LR |
| 15–30% | Moderate Resistance | MR |
| 31–50% | Resistance | R |
| >50% | High Resistance | HR |
Source: National Alfalfa & Forage Alliance, 2026 Alfalfa Variety Leaflet.
Three consequences fall out of that table immediately:
1. R and HR are meaningfully different. R tops out at half the plants. HR merely clears half. A grower reported being told otherwise:
"I had an alfalfa salesman tell me that the resistance ratings of resistance or high resistance were the same thing."
— Teslan · HayTalk thread 21911
NAFA's own published table says that is not correct. Same thread, same salesman, on stem nematode ratings — and the grower had just seen the counter-evidence with his own eyes:
"He sort of tried to tell me that the stem nematode rating meant nothing. However I just had attended a class on stem nematode that showed stem nematode resistant alfalfa next to unrated alfalfa and the results were very different."
— Teslan · HayTalk thread 21911
2. Even HR is not immunity. More than 50% resistant means a substantial minority of plants in that bag can still be susceptible. This is why resistant stands still need scouting, and why resistance tends to fail first where pressure concentrates — see potato leafhopper in alfalfa for how that plays out in a real field.
3. A blank is not a zero. NAFA states that "blank spaces indicate the variety has no approved rating through AOSCA." Blank means untested, not susceptible. It is genuinely missing information — which is a reason to ask the seed company, not a reason to assume the worst or the best.
Matching resistance to your actual pest pressure
You cannot get HR on everything, and chasing it wastes money on problems you do not have. The Alfalfa Analyst sorts each pest and disease into severity categories by region, and one grower turned that into a decision rule that is hard to improve on:
"Severe - you would like to have Highly Resistant (HR) for sure you want at least if available Resistant ( R )."
"Moderate - you would desire R or HR but any resistance will be appreciated."
"Mild - you can get along just fine with no resistance, but any resistance will be appreciated."
"Note: There may not be any resistant varieties for one or more of your resident pest."
— hay wilson in TX · HayTalk thread 14922
Work it in that order: look up which problems are Severe in your region first, and spend your rating budget there. Everything rated Mild locally is a column you can ignore.
The hard part is knowing your local pressure, and this is where new growers stall out:
"I can't seem to find a whole lot of knowledge about what diseases are prevalent in this area to be able to choose a resistant variety."
— FarmerCline · HayTalk thread 21911
Practical answers, in order of usefulness: your state Extension's alfalfa variety trial results (these are independent of seed-company marketing), your county Extension agent, and neighbors growing alfalfa within about 30 miles. If nobody nearby grows it, the Alfalfa Analyst regional severity maps are your best available substitute.
Expect the filtering to bite. Once you require a specific resistance, your options narrow fast — and that is the system working:
"Hmm, according to that leaflet the leafhopper resistance really narrows down my choices."
— FarmerCline · HayTalk thread 21911
Hedging with two varieties
Growers who cannot get every rating in one bag sometimes split the field. It is the same logic as blending grass varieties:
"I could plant half the lbs per acre in one variety, perhaps with better resistance package, just in case, and one that was a high yielder."
— Patmajia · HayTalk thread 14922
The grower who started that thread did exactly this — one leafhopper-resistant variety and one higher-yielding variety in the same seeding. It is a reasonable hedge when your pest pressure is uncertain, at the cost of a less uniform stand.
Winter survival and fall dormancy
These two numbers get conflated constantly. They are separate ratings measuring different things, and they appear as separate columns in the leaflet.
Fall dormancy (FD)
NAFA defines fall dormancy as "the degree of fall alfalfa growth, as a response to temperature and day length." Lower numbers shut down earlier in fall; higher numbers keep growing. The scale:
| FD rating | Class |
|---|---|
| 1–2 | Very Dormant |
| 3–4 | Dormant |
| 5 | Moderately Dormant |
| 6–7 | Semi-Dormant |
| 8–9 | Non-Dormant |
| 10–11 | Very Non-Dormant |
Source: National Alfalfa & Forage Alliance, 2026 Alfalfa Variety Leaflet.
A less obvious consequence: fall dormancy interacts with pest pressure. More dormant types can escape damage that shreds non-dormant types in the same region:
"HERE weavals are not a problem with more dormant alfalfa. They leave FD 4 alone but strip FD 7's & 8's."
— hay wilson in TX · HayTalk thread 19774
Winter survival (WS)
Winter survival is rated 1 to 6, and unlike fall dormancy it is anchored to named check varieties, so the scale is concrete:
| WS rating | Class | Check variety |
|---|---|---|
| 1 | Extremely Winterhardy | ZG 9830 |
| 2 | Very Winterhardy | 5262 |
| 3 | Winterhardy | WL325HQ |
| 4 | Moderately Winterhardy | G-2852 |
| 5 | Slightly Winterhardy | Archer |
| 6 | Non-Winterhardy | CUF 101 |
Source: National Alfalfa & Forage Alliance, 2026 Alfalfa Variety Leaflet.
Check winter survival before anything else. Every other rating is a yield or quality optimization. Winter survival is the one that determines whether you still own a stand in April — and a stand that dies takes the whole establishment investment with it. If you are seeding this month, pair this with establishing an alfalfa stand, since seeding date and winter survival are linked decisions.
Traits: Roundup Ready, HarvXtra, reduced lignin and hybrids
The leaflet uses short trait codes: R = Roundup Ready (RRA), X = HarvXtra, and H = 75–95% hybrid.
Roundup Ready
Glyphosate tolerance mainly buys you clean establishment and simpler weed control in an existing stand — see weed control in hay fields. It also enables the tank-mix convenience of adding an insecticide to a glyphosate pass. Two caveats: seed cost is higher, and if you sell into non-GMO or export channels, confirm your buyer accepts it before you plant.
Reduced lignin — and where marketing meets the trial data
Lignin is the indigestible structural component of the cell wall. University of Minnesota Extension notes it makes up about 6 to 9% of whole-plant dry weight and roughly 20% of the cell wall, and that cell-wall digestibility is negatively related to lignin. Less lignin means more digestible forage at the same maturity — or the same quality at a later cut.
There are two distinct products, and the difference matters:
| HarvXtra | Hi-Gest 360 | |
|---|---|---|
| How it was made | Transgenic — enzymes in the lignin synthesis pathway deactivated | Conventional plant breeding |
| Developed by | Forage Genetics International, Samuel Roberts Noble Foundation, U.S. Dairy Forage Research Center | Alforex Seeds |
| Claimed lignin reduction | 12–18% less whole-plant lignin | 7–10% less lignin |
| Reported benefit | Dairy trials showed +2.6 lb milk per head per day vs conventional controls | ~12% greater total tract digestibility |
Source: University of Minnesota Extension, "Reduced-lignin alfalfa varieties."
Now the useful part. University of Minnesota researchers planted reduced-lignin and reference varieties at Becker, Rosemount and St. Paul and measured them under four cutting schedules. Averaged results:
| Measure | Reduced-lignin | Reference varieties |
|---|---|---|
| Crude protein | 18.5% | 18.0% |
| Neutral detergent fiber | 42.0% | 42.9% |
| Acid detergent lignin | 7.9% | 8.5% |
| NDF digestibility | 33.5% | 29.7% |
Source: University of Minnesota Extension, first production year (2016), averaged across three locations.
Read that honestly and three things stand out:
- The measured lignin reduction was about 8% in acid detergent lignin, against a 12–18% marketing claim. Directionally real, materially smaller.
- Digestibility gain was genuine — about a 10% relative increase in NDF digestibility. Crude protein and NDF were effectively unchanged.
- Yield was not free. At Becker, reduced-lignin yields were lower than the reference varieties. At Rosemount and St. Paul they were similar. One site in three showed a yield penalty.
Where the technology clearly pays is in flexibility rather than raw quality. Minnesota found reduced-lignin alfalfa harvested on a 35-day interval delivered a 21% yield increase with only a 3% reduction in relative forage quality compared to reference varieties cut at 30 days. A longer interval also means fewer trips, lower harvest cost, less wheel traffic, less weather risk, and likely better stand persistence. If rain keeps beating you to the field, that widened window is the actual product you are buying. Pair this with when to cut alfalfa and how to read a hay test.
Let your customer pick the stem
An underrated selection criterion: who buys the hay. The two main markets want opposite things.
"The dairies really look at feed value while the horse owners look at appearance."
— hay wilson in TX · HayTalk thread 14922
That has a direct consequence for variety choice, because high-forage-quality types can carry a coarser stem:
"Some of the forage quality varieties get a puffy thick looking stem even in a o/g blend it tends to make the bale look as though it was baled old when it was not ."
— endrow · HayTalk thread 21911
Selling to a dairy on a lab test? Optimize digestibility and ignore looks. Selling small squares to horse owners who buy with their eyes? A fine-stemmed variety may be worth more than a point of relative forage quality you will never get paid for. See how to sell hay for how those markets price differently.
What the seed premium actually costs
Seed price claims vary wildly, and the spread in one thread is instructive. One grower reported paying a large multiple:
"When I was researching the brands and traits, the LHR was anywhere from 2 - 4X the cost of my non."
— mulberrygrovefamilyfarm · HayTalk thread 12049
Another grower called his seed rep on the spot and got a very different number:
"2-4 times the price sounds like a ripoff just got off phone with my DSM and our leafhopper variety is .40 lb higher than what I normally plant."
— swmnhay · HayTalk thread 12049
Bag prices in that same discussion bracket the real spread: one grower reported $210 per 50 lb for a leafhopper-resistant variety, against $180 for non-resistant. That is roughly a $0.60/lb premium, or about 17% — far closer to the $0.40/lb figure than to 2–4×.
Do the arithmetic per acre per year, not per bag. At a 20 lb/acre seeding rate, a $0.60/lb premium is about $12 an acre. Spread across a stand you expect to keep five years, that is roughly $2.40 per acre per year — considerably less than a single insecticide pass. The grower in that thread made exactly this point about amortizing seed cost over stand life, noting he routinely gets ten years out of a stand. Prices vary by region, year and dealer; always price it yourself rather than trusting any published multiple, including these.
The 8-step alfalfa variety selection checklist
- Download both NAFA PDFs — the current Variety Leaflet and the Alfalfa Analyst. Free, and they are the industry's own reference.
- Set your winter survival floor first. Non-negotiable. Everything else optimizes a stand you still have to own next spring.
- List your Severe-category pests and diseases using the Analyst plus local Extension trial data. This is your must-have rating list.
- Require HR (or at minimum R) on the Severe list only. Ignore columns rated Mild in your region.
- Pick fall dormancy for your latitude and cutting plan, remembering that more dormant types sometimes dodge pest pressure that hits non-dormant ones.
- Decide on traits deliberately. Roundup Ready for establishment and weed control; reduced lignin for harvest-window flexibility. Confirm your buyer accepts transgenic hay first.
- Match stem type to your customer — feed value for dairies, appearance for horse buyers.
- Price the premium per acre per year across expected stand life, then compare it to what you currently spend on rescue sprays.
Treat any blank rating cell as a question for the seed company rather than an assumption in either direction.
Frequently asked questions
What is the difference between R and HR in alfalfa ratings?
They are percentages of resistant plants, not grades. Per the National Alfalfa & Forage Alliance, R means 31–50% of plants are resistant and HR means more than 50%. Neither is immunity — even an HR variety can contain a large minority of susceptible plants, which is why scouting still matters.
What does a blank cell mean in the alfalfa variety leaflet?
It means untested, not susceptible. NAFA states blank spaces indicate the variety has no approved rating through AOSCA. It is missing information rather than a poor score, so ask the seed company directly if that pest or disease is a priority in your area.
What fall dormancy rating should I plant?
Match it to your latitude and cutting schedule. NAFA's scale runs 1–2 Very Dormant, 3–4 Dormant, 5 Moderately Dormant, 6–7 Semi-Dormant, 8–9 Non-Dormant and 10–11 Very Non-Dormant. Fall dormancy is separate from winter survival, which is rated 1–6 against named check varieties.
Is HarvXtra alfalfa worth the money?
It depends on whether you need flexibility. A University of Minnesota trial measured about an 8% reduction in acid detergent lignin, below the 12–18% marketing claim, with one of three sites showing lower yield. The strongest result was a 21% yield gain at a 35-day cutting interval for only a 3% quality loss.
Is reduced-lignin alfalfa genetically modified?
It depends on the product. HarvXtra is transgenic, developed by deactivating enzymes in the lignin synthesis pathway. Hi-Gest 360 from Alforex Seeds was developed through conventional plant breeding. If you sell into non-GMO or export channels, confirm which one you are buying before planting.
Should I plant one alfalfa variety or two?
One variety gives a more uniform stand and simpler management. Splitting the seeding between a strong resistance package and a high-yielding variety hedges against a pest or disease you did not anticipate, which is worth considering when local pressure data is thin.
The bottom line
Choosing an alfalfa variety is mostly a reading-comprehension problem. The ratings are real, standardized and free to look up — but they are submitted by marketers, they are expressed as percentages of plants rather than guarantees, and a blank cell means nobody tested it. Once you know that, the wall of two-letter codes turns into a usable filter: winter survival first, Severe-category resistance second, fall dormancy third, traits and yield last.
The most common failure mode is not picking the wrong variety. It is picking one without ever opening the leaflet, and taking the seed rep's summary as the whole story. One grower's honest description of his own decision is a fair summary of where most people end up:
"I couldn't find anyone to advise me, so just went with what I thought made sense."
— sedurbin · HayTalk thread 14922
You can do better than that in an afternoon with two free PDFs and your state variety trial results. And once the stand is established and producing, the hay still has to reach the feedbunk in the condition you grew it — our guide to round baling alfalfa covers protecting leaf and quality through baling, and you can browse our bale net wrap when you are ready for the season.
Sources
- 2026 Alfalfa Variety Leaflet, National Alfalfa & Forage Alliance — resistance classes, fall dormancy, winter survival, trait codes (accessed August 8, 2026)
- Dan Undersander, Fred A. Gray, Keith Kelling and Marlin E. Rice — Alfalfa Analyst, 3rd edition, National Alfalfa & Forage Alliance (accessed August 8, 2026)
- "Reduced-lignin alfalfa varieties," University of Minnesota Extension — trial data and product comparison (accessed August 8, 2026)
- "Potato Leafhopper on Alfalfa," Ohio State University Extension, Ohioline ENT-33 (accessed August 8, 2026)
Seed prices quoted by producers reflect their own regions and purchase dates and are not current market quotes. Variety ratings change between editions — always download the current year's leaflet before buying.
