Grass vs Artificial Turf: Do NFL Favourites Cover More on Turf?
Across 7,276 NFL games, favourites on open-air turf came close to breaking even against the spread. On open-air grass they quietly bled money.
Written by Pau OliverasNFL Betting Tips specialist
- Sport
- American Football
- Question
- Do NFL favourites win and cover the spread more often on artificial turf than on natural grass?
- Survey
- NFL regular season and playoffs, 1999-2025, 7,276 completed games with closing spreads and totals; home-venue games with a listed surface
- 51.0%Favourites covered on open-air turf
- 48.4%Favourites covered on open-air grass
- โ0.7%Turf favourites flat-stake spread return
- 28.6%Turf favourites winning by 14+
Surface is one of the few venue variables in the NFL that never changes from week to week, so I wanted to know whether it moves results. The question is simple: do favourites win and cover more often on artificial turf than on natural grass? I took every home-venue game with a listed surface from 1999-2025, regular season and playoffs, with closing spreads.
The short answer is yes, modestly, and mostly outdoors. Favourites covered 51.0% on open-air turf against 48.4% on open-air grass, and backing them blind returned โ0.7% against โ6.0%. That gap is small enough to treat with care, and I'll explain why, but it shapes how I weight a favourite before I start on the matchup work behind my free NFL picks page.
Ground 1Open-air turf is the only surface where favourites cover
Across all 6,957 home-venue games with a favourite, the chalk covered 48.7% of the time. That is the baseline, and it is below half, as you would expect once the market shades its numbers towards popular sides. Open-air artificial turf is the one group that clears it comfortably, at 51.0% across 1,405 games.
Open-air grass sits at 48.4% over 3,664 games. Indoors, the same ordering holds: turf at 48.0% beats grass at 45.6%, although the indoor grass sample is only 331 games. Turf does better than grass under both roof conditions, and that consistency is what made me take the split seriously.
View the data: favourites covering the spread by surface
| Share of games, pushes excluded, 1999-2025 | |
|---|---|
| Grass, open-air | 48.4% |
| Artificial turf, open-air | 51.0% |
| Grass, indoor | 45.6% |
| Artificial turf, indoor | 48.0% |
| All venues | 48.7% |
Now the caveat, and it is a real one. Surface belongs to franchises, so the open-air turf group leans heavily on a handful of teams such as Seattle, Buffalo, New England and the New York sides after 2010. The confidence ranges of ยฑ2.6 and ยฑ1.6 also overlap, so a 2.6-point edge is a lean, not proof. What reassures me slightly is that it held in both eras: 49.3% in 1999-2012 and 52.9% in 2013-2025, against 49.0% and 47.8% on open-air grass.
Ground 2Turf favourites beat their moneyline price; grass favourites fall short
The moneyline view, using 2006-2025, compares the no-margin price with the actual strike rate. Open-air turf favourites won 69.3% of 1,076 games against a 68.2% price. Indoor turf favourites did the same thing on a smaller scale, winning 67.7% against 66.5%.
Grass goes the other way. Open-air grass favourites won 65.2% of 2,603 against 66.7%, and indoor grass favourites managed 62.2% against 65.3%. Across all venues the market was close to accurate, at 66.4% won against 66.8% priced.
View the data: moneyline favourites: priced vs won by surface
| Priced | Won | 95% range | |
|---|---|---|---|
| Grass, open-air (2,603 games) | 66.7% | 65.2% | ยฑ1.8 |
| Artificial turf, open-air (1,076 games) | 68.2% | 69.3% | ยฑ2.8 |
| Grass, indoor (299 games) | 65.3% | 62.2% | ยฑ5.5 |
| Artificial turf, indoor (1,186 games) | 66.5% | 67.7% | ยฑ2.7 |
| All venues (5,197 games) | 66.8% | 66.4% | ยฑ1.3 |
For me, this matters more than the cover rate on its own. Two separate markets point in the same direction, which makes it less likely that the spread result is simply a quirk of how the closing numbers happened to land.
Ground 3Turf favourites blow games open slightly more often
This chart splits every favourite result into three outcomes. On turf, favourites won by 14 or more in 28.6% of 3,004 games. On grass the figure was 26.2% of 4,114. The middle band, wins inside two scores, barely moves between the surfaces.
The difference sits at both ends. Favourites tied or lost outright in 32.0% of turf games against 34.7% on grass. Turf seems to turn a few would-be upsets into comfortable wins, and that is exactly the shift that pushes a favourite over a spread.
View the data: how favourites finish, grass vs turf
| Fav wins by 14+ | Fav wins by 1-13 | Fav ties or loses | |
|---|---|---|---|
| Grass | 26.2% | 39.1% | 34.7% |
| Artificial turf | 28.6% | 39.4% | 32.0% |
| All venues | 27.2% | 39.2% | 33.6% |
My trench-level reading is that a faster, truer surface rewards the team with more speed and cleaner footing up front, which is usually the favourite. Grass, particularly late in the season, does the opposite and keeps games messy and close.
Ground 4Open-air grass is where the underdog breaks even
Flat-stake returns at the listed odds bring it together. Backing every open-air turf favourite returned โ0.7%, close to the line, while the same approach on open-air grass returned โ6.0%. Across all venues favourites returned โ5.4%, so turf is clearly the outlier.
Flip it to the underdog and open-air grass returned 0.0%, against โ5.0% on open-air turf and โ0.6% across all venues. Indoors, favourites were poor on both surfaces: โ6.7% on turf and โ11.1% on grass.
View the data: flat-stake spread returns by surface
| Favourite | Underdog | |
|---|---|---|
| Grass, open-air | โ6.0% | 0.0% |
| Artificial turf, open-air | โ0.7% | โ5.0% |
| Grass, indoor | โ11.1% | +5.7% |
| Artificial turf, indoor | โ6.7% | +0.6% |
| All venues | โ5.4% | โ0.6% |
A fair price for a favourite covering 51.0% is 1.96 decimal, which is longer than the usual 1.91 at โ110. So even the best group here does not clear the vig by itself. Surface is a weighting, not a selection method.
Where to look
- Lean to outdoor turf favourites
When a favourite plays on open-air artificial turf, give it a little more credit. Those favourites covered 51.0% and returned โ0.7% when backed blind.
- Respect underdogs on grass
On open-air grass, underdogs returned 0.0% while favourites returned โ6.0%. That makes grass the natural place to look for a live dog when the matchup supports it.
- Fade indoor grass chalk
Indoor grass favourites returned โ11.1% and won 62.2% against a 65.3% price. The sample is small, but the direction is the clearest in the study.
Questions bettors ask
Do NFL favourites cover more on artificial turf?
Outdoors, yes. Favourites covered 51.0% on open-air turf against 48.4% on open-air grass from 1999-2025. The gap is modest and overlaps once you allow for sample error.
Is it profitable to bet NFL favourites on turf?
Not on its own. Backing every open-air turf favourite returned โ0.7%, because a 51.0% cover rate needs a fair price of about 1.96 rather than the standard 1.91.
Do NFL favourites get blown out more on turf than grass?
Slightly. Favourites won by 14 or more in 28.6% of turf games against 26.2% on grass, and they tied or lost in 32.0% of turf games against 34.7% on grass.
I'm Pau Oliveras, based in Barcelona, and I write the live NFL scores and weekly picks at horse-racing.tips โ pulling apart spreads, totals and the matchups that quietly decide them.
View profile โ
