Quick answer: Infield mix is the soil your skin is built from: sand, silt and clay, 4–6 inches deep over the subsoil (Rutgers, citing ASTM). Calcined clay is a kiln-fired conditioner that sits on top as a thin cap or is worked into the top 1 to 2 inches of mix (MLB groundskeeper blog). They do different jobs; conditioner can’t replace mix. Turface is a brand of calcined clay, which is neither the “clay” in your mix nor kitty litter. If your skin is low, worn or badly blended, buy mix. If the mix is sound but plays muddy, sticky or slow after rain, buy conditioner. Plenty of fields need both.
Infield Mix vs Calcined Clay at a Glance
| Infield mix | Calcined clay | Vitrified clay / expanded shale | Fine drying agent | |
|---|---|---|---|---|
| What it is | Sand, silt and clay | Kiln-fired, hard, porous clay granules | Shale or clay fired hotter; heavier, more durable | Super-fine clay that soaks up water fast |
| What it does | Firmness and footing; silt and clay set water holding | Absorbs and releases moisture, keeps soil off cleats, relieves compaction | Holds less water, breaks down slower, blows around less | Dries saturated spots |
| Where it goes | Whole skin, over the subsoil | Surface, or worked into the top of the mix | Surface; best known for warm weather | Wet spots only, then removed |
| How thick / deep | 4–6 inches (Rutgers/ASTM); about 5 on new or rebuilt baselines (MLB blog) | 1/8″ to 3/8″ on top, or the top 1–2 inches of mix | About 1/8″; more by weight than calcined (STMA) | A little at a time |
| Source | STMA; Rutgers; MLB blog | Profile; Beacon; Rutgers; MLB blog | STMA; Advanced Turf Solutions | Advanced Turf Solutions; Beacon |
On skinned infields, STMA says, professional groundskeepers use only vitrified and calcined clays.
What Is Calcined Clay? Is Turface Calcined Clay?
Calcined clay is clay fired in a rotary kiln (1200°–1400°F per Beacon Athletics; 1500°F per Advanced Turf Solutions), then crushed and screened to set particle sizes.
Yes, Turface is calcined clay. Profile Products’ Turface MVP spec sheet calls it “a calcined, non-swelling illite and silica clay,” fired at not less than 1200°F, with 74% total porosity. Profile says Turface “can absorb its weight in water,” pulling moisture from the infield clay in rain and releasing it as the field dries.
Not your mix’s clay, and not kitty litter
Raw clay in infield mix is slick when wet, often causing rainouts, and cracks and hardens when dry (STMA). Former MLB head groundskeeper Tom Burns told SportsField Management that fired clays “react in the soil more like coarse sand.” Kitty litter is simply dried clay, not a fired, permanent “ceramic” amendment (STMA), and Profile notes it’s made to break down and clump when wet.
What’s in a Good Infield Mix
Sand gives structure but shifts on its own. Clay holds moisture and color. Silt binds the mix, but STMA calls it “a necessary evil”: too much cakes on cleats and forms a hard pan. The right mix depends on how much maintenance, especially water, you can provide.
| Level / situation | Sand | Silt + clay | Source |
|---|---|---|---|
| Low-maintenance rec, park, school; Little League to high school | 70–75% | 25–30% | STMA; Bill Deacon, Luke Yoder, Paul Zwaska |
| Most fields | 65–75% | Remainder | Dr. Norm Hummel |
| Recommended target | About 60% | About 40% (20% silt, 20% clay) | Rutgers (Park and Murphy) |
| Usual starting point | 60% | 40% | Burns |
| Professional, highly maintained | 55–65% | Up to about 45% (e.g., 20% silt, 25% clay) | Hummel; STMA |
| ASTM (2007) suggested range | 60–81% | Remainder (preferably no gravel) | Rutgers |
Silt-to-clay ratio (SCR): STMA recommends 1:1 or even 0.5:1, and never more silt than clay. Beacon and Zwaska call 0.5–1.0 ideal and say 1.0–2.0 can often be improved with topdressing; Zwaska says anything above 2.0 or below 0.5 needs amending.
Rutgers warns that over 75% sand gets loose and builds lips, while under 60% plays very firm when dry. Deacon’s advice: spend “the small amount on a test” (a soils lab or Cooperative Extension office can run one, per STMA).
When Calcined Clay Helps, and When It Won’t
- It works as a surface buffer. Beacon calls calcined topdressing a buffer between cleats and firm soil underneath; it lets you walk a wet infield without soil sticking to your cleats.
- It won’t fix water retention. Rutgers: “Skin surface water retention is a function of the amount of silt and clay in the infield mix, not the amount of calcined clay on the surface.” Surface calcined clay often dries first, so some managers water needlessly.
- It often won’t help a coarse, sandy mix. Rutgers found calcined clay can make a fine-textured mix play coarser, but “the addition of calcined clay to a coarse-textured infield mix often will not improve playability.” Get a particle-size analysis of mix and conditioner first. (The MLB blog describes working conditioner into some lower silt-and-clay mixes to stabilize them.)
- There’s a tradeoff. Burns says calcined and vitrified materials relieve compaction and speed rain recovery but make the mix more erosion-prone (wind, water, play). James Hermann (CSFM) advises less sand if you’ll blend in calcined clay, which is lighter than sand and moves more.
- It wears out. Advanced Turf Solutions says all conditioners break down from dragging and can blow away: add routinely and remove fines periodically (they suggest twice a year, depending on play). Rutgers says grooming should leave a uniform 1/4″ to 1/2″ cap. See how to drag an infield.
Mounds and batter’s boxes use clayey soil or bricks over 35% clay, not conditioner (Rutgers). See our mound clay guide.
The “Quick Dry” Question
The sources disagree. Little League says to avoid “quick dry” products, which are generally smaller particles that clog soil pores and slow drainage over time. Profile, though, recommends its Turface Quick Dry as a drying agent.
They agree on handling fine material. Advanced Turf Solutions says super-fine drying agents can clog pore space and harden once dry, so remove them after the game or next day; Rutgers says to sweep up fine conditioner after play and dry it for reuse. Beacon adds:
- Remove free water first (Profile: never broom standing puddles).
- If humidity is dropping and there’s a breeze or sun, let the weather do it.
- Apply a little at a time.
- Remove any excess after the game.
Which Do You Need? Start With the Symptom
- Worn or low skin, lips, hard subgrade showing: Add infield mix (STMA), tilling the existing skin first so you don’t create layers (Dave Dwizlewski, Gail Materials). For low spots, Profile recommends the existing infield mix plus about 20% calcined clay, such as Turface MVP or Pro League Elite.
- Puddles: Fix the grade first; see our guide to fixing puddles and drainage. Short term, remove standing water first, then add calcined clay for the rest (Little League; Profile says use a cup, sponge or pump, never a broom). The MLB blog suggests filling a wet depression with calcined clay, letting it soak 15–20 minutes, then spreading it to dry.
- Hard and cracked when dry: Usually a heavy mix, too little water, or both. Working in calcined clay can help fine-textured mixes (Rutgers).
- Greasy when wet, dusty when dry: Too much silt (Beacon). Check your SCR.
- Cleats picking up mud: Not enough conditioner; STMA recommends roughly a 1/8″ layer.
- Loose, sandy, shifting: Fix the mix; calcined clay often won’t help (Rutgers).
- No water access: Stay at 70–75% sand (Deacon); STMA says vitrified clays and expanded shales suit hotter, drier climates.
How Much Turface or Calcined Clay Do You Need?
To blend it into the mix, Profile recommends 15% to 20% by volume, 4 inches deep:
Tons = area (sq ft) × depth (in) × fraction ÷ 667
Profile’s example: 9,000 sq ft × 4 in × 0.2 ÷ 667 = 10.79 tons. At 15%: 9,000 × 4 × 0.15 ÷ 667 = about 8.1 tons.
Profile’s rule of thumb for a typical mix: 1 ton per 1,000 sq ft. Bag counts are our arithmetic (1 ton = 40 × 50-lb bags):
| Field | Grass infield (Profile) | Fully skinned (double) | Higher-clay mix (+50%) | 50-lb bags, grass infield |
|---|---|---|---|---|
| Regulation baseball | 10 tons | 20 tons | 15 tons | 400 |
| Softball | 9 tons | 18 tons | 13.5 tons | 360 |
| Little League | 3 tons | 6 tons | 4.5 tons | 120 |
Topdressing only
Depths vary: 1/8″ (STMA), 1/8″ to 1/4″ (MLB blog), 1/4″ (Rutgers) and 1/4″ to 3/8″ (Beacon). By our arithmetic, Profile’s formula with a fraction of 1 gives 1,000 sq ft × 0.125 in × 1 ÷ 667 = about 0.19 tons, or roughly 7.5 bags. Vitrified products take more by weight (STMA).
For the mix itself (4–6 inches), area × depth in inches ÷ 12 = cubic feet; ask your supplier to convert that to tons.
What It Costs
Online list prices, September 2026, before tax; shipping extra unless noted. Prices vary by seller, region and volume, and the catalog and retail examples below are far apart.
| Product | Listed price | Per ton | Source / terms |
|---|---|---|---|
| Turface MVP, 50-lb bag | $50.83 | $2,033.20 | DoMyOwn, retail, free shipping listed |
| Diamond Pro Calcined Clay Pro Grade (8/16), 50-lb | $12.85 | $514 | Beam Clay 2026 catalog, F.O.B. Fort Worth, TX, plus shipping |
| Diamond Pro Calcined Clay Top Dressing (5/30) | $15.40 | $616 | |
| Diamond Pro Calcined Clay Drying Agent (16/60) | $15.75 | $630 | |
| Diamond Pro Red Infield Conditioner (2mm vitrified) | $11.55 | $462 | |
| GEORGIA RED Infield Mix / Premium, bulk | — | $75 / $125 | Beam Clay catalog, plus shipping |
| Virgin / Best Play Pro Infield Mix (Arizona) | — | $51.90 / $113.75 | West Valley Rock (Virgin, Best Play Pro) |
- Profile’s 3 tons for a Little League grass infield (120 bags by our arithmetic) cost $1,542 at Diamond Pro’s $12.85 catalog bag price (before shipping), or $6,099.60 at the $50.83 Turface MVP retail listing.
- The cheapest calcined clay here ($514 per ton) is about 6.9 times the $75 Georgia Red mix.
That gap is why you shouldn’t rebuild a skin with conditioner. On a tight budget, Beacon suggests an economical grade. Burns recommends buying mix nearby because of transportation costs.
Questions to Ask Your Supplier
- Do you test at an independent lab? Can I see results? (Deacon)
- Any stones or vegetative matter? What do you screen to? (Deacon)
- Is it the same mix every time, and can I return it if not? (Deacon)
- Can I get a client list? (Deacon, Yoder)
- Can I get a sample and data to test myself? (Yoder, Burns)
- Can you give me a sieve analysis? (Hermann) Ask for conditioners too; Profile publishes one for Turface MVP.
- What are the sand, silt and clay percentages and SCR versus my soil test? (STMA)
Where to Buy Calcined Clay and Turface
For “calcined clay near me,” start with a regional distributor. Descriptions come from each business’s own listing.
Conditioner manufacturers
- Turface Athletics (Profile Products), Buffalo Grove, IL. Makes calcined clay infield conditioners (MVP, Pro League, Quick Dry, Heritage Red), sold through authorized dealers.
- Diamond Pro (TXI / Arcosa), Dallas, TX. Calcined clay conditioners, mound and plate clays, infield mixes and drying agents.
- Pro’s Choice Sports Field Products, Chicago, IL. Oil-Dri’s sports-field division, specializing in calcined-clay infield conditioners.
Mix makers and regional distributors
- DuraEdge Products, Grove City, PA. Engineered infield mixes and topdressings, shipped nationwide.
- Eco Green Supply, Wyoming, MI. Stocks Mar-Co ball mix plus Turface MVP, Pro League Elite and Quick Dry.
- Chris Shane Company, Dayton, OH. Mar-Co mixes and conditioners for Ohio, Indiana and Kentucky, plus free field assessments.
- TMC Sports Turf, San Marcos, TX. Conditioner, drying agent, and DuraEdge and Diamond Pro materials across most of Texas.
- Valley Athletics, Portland, OR. Infield mixes, conditioners and drying agents from West Coast warehouses.
For more options, see where to buy infield dirt near you.
Bottom Line
Test your mix first. Buy infield mix to build or restore the skin and calcined clay to manage its surface. For local quotes, browse our infield mix suppliers.
