Petri Dishes: Complete Guide to Types, Sizes, Materials, and How to Choose
A petri dish (also spelled petri dish, Petri dish, or informally: petrie dish, pitri dish, petre dish) is a shallow, circular, flat-bottomed laboratory dish with a loose-fitting lid. It is one of the most fundamental tools in microbiology, biology, and clinical laboratory work.
Key identifying features of a petri dish:
- Shallow, flat circular bottom
- Transparent walls (glass or clear plastic)
- A lid that is slightly larger in diameter than the base
- Standard diameter: 90mm (most common), also available in 35mm, 60mm, 100mm, and 150mm
- Used to grow and observe bacteria, fungi, and cell cultures
How to select the petri dish in a lab equipment quiz: Look for a shallow, clear, round dish with a lid. It will be noticeably shallower than a beaker or flask and wider than a test tube. The lid sits loosely on top — this is a defining feature that distinguishes it from sealed containers.
How to Identify a Petri Dish (Select the Petri Dish)
When asked to select the petri dish from a set of laboratory equipment, look for:
| Feature | Petri Dish | NOT a Petri Dish |
|---|---|---|
| Shape | Shallow, flat, circular | Tall, narrow, or irregular |
| Lid | Loose-fitting, same material | Sealed or threaded cap |
| Material | Clear glass or plastic | Opaque |
| Depth | 10–20mm | Deeper |
| Bottom | Flat | Rounded or conical |
Common lab equipment it’s confused with:
- Evaporating dish — similar shape but deeper, used for heating
- Watch glass — curved, no lid, used for small samples
- Cell culture dish — similar but often treated with special coatings
Petri Dish Sizes: Standard Dimensions
Choosing the right petri dish size depends on your application and sample volume.
| Diameter | Depth | Common Use |
|---|---|---|
| 35 mm | 10 mm | Individual colonies, small-scale testing |
| 60 mm | 15 mm | Cell cultures, small experiments |
| 90 mm | 15 mm | Gold standard — bacterial cultures, microbiology |
| 100 mm | 15 mm | Larger colonies, observation work |
| 150 mm | 25 mm | Environmental testing, colony counting |
Standard petri dish size: 90mm diameter × 15mm depth. This is the most widely used size in microbiology labs worldwide.
How many ml can a petri dish hold? A standard 90mm petri dish holds approximately 25–30ml of media. A 60mm dish holds about 10–15ml.
What is the diameter of a petri dish? The most common diameter is 90mm. Other standard sizes: 35mm, 60mm, 100mm, and 150mm.
Petri Dish Materials: Glass vs. Plastic
Glass Petri Dishes
Best for: Repeated use, autoclaving, long-term cultures, research laboratories
| Pros | Cons |
|---|---|
| Reusable — reduces cost over time | Fragile, can break |
| Autoclavable up to 121°C | Higher upfront cost |
| Chemically resistant | Heavier |
| Environmentally friendly | Requires cleaning and sterilization |
| Crystal clear for observation |
When to use glass petri dishes:
- Clinical laboratories requiring repeated sterilization
- Universities and research labs with ongoing studies
- Applications requiring chemical resistance to solvents
- Long-term culture maintenance where evaporation control matters
Plastic Petri Dishes
Best for: Single-use workflows, field work, education, high-throughput labs
| Material | Max Temperature | Key Property |
|---|---|---|
| Polystyrene (PS) | 60°C | Crystal clear, lowest cost |
| Polypropylene (PP) | 121°C | Autoclavable, chemical resistant |
Can plastic petri dishes be autoclaved?
- Polystyrene petri dishes: NO — they deform above 60°C. Polystyrene petri dishes are not autoclavable.
- Polypropylene petri dishes: YES — they withstand autoclaving up to 121°C.
Are petri dishes reusable?
- Glass petri dishes: yes, when properly cleaned and sterilized
- Plastic petri dishes: designed for single use only
How are prepackaged disposable petri dishes sterilized? Most disposable plastic petri dishes are sterilized by gamma radiation before packaging. This makes them ready to use without autoclaving. Some manufacturers use ethylene oxide (EtO) sterilization.
What is the maximum temperature that petri dishes should be stored at? Store petri dishes at room temperature (20–25°C) or refrigerate at 2–8°C. Never freeze. Avoid temperatures above 40°C for plastic dishes.
Types of Petri Dishes
By Design
Single-chamber petri dishes The most common type. Used to grow a single culture. Available in glass or plastic. Standard choice for bacterial cultures, fungal growth, and general microbiology.
Double-chamber petri dishes Feature an internal divider for studying two cultures simultaneously. Used in antimicrobial testing and comparison studies.
Stackable petri dishes Designed with a rim for stable stacking. Economical for high-throughput labs. Reduces storage space.
Cell culture dishes (TC-treated) Plastic dishes with a tissue-culture treated surface for adherent cell growth. Used in cell biology and biotechnology.
By Sterility
- Sterile petri dishes — gamma-irradiated, individually or sleeve-packaged, ready to use
- Non-sterile petri dishes — for applications where sterility is not required (education, general work)
Common Uses of Petri Dishes in Laboratory Work
What is a petri dish used for?
- Bacterial cultures — growing bacteria to diagnose infections, test antibiotic sensitivity
- Fungal and mold growth — mycology, food safety testing, environmental studies
- Cell culture — growing mammalian, plant, or insect cells in biotechnology
- Microbiology research — isolating, identifying, and studying microorganisms
- Drug testing and susceptibility testing — Mueller-Hinton agar with antibiotic discs
- School laboratory projects — observing microbial growth in educational settings
- Urinalysis and clinical diagnostics — culture plates for pathogen identification
- Food microbiology — testing food products for contamination
How do petri dishes work? A nutrient medium (such as agar) is poured into the base and allowed to solidify. A microorganism sample is then applied to the surface using a loop or swab. The dish is incubated at the appropriate temperature, allowing colonies to grow and become visible for study.
Petri Dish Uses in Microbiology
In microbiology, petri dishes are used with specific agar media depending on the study:
| Application | Recommended Agar |
|---|---|
| General bacterial culture | Nutrient agar |
| Fungal and mold growth | Sabouraud agar (low pH) |
| Antibiotic sensitivity testing | Mueller-Hinton agar |
| Yeast cultivation | Yeast extract agar |
| Selective bacterial isolation | MacConkey, Blood agar |
| E. coli testing | Eosin Methylene Blue (EMB) agar |
Best petri dish for microbiology: 90mm polystyrene sterile petri dish for routine bacterial work. For autoclaving: 90mm polypropylene.
Best petri dish for E. coli testing: Standard 90mm sterile polystyrene dish with EMB or MacConkey agar.
How to Choose the Right Petri Dish
Step 1 — Sterility requirement
- Contamination-sensitive work (cell culture, clinical diagnostics) → sterile dishes only
- Educational or general work → non-sterile acceptable
Step 2 — Single use or reusable
- High-throughput or field work → disposable plastic
- Research lab with autoclave → glass or PP plastic
Step 3 — Size
- Most applications → 90mm standard
- Small samples, individual colonies → 35–60mm
- Large colonies, environmental testing → 150mm
Step 4 — Autoclaving needed?
- Yes → glass or polypropylene
- No → polystyrene (cheaper, crystal clear)
Step 5 — Packaging
- Maximum sterility → individually wrapped
- Cost efficiency → sleeve or bulk packaging
Petri Dish Brands: What You’re Paying For
| Brand | Material | Price Range | Best For |
|---|---|---|---|
| Corning | PS or borosilicate glass | $200/12 (glass), $240/800 (plastic) | Research, max sterility |
| Thermo Scientific | Polystyrene | ~$450/80 | Pharma, automated systems |
| Fisher Scientific | Medical PS | ~$400/100–500 | Education, routine lab work |
| Falcon | Crystalline PS | ~$150/500 | Cell culture, bacteriology |
| BostonMed Supply | PP or PS, sterile | Competitive bulk pricing | Clinical, research, bulk orders |
Note on pricing: Brand-name petri dishes can cost 3–5x more than equivalent OEM products with the same certifications. For high-volume labs, buying in bulk from a certified supplier significantly reduces per-unit cost.
Sterile Handling and Storage of Petri Dishes
How to store petri dishes:
- Store at 20–25°C (room temperature) or 2–8°C (refrigerated)
- Never freeze — this damages sterility packaging and dish integrity
- Keep in original packaging until use
- Shelf life: 1–3 years when stored properly
How to autoclave petri dishes:
- Only glass or polypropylene dishes can be autoclaved
- Autoclave at 121°C for 15–20 minutes
- Allow to cool before use
- Never autoclave polystyrene — it will melt and deform
How to use a petri dish aseptically:
- Work near a flame or inside a biosafety cabinet
- Open the lid as little as possible and only when adding media or samples
- Label on the bottom of the dish, not the lid
- Invert dishes during incubation to prevent condensation from dripping on cultures
Frequently Asked Questions
What is a petri dish made of?
What is the function of a petri dish?
What is the diameter of a petri dish?
Are plastic petri dishes autoclavable?
Where can I buy petri dishes?
How much do petri dishes cost?
What is the maximum temperature for petri dish storage?
How many ml can a petri dish hold?
Buy Petri Dishes at BostonMed Supply
BostonMed Supply offers sterile petri dishes in all standard sizes — 35mm, 60mm, 90mm, 100mm, and 150mm — available in polystyrene and polypropylene, individually packaged or in bulk.
Why order from BostonMed Supply:
- All sizes in stock — no backorders
- Same-day shipping on orders before 2pm EST
- Ships from South Easton, MA — fast delivery across the US
- ISO 13485 certified, FDA-registered
- Volume pricing available for bulk and recurring orders
→ Shop Petri Dishes | Questions? Email sales@bostonmedsupply.com or call 617-390-4945
