LB agar plates are a solid form of Lysogeny Broth (LB) used for culturing, isolating, and maintaining bacterial colonies. Like LB broth, they contain tryptone, yeast extract, and sodium chloride as core nutrients that support robust bacterial growth, particularly for E. coli and other non-fastidious organisms. The addition of agar provides a firm surface for the formation of colonies. This solid medium is ideal for visualizing individual colonies derived from single cells, which can then be selected for downstream molecular biology applications such as cloning or plasmid propagation.

LB agar plates can be supplemented with antibiotics or other selective agents to maintain plasmids or screen for genetic constructs. After sterilization and pouring, antibiotics are added once the medium has cooled to prevent degradation. These plates are typically stored at 4°C to maintain sterility and to avoid drying. Because they offer a stable, nutrient-rich, and easily customizable platform, LB agar plates remain a cornerstone of bacterial genetics and molecular cloning workflows.

Our LB agar plates, based on the classic Luria-Bertani formulation, are a trusted, nutrient-rich solid medium, widely used for the growth, isolation, and maintenance of bacterial strains. Since 1996, we have manufactured high-quality LB agar plates to support microbiology research across academia and industry.

We offer over 200 ready-to-use formulations, including plates supplemented with antibiotics such as ampicillin, kanamycin, and carbenicillin for selective growth, as well as animal-free agar made with soytone as an alternative to tryptone, to meet diverse research, bioprocess, and QC needs. 

Our LB agar plates are manufactured to rigorous quality control standards to ensure consistent performance and dependable shelf life across microbiology research, molecular biology workflows, and industrial applications. All raw materials we use are screened for growth characteristics before production, and the first and last plates of every finished batch are tested—across multiple strains and antibiotic conditions—to verify consistent growth performance. Each lot also undergoes sterility testing, with incubation periods tailored to the plate type, ensuring that every batch is free from contaminants.

If you don’t see the LB agar plates you need in our catalog, start a custom order or get in touch with us to discuss our flexible, custom manufacturing process. We can tailor everything from plate format to fill volume to formulation, combining up to 5 antibiotics in your custom plates, as well as additives such as glucose, arabinose, sucrose, IPTG, X-Gal, Bluo-gal, thymidine, and magnesium sulfate.