Not always. Bacteria grow on agar at room temperature, just more slowly. An incubator earns its place when an experiment needs a steady, known temperature.
Affiliate links. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.
miniPCR bio, which makes classroom biology kits, says bacteria grow at room temperature and that visible growth can take 3 to 4 days.
For swabs from around the house, room temperature is the safer choice. Our genetics experiments guide explains why warm plates favor the bacteria that grow in people, and how to tape and dispose of them. Lab safety equipment covers gloves and goggles.
A lab strain from a kit is different. The E. coli in home CRISPR and transformation kits is a known, non-pathogenic strain, and a kit's protocol often gives a warm temperature and a timing that assume it is held steady.
Follow the temperature your kit's instructions give. Doing CRISPR at home covers what those kits contain.
For a kit's lab strain, miniPCR bio suggests a heating pad in an enclosed space, or a slow cooker kept for lab use only, aiming for 30 to 35 °C. Swabbed plates stay at room temperature. It also warns that too much heat can kill bacteria, so check the temperature with a thermometer before the plates go in.
Put the thermometer on the shelf where the plates will sit and check it again after an hour. A box warms unevenly, and the top shelf often runs warmer.
Keep plates upside down so condensation drips onto the lid and away from the agar.
A bench incubator replaces the thermometer checks with a set point. The IVYX Scientific 5 L model heats to 55 °C and can also cool to about 23 °C below room temperature.
Its inside measures 6 by 6 by 10 inches, so a stack of standard plates fits. IVYX notes a temperature difference between the bottom and the top, so keep plates on one shelf.
Pre-poured plates skip the sterilizing step. Pouring your own starts with a pressure canner.
10 pre-poured 100 mm LB agar plates and 10 sterile 6-inch swabs, made in the USA.
A 5-liter incubator that heats to 55 °C or cools to about 23 °C below room temperature, set in 1 °C steps. Runs on 110 V or a 12 V car adapter.
An incubator speeds up everything that landed on the agar, including anything you didn't mean to grow. Tape lids shut, never open a plate once it has growth, and bleach plates before they go in the trash.
