Technical Tips for Flaskers
Sterilizing disinfection tubes
Between flasking runs, autoclave your seed disinfection tubes and stoppers. This serves two purposes: the first is that it destroys any seed that may have remained behind, greatly reducing
the chances of cross-contaminating your flasks with different seed. The second is that it reduces the chance of bacterial or fungal contamination by destroying stray spores, etc.
The use of calcium hypochlorite often causes glass to be stained with white calcium depostis. The best way to remove these is to soak the glassware in dilute vinegar solution, or to use
"CLR" commercial cleaner to remove it. Using either of these acidic solutions will quickly remove any white buildup, allowing you to clean glassware quickly and efficiently.
Aluminum foil is your friend. Use it to wrap tools for autoclaving, use it to cover the lids of your flasks, use it for sterile workspaces. Replate forks can be wrapped in aluminum
foil individually, and then wrapped in large numbers to form a single "burrito" of replate forks. Razor blades, for opening green capsules, can be wrapped in foil for autoclaving. Tubes
of water can be capped with foil and held upright in the autoclave with balls of foil so they can be used for the sterile wash of seeds. Wads of sterile aluminum foil, left over from other
functions during flasking, can be used to support funnels for filtration techniques for washing seeds. A large square of aluminum foil can be wrapped up or rolled, autoclaved, and then put into the
flasking workspace to be unfolded. This sheet of foil can be used for many things, including holding a large number of seedlings from a mother flask so they can be put into replate flasks. The foil
provides a large, clean, sterile workspace for while you proceed with your work. Best of all, aluminum foil is recyclable; simply ball it up and throw it in the bin for recycling when you're
In order to disinfect your working surfaces, you may use either chlorine solutions, or alcohol. I prefer not to use alcohol, due to the fumes, expense, and flammability. It is much easier
to make a disinfection solution in the following manner using chlorine bleach.
Using a measuring cup, take 2 parts (by volume) of 5.25% sodium hypochlorite bleach. Add to this 24 parts of distilled water. Mix thoroughly. Add to this 2 parts of household vinegar (5%
acetic acid). Do NOT add the vinegar until the bleach has been diluted by the addition of the water! This solution is then added to a spray bottle. The solution is applied liberally to all surfaces
that require disinfection; use of hand towels (inexpensive white dish towels from a discount store are perfect) to mop up the excess and wipe down surfaces is recommended.
When finished with the solution, unscrew the spray head, and pump clean water through the sprayer. There is no reason to clean the reservoir; as long as the bottle is tightly sealed and
refrigerated while not in use, the solution remains stable for at least two months. However, the solution will corrode the working parts of the sprayer if left inside the pump, so flush it by
pumping plenty of water through it.
Labeling flasks can be a problem. There are several markers that write on glass and metal ("Sharpie" markers in particular); some fade with time. Be careful to make sure the
writing is still legible after applying disinfectants, or writing on surfaces that aren't clean.
Recently, we have started using black "Painters" markers, made by Hunt Manufacturing Company. The label reads "Painters Opaque Paint Marker," and it's the type with
a shaker ball in it for mixing. Although long-term tests have yet to be completed, they seem like they resist disinfection, washing, and wear with good results. Art supply stores and hobby stores
should have these.