Ordinary glass battery jars holding about a gallon are good for most forms. Jars holding 2 gallons will be as good or better. For some cultures which are to be kept for a long time, like Scenedesmus, small glass jars, or dishes, with ground-glass tops are desirable. For a limited amount of material, quart or 2-quart fruit cans are very efficient. Put about an inch of pond dirt in some, clean sand in others, and in still others use a gravel bottom.
Many forms grow well without any soil or sand in the bottom of the jar.
When possible, use the water in which the algae were growing, since very few take kindly to a sudden change of water. If the material has been brought to the laboratory in a very small quantity of water, fill the jar about two-thirds full with tap water. Let the water run for 2 or 3 minutes before you fill the jar, since the water standing in the pipes is injurious, or even fatal, to most algae. Add water occasionally, only a little at a time, to compensate for evaporation. If the water has evaporated until the jar is about one-third full and you fill it nearly to the top with tap water, you are likely to kill some of the most desirable forms.