And found this on another board:
Dioecious (separate male & female plants) species plant pollen doesn't remain viable very long at room temperature and humidity.
The key to useful (viable) long term pollen storage is to dry the pollen and chill it to store long term.
Store the pollen in a glass jar or vial. Avoid plastic bags, which can breathe and are not the best for long-term storage. To reduce the water content in the pollen, place some desiccant in the bottom of the container. It's better to use an indicating desiccant. When dry, this material is blue; as it absorbs moisture, it turns pink. Using an indicating desiccant, you can tell when it has absorbed all the moisture it can. It is impossible to tell whether regular desiccant is still dry just by looking at it. Once indicating desiccant has absorbed all the moisture possible, it may turn pink, but will stop changing color. Place it in the oven and bake it until it turns blue again. This desiccant can be used over and over again. (you can reuse regular dessicant as well)
I try to put enough pollen in each glass vial to pollinate a single branch (Usually popcorn stuff). Write the variety name and date stored on both sides of the vial or on a slip of paper inside the vial so you can tell later on how old the pollen is.
Once the vial is sealed, place it in the refrigerator for a couple of days (with dessicant). Do not place it directly in the freezer because the pollen's moisture content is too high; water expansion can rupture the pollen cell walls and kill it.
Once the pollen has been in the vial for at least two days (more is better) the moisture content will be reduced enough for you to put the vial in the freezer. Once the vial is in the freezer, the pollen should be good for years. I have heard that pollen will stay viable for at least three years. (No experiments to prove this yet.)
Once you open a vial, use the pollen as soon as possible.
Pollen loses viability quickly at room temperature and even faster at higher temperatures. Pollen can stay viable at room temperature for several days. But quickly loses it's potency. (A good thing if you get a hermie in the grow room, could you imagine pollen that was good for months or years??)
If you can keep it cold, you could mail viable pollen vials to other "herb collectors". You ought to ship with freeze packs overnight, or only when the recipient is ready to use it within a couple of days of receipt.
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