I scooped out a bunch of seeds from a fresh papaya (a very good one, seems like prime genetic material). I didn't have time to clean them right away, so I put them in the fridge to prevent the pieces of pulp and sarcotesta around them from decomposing and smelling until I could clean them.

My fridge is a bit unstable, and it turns out the seeds ended up below zero. Probably only by a few degrees, at worst. They would have been in that state only for a few hours. However, ice crystals had formed on them, and the pouch had hardened a little bit.

I have now taken them out to thaw. How will this episode affect germination?

And if a plant does sprout from these seeds, can it be any different because of it?

Update: They sprouted! This subject now continues on Biology SE.

  • Ever heard of this below zero seed vault? en.wikipedia.org/wiki/Svalbard_Global_Seed_Vault?wprov=sfla1
    – Rolf ツ
    May 18, 2016 at 22:30
  • @Rolfツ Sure! Actually, it's in my native country on an island I have visited. So, they store seeds in the cold. So all seeds can be stored in the cold? Graham Chiu's answer suggested many seeds have to be dried before freezing to survive it.
    – Fiksdal
    May 19, 2016 at 2:24
  • @Rolf, do they actually store tropical seeds in the seed vault, or just varieties that can survive freezing? I don't understand how tropical seeds would survive freezing.
    – Bulrush
    Jun 9, 2016 at 18:47
  • @Bulrush I wonder this too. Maybe tropical seeds would survive if dried first? Or some other preparation.
    – Fiksdal
    Jun 9, 2016 at 19:02

2 Answers 2


Seeds that need to be cold stratified with freezing are those native to regions with periods of extreme cold. This is so that the seed dormancy does not break too early with the seedling emerging in winter.

However, seeds from tropical plants do not require such mechanism, and likely have not evolved any protection for the seeds to be frozen. And usually before freezing the seeds need to be gradually dehydrated to remove as much moisture as you can. So, my guess would be that the seeds are now toast.

  • Thanks for the info. I will plant them as an experiment and report results.
    – Fiksdal
    May 18, 2016 at 20:49
  • My experiment has results, I've posted an answer.
    – Fiksdal
    Jun 9, 2016 at 10:54

They sprouted! Maybe they weren't exposed to below zero temperatures for as long as I thought.

This subject now continues on Biology SE.

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