Blueberry seeds

Blueberry seeds

During early summer, I’ve taken several ripe Vaccinium corymbosum blueberries and kept them frozen for 6 months. During that time, they should become stratified enough to complete their dormancy. Without stratification period in the freezer, seeds would not become viable and would fail to germinate.

Washed and dried blueberry seeds
Washed and dried blueberry seeds
When blueberries thawed, I placed them into strainer and broke them into small pieces with my fingers. At the same time I was pouring cold tap water through the strainer, to clean the seeds and take out larger pieces of fruit without the seeds. I placed the seeds into paper towel and placed it on a drafty windowsill to dry. When dried, I started preparing peat moss for them to start germinating. The seeds are small, so I decided to use blender and shred the larger particles into small pieces.

vaccinium_corymbosum-seedsBlueberries need a lot of light, moisture and slightly acidic soil. They can germinate slowly, so I had to make sure to prevent mold from destroying the young seedlings. I used microwave and sterilized peat moss, before I planted the seeds. I also tried fermenting several seeds for 2 days and started germinating them in wet paper towel.

Young blueberry seedlings
Young blueberry seedlings
One month after I started, I’ve already had mold issues in both, peat and paper towel. After that I placed peat out of it’s originally planned sealed plastic bag, so It could dry out a bit. It dried out… a lot. I then noticed peat is way too compacted, so I used a toothpick to make it at least a bit softer and aerated. After a month, there were no signs of germination and after all the issues, I almost gave up. Before throwing everything into compost bin, I finally saw one tiny seedling starting to break free. After only a couple of days, more seedlings appeared and at the same time, I noticed that seeds in the paper towel also started sprouting. Despite the fact that seeds were fresh and stratified, they took more than a month to finally start germinating.


One month old seedlings.
One month old seedlings.

One month after seedlings first appeared, I decided to give them more light. They immediately started growing faster and started changing color to darker green, with more red coloring in new leaves. I used very small containers so they needed watering every two days in intense light. Before, when I placed them into completely shaded location, they only needed watering every couple of weeks.

Placing the seeds into small germinating trays soon became an issue. As seedlings started to grow, they were more and more susceptible to drought. I placed some into well fertilized peat and they died instantly, as I expected they would. Remaining seedlings were placed in clumps into pure peat on May 2nd when sun isn’t strong enough to kill them, but can fasten up their growth.

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12 thoughts on “Blueberry seeds

    1. No. I have placed whole blueberries into the freezer for 5 to 6 months. When I decided to finally grow them, I thawed them in water (room temperature) and washed out the seeds. I dried the seeds on paper towel and started germinating them in pure peat. Keeping the small containers filled with peat moist was real pain in the rear 🙂

      Stratification was done in the freezer. You do not need to keep them in the fridge after you start germination process. At that point, they need a lot of light and some warmth. I kept them low on nutrients – I might have got better results with better soil, but I haven’t sown them after the first try. I have quite enough of them already. 🙂

  1. Hi, blueberry seeds purchased through internet need to break dormancy in the refrigerator or these seeds can go directly to germinate with peat moss. Thanks for answer

    1. Hello!

      It depends. If the seeds were stratified before selling, then you don’t need to do anything, you can just sow them and wait for them to start sprouting. If blueberries were just picked and seeds got extracted right away, you still need to keep the seeds in the fridge for a few months.

      I placed blueberries into the freezer for 6 months or so and started growing them during the winter. That was enough for the seeds to break dormancy and start sprouting with high germination rate. I would most likely try stratifying them for at least a month in the fridge, You can put them into moist peat moss and place them into the refrigerator. Place the whole thing into an airtight food-grade bag to prevent the peat from drying out. Hopefully the seeds will sprout when you take them to a warm place after the cold treatment.
      If you have enough seeds, you can also try some sowing directly. If they sprout, dormancy was already broken.
      It can take quite some time for the blueberries to germinate. If it takes 1 month, I wouldn’t worry about it, if more, I would not give up. I would, however, have better hopes for the stratified seeds.
      Good luck!

    1. I don’t know if they remain viable. I’ve never tried, but I guess they should be OK. If you buy fresh blueberries, you need to freeze them for a while to break dormancy. If blueberries are frozen, they could be stratified enough, but you could keep them in the freezer for a few months just in case. Hopefully the seeds will be viable. It can take a month or so for them to sprout so be patient.

    1. Hello,

      you leave the seeds inside the blueberries and freeze them. That way the seeds will break their dormancy. You don’t need to ferment the seeds, you do need to give them a good soak in clean water when you clean out the seeds from the fruit pulp when you thaw them. By fermenting, I meant leaving the seeds inside the fruit pulp for a few days. I didn’t notice any improvement in germination rate.

  2. So you only leave the seeds in the pulp for several days. somewhere and without being put into the freezer?

      1. The seeds you fermented are placed on paper towel, are they put in the refrigerator or places near the window?

        1. I have placed the seeds in paper towel near the window.To prevent molding, I used bleach solution to sterilize the seeds before placing them into zip-lock bag. Like I mentioned before, seeds I placed into peat moss germinated just as good if not better. I would not complicate things too much again and only sow the seeds into peat moss. Make sure you don’t cover the seeds too much, the seeds are not that big and their energy reserve is low.
          It took a month or so for the seeds to germinate so don’t be too hasty and throw the pots away. They might sprout later.

          What you could try is rubbing some of the seeds gently over sandpaper to damage the protecting coat. That could speed up the germination. Perhaps I’ll try it myself too if I ever germinate blueberries again.

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