Growing Bonsai from Seed: Summer repotting of seedlings

Lifted Ginkgo seedling

As discussed before, I like to grow bonsai from seed. In the fall I collected seeds of a wide range of species. Of all species I collected, I was most excited about seeing the ginkgo seeds germinate. I collected a bunch of seeds of the streets, something like 50 to 100 seeds in total. After cleaning them up (They have a fleshy stinky seedcoat) I placed them in a trainingpot, filled with crushed pine bark, and just placed it outside in a shaded spot for winter.

Growing bonsai from seed – Getting Ginkgo seeds to germinate

Early spring came, and nothing. I waited and waited, and finally, early may.. The seeds started to crack and roots came out. So.. In order to germinate ginkgo seed.. you do not need to do anything, except for WAIT. I was quite happy to notice many seeds germinated leaving me with a tray full of Ginkgo seedlings.

Repotting a Ginkgo seedling

In any case.. Over the summer, I have been trying to give the seedlings some space by slowly pulling a few from the large pots, and planting the seedlings up individually. In order to plant them, I was happy to notice that the pine bark was loose enough to drop of the roots once I started pulling at them. They came out with all the roots intact. Naturallly I used a little spatula to assist in pulling up the seedlings.

Growing bonsai from seed – repotting seedlings

For repotting, I look for a period with warm, yet moist weather. This will support the seedlings re-establishing themselves, without the stress of hot dry weather. After uprooting the seedlings, I place them in a bucket with water to avoind the roots drying out untill I am ready to plant them, typically withtin 15 minnutes of uprooting. Repotting seedlings mean that you have the opportunity to work on the roots and set the path for a good nebari on this pre bonsai, while the plant is still young. I normally look for the main root (which will grow into a tap root if left on) and cut the main section off. Depending on the weather and the health of the seedling, one could take off more or less.

Cutting main root on Ginkgo seedling

In the seedling in the example, normally one could cut half of the taproot off. In this case, I decided to take off more. The seedling was very healthy, the growing season is still two more months, and this week was very wet, with more rain expected for a week or so. So I went for a very short haircut. After trimming, I filled a pot halfway with substrate. And placed the seedling on top of it. This is a crucial moment: Make sure the roots are spread out evenly, and do not twist around eachother. Clip any side-roots that are too long, and fill up the container to the rim. Now you can water and fertilize as usual. Typically you will have less than 10% loss of such an operation. I normally do not loose any seedling to this.

Repotted seedlings

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3 Comments on “Growing Bonsai from Seed: Summer repotting of seedlings”

  1. Nice article. Is there anything wrong with frequent root pruning of seedlings. In my case they are Norway maples and about a month old. I can imagine that would slow down the growth short-term but shall encourages secondary growths in the root base. Would that be wise?

    1. Hi Jalil,
      Trees need to grow in order to get a trunk. Frequent root pruning would hinder that. I rootprune my your plants maybe every second year if the growth has been strong in the second year. I know some people never prune them during the initial growing out stage.

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