Seedlings, when to give them sun?

Hi all!

I’ve got a bunch of Japanese maples, field maple and JBP seedlings. The maples i keep in shade still and they don’t get much direct sunlight. the pines gets a bit direct sunlight through out the day. They are kept in different substrates, the field maples in akadama, the JM in compost and the pines in a compost mixed with pumice. Unfortunately most of the maples look a quite tired and i’m unsure whats going on and I have a few question on regarding seedling care aswell :slight_smile:

  1. Can they take sun at this point?
  2. how much water to they need? do need same watering as older bonsais?
  3. should i fertilize them?
  4. when can i cut of the taproot? should i wait till repotting season?

Thanks in advance for any replies :pray:

Are the solid chunks in the pots fertilizer? Your fourth and fifth photo seems as though there has been lack of root moisture(just a guess). Partial leaf death is frequently due to lack of root moisture in Japanese maples. Difficult to be more specific as photos are sometimes deceptive, as your second photo. Generally, fertilizer at the seedling stage is not advisable. If you are losing green on the leaves of JM, it may need more sun. Watering should not include periods of complete dryness. I have killed many a maple by letting them dry out. In these small containers, it is very easy for them to dry out quickly. The compost is helpful. Allow these plants to grow until there is a sizable root ball before cutting roots; perhaps a season or two. Pines usually can take more direct sun but don’t allow the fragile rootlet hairs to dry out. Don’t drown them, on the other hand. My failures with cuttings have been solely due to not checking the moisture frequently enough. Only from the photos there may be a question of powdery mildew due to the gray/white dusting on some leaves. Direct visual inspection is preferable. Starting out, it is less disheartening to obtain trees with more mature root balls, to give yourself a break. “Bonsai with Japanese Maples” by Peter Adams, 2006 is an excellent reference, although dated. Another idea is to explore for a local bonsai club with members who can eyeball with better accuracy what’s going on. Good luck.

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Thanks a lot for your reply Robert. I have been battling with the mildew for a while I’ve tried the baking powder mix and it’s seemed to work for a little bit but has now come back. I don’t any of them has been allowed to dry out. If anything I’ve been scared they was kept to wet as the compost ones rarely dries out. That’s why I’m confused. I have a few Chinese elm seedlings in pure Akadama which are loving life and growing nicely. But neither the field maple of Japanese maple I seem to be able to find out why they’re having problems.

Hi Fred - you’re right, the maples don’t look great. That said, they look like I’d expect for this time of year as the leaves can turn color and fall off at any time now when the first cold snap hits.

Some of the damage is from powdery mildew as Robert noted. Keeping the foliage dry when you water is the best thing to help with this.

And as for how much sun the trees can handle, I’d guess maples can grow in full sunshine in your area, especially this time of year. I’ll often move some trees into the sun and see how they do before moving all of them. I’ve also moved everything into the sun and then sheltered some trees when it gets really hot.

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