I'm trying to grow Japanese Maples from Seeds. I had over 100 germinate this year and now I think they're all dead. One the seedling reaches an inch plus, it puts out true Japanese maple leaves. After a few days to a week, they all shrivel up. The stem of the seedlings have remained erect after the death of the leaves, could they come back? What am I doing wrong. Any help would be greatly appreciated.Here's a picture of the seedling looking happy and healthy just days before the leaves just shrivelled  up and died Also my Sugar Maple seedlings and oak seedling with 8+ leaves on them also slowly dry out and eventually fall off. What could be going on? I've been moving them to much larger pots once their roots begin to develop, before they get overcrowded.

  • The one in the picture looks alright to me. How often do you water them? Are they in full sun, what is the temperature? – benn Apr 19 '18 at 18:46
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    Good call, b.nota. Jeremy, where are these seed starting trays? Indoors, out of doors, a greenhouse? Have you ever taken your starts out of doors from indoors to enjoy a bit of real sunlight? – stormy Apr 19 '18 at 21:48
  • That would answer how such healthy little starts died so quickly, leaving just stems. The other answer would be mice and rats. They will eat all the nutritious leaves and leave the stem. I would cover what few you have left with plastic domes, put a brick on top of the domes so the mice can't pry up the plastic and get inside. What is your light set up? You can wait until roots appear from the bottom of the starter cell. Easier to transplant. My vote is sunburn or rodents. – stormy Apr 20 '18 at 0:56
  • They are indoors with led grow lights and under tray heaters until the seedling starts to emerge. And us I have taken them out for sunlight. – Jeremy C. Erickson Apr 20 '18 at 0:58
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    Do those trees sink tap roots? It may be past time to get them out of starter trays. – Wayfaring Stranger Apr 20 '18 at 3:49

First, Japanese Acers do not form a taproot, so the depth of the cell, at 2 inches, shouldn't be too much of a problem. However, you say in a comment that you move them outside 'for sunlight'. This is not a good idea - seedlings, unless they germinate outdoors and are immediately exposed to an open environment, need acclimatizing to conditions outdoors, and it's not a good idea to stand them in direct sunlight suddenly. When you do move them outdoors, make sure they are not in direct sunlight for the first couple of weeks, though dappled sunlight early or late in the day is fine.

The ones that now have no leaves are unlikely to grow, but you can leave them for a while and keep your fingers crossed if you want to give them more time. Since Acer palmatum (japanese acer) does not come true from seed, it will be interesting to see what characteristics those seedlings you have left develop over time.

  • Actually I didn't move these outside until after the leaves started dying. I did however real7ze that some of the potting soil I had mixed with the starter material had fertilizer in it. Would the fertilizer kill them? @bamboo – Jeremy C. Erickson Apr 27 '18 at 13:40
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    If it was starter soil, the amount of fertilizer in that is minimal, so unless you added any, that's unlikely to be a factor. – Bamboo Apr 27 '18 at 17:48
  • I had started soil but I mixed it with miracle gro planting soil that has fertilizers @bamboo – Jeremy C. Erickson Apr 29 '18 at 2:00
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    Ah, okay, not a great idea - starter soil has either no or very little fertilizer for a reason. Once the seedlings have 2-4 true leaves, they can then be potted up into something that does have fertilizer. – Bamboo Apr 29 '18 at 9:08

Tap water or soil may be the problem, it maybe slightly salty for small Japanese seedlings. it will slow down the growth or may kill it. Fertilizer is not necessary for seedlings until 2nd or 3rd year and will kill it as well when roots are versensitive first a few months.Try to save rain water or use filter water for watering until they become large. I have grown some from seed and a few of mine died but i figure out what problem was so they are recovering now.

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