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I'm attempting to grow some Sequoiadendron giganteum (Giant Sequoia) from seedlings I received from a friend. I plan to bonsai them, since i don't really have the need or space for a 300ft tree.

The 2 that had leaves were green and awesome when I got them. I put them under a 480 Lumen 5000k led lamp at about 3' above, and near a heat register. I gave them 12 hours of light, and they started dying. Obviously, they weren't happy.

I have 3: #1 is still sprouting and is difficult to judge, #2 has 4 leaves and is now mostly black in the stem and curled over, and #3 has 4 leaves which have browned a bit and the stem has a small amount of brown and curling towards the top. It has 4 new leaves that haven't turned brown yet, but the top is now at 90deg from vertical.

So, realizing there was obviously a problem, I started attempting to mitigate the situation with the following:

I've been keeping the soil moist (not wet) by misting, and have attempted to raise the humidity by setting the pot above a dish of water. It being winter, I knew this could be a problem, but didn't realize how dry it was.

For light, I'm using an 800 Lumen, 5000k led bulb sitting about 12 inches from the pot, that is timed to stay on 12 hours.

3 days, and I'm not seeing any improvement.

My question is: what am I doing wrong? Is there any saving any of these, or should I get some new ones?

Photos:

one in the best shape

the other two

Thanks for the help.

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I think you are not supplying enough light. Natural sunlight is on the order of 10,000 lumens per square foot. The grow light standard is a 4 foot long, 4 or 5 tube T5 fluorescent fixture. Now there are full-spectrum LED equivalents that only use about 30% of the electricity, which means they produce less heat and can be placed closer to your trees.

Over the time span of a few weeks, the lack of light might induce yellowing foliage and maybe even leaf drop, but shouldn't be fatal to the tree. So you very well may have additional problems (possibly fungal). Regardless, your cheapest and simplest remedy is to keep the trees outside. Making bonsai is a process of wiring & bending, pruning, and grafting to achieve your ends. Indoor growing is very challenging (lighting, air flow, humidity, bugs and other pathogens, etc.) - good luck with your project.

Black color implies the cambium has died. Loss of turgidity implies more water being lost to transportation than supplied by the roots through the xylem (wood). When the cambium dies it also causes the xylem to be sealed off. So, the tops of your trees might be getting cooked by heat from your lights.

Possibly your little seedlings are just desiccating. You can put a zip loc bag over the pot and all or the top of an empty clear plastic bottle (with the bottom removed) or similar to make a little terrarium that will maintain higher humidity.

  • I guess ruling out light is good, but I'd rather know what the current problem is. Thanks for the t5 equivalent suggestion, I'll take heed of that if I can keep them alive. – FireSBurnsmuP Mar 19 '16 at 19:37
  • Black color implies the cambium has died. Loss of turgidity implies more water being lost to transportation than supplied by the roots through the xylem (wood). When the cambium dies it also causes the xylem to be sealed off. So, the tops of your trees might be getting cooked by heat from your lights. Better answers might be had if you can show a photograph. – Jim Young Mar 19 '16 at 19:46
  • there you go. I don't know why I didn't think to post photos. Thanks a lot for the help. – FireSBurnsmuP Mar 19 '16 at 20:02
  • Possibly your little seedlings are just desiccating. You can put a zip loc bag over the pot and all or the top of an empty clear plastic bottle (with the bottom removed) or similar to make a little terrarium that will maintain higher humidity. BTW, thanks for the pix. – Jim Young Mar 19 '16 at 23:18
  • After some time, they definitely died. The Zip-loc trick turned them green again, but couldn't save them. They were picky, though; they needed bag on and mist in AM, off and no water in PM. It was probably a combination of too little humidity, soil was too heavy and wet, not enough light... Thanks for your help, though! You might want to add the suggestions from your comments into the answer, particularly the information about what symptoms mean what. – FireSBurnsmuP Apr 8 '16 at 21:02

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