I've actually given some thought to this myself, and while I haven’t personally grown a tamarack indoors, I can share some insights on what might be needed. Tamarack trees, or Larix laricina, are indeed fascinating with their deciduous conifer habit, shedding needles in the fall, which is pretty rare for conifers. Their need for a cold dormancy period might pose the biggest challenge for indoor cultivation.
To simulate their natural conditions, you'd need to consider a few factors. First, tamaracks thrive in full sunlight, so you'd have to ensure they receive plenty of direct light. This might mean positioning them near a south-facing window or supplementing with grow lights designed for trees. They also are native to cold, swampy areas, so ensuring good humidity and cooler temperatures, especially in the winter, could be crucial. You might mimic this by placing them in a cooler room or using a humidifier.
One thing to consider is dormancy. Tamaracks require a period of cold to thrive. Indoors, achieving this could be tricky unless you have an unheated space, like a garage, where temperatures consistently drop but remain above freezing. Without this chilling period, the tree might not perform well long-term.
Additionally, maintaining adequate soil moisture is critical since they're used to wetter conditions. Using a well-draining, slightly acidic soil mix and ensuring it stays moist but not waterlogged might replicate their natural habitat conditions better.
I've read that bonsai enthusiasts sometimes grow larch species in pots, so researching bonsai techniques could offer some useful guidance. Keeping them in smaller pots and pruning regularly might help manage their size indoors.
Ultimately, while it's quite demanding and might not be entirely feasible for everyone, with the right conditions and a bit of experimentation, it could be worth a try. Just be prepared for some trial and error, and remember that some conditions might be beyond what you can control indoors. If you do decide to take this on, I’d love to hear how it goes!