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caleb_mueller

Soil for growing western red cedar?

Caleb Mueller
4 years ago

Hello, I am growing western red cedar saplings (from seeds) indoors under a grow light, but they are not doing well and growing much slower than they should be. I used PROMIX premium potting mix soil exclusively cause I wasn't sure what else to use. Does anyone here know what is the best soil I can buy for growing western red cedar (Thuja Plicata)?

Here is a picture of my biggest sapling so far (70 days old). It is 31mm tall.



Comments (16)

  • User
    4 years ago

    Hi Caleb, welcome to the forums!

    I have to agree, you seedling looks very healthy.

    I heard good things about starting seeds in 'Pro Mix' so you should be fine there.

    As mentioned, don't over water. That's the most widely made mistake in growing.

    And any fertilizer should be used in very tiny amounts or they can cause more problems than they'er worth.

    You say 'Grow light', it is essential that you have enough light and if you didn't, I don't think your seedling would look as good as it does.

    Conifers from seed seem slow, to me anyways, so don't worry.

    There is a forum here 'Growing under lights':

    And 'Container gardening':

    That you might find interesting, talks about lighting and media used in pots/containers.

    Good Luck and keep us updated on your seedlings progress. :-)

    Caleb Mueller thanked User
  • Caleb Mueller
    Original Author
    4 years ago

    Thank you @ken_adrian Adrian MI cold Z5 and @User. I wasn't sure what the normal growth rate for red cedar is at the beginning (it's hard to find info online) but thanks to your comments I will leave it alone. @ken_adrian Adrian MI cold Z5 I can only grow it indoors as I live in university residence building and I move around alot. I am wondering, what happens when you let the plant dry out a little? Does it force the plant to grow bigger roots?

  • User
    4 years ago
    last modified: 4 years ago

    In the simplest term, roots not only need water, they also need air (oxygen). So using a pot media that has good drainage, allows the water to carry air down with it, past the roots and out the bottom of the pots drain holes. The peat in the mix soaks up and retains some of the water so the roots can draw water from it.

    The lower part of the pot retains the most moisture the longest, just from gravity and surface tension of the water. Then over several days and depending on your ambient humidity, fans running, type of media and other variables. The media drys from the top first. So although the top of the media will show drying in the first day or two, the lower/middle portions of the pot will usually stay fairly moist, generally for a few to several or more days.

    So by giving the media a chance to dry down some between watering, allowing tiny air spaces to open up again in the media, a healthy balance for the roots to grow ensues.

    Once the roots start to extend down into the media and find favorable conditions (air and water), they will continue to expand throughout.

    You can check pot moisture using a thin wooden stick called a 'tell', covered in this thread.

  • gardengal48 (PNW Z8/9)
    4 years ago

    I am concerned about what you intend to do with these seedlings in the future. They won't survive indoors much beyond the seedling stage regardless of what kind of potting soil you use.

    This is native western red cedar country and seedlings pop up constantly and grow very rapidly in their first few years. But the are growing naturally out of doors, not in a university residence :-)

    Do not allow the soil to dry completely. These trees are moisture lovers by nature and react poorly to drought or dryness. Also planting outdoors is not advisable everywhere....not all climates will suit their rather specific growing conditions.

    Caleb Mueller thanked gardengal48 (PNW Z8/9)
  • Caleb Mueller
    Original Author
    4 years ago

    @gardengal48 (PNW Z8/9) What happens if I leave it indoors even though I keep watering it, repotting it, and giving it enough light? I'm very new to all this so I have no idea

  • gardengal48 (PNW Z8/9)
    4 years ago

    They will eventually die. It is too dry and too even a temperature for them indoors and with insufficient light (whether using a grow light or not). Unless from a tropical area, conifers are not intended as houseplants and few will tolerate those conditions for long. In fact, virtually ANY plant native to temperate areas (like North America) will make a very poor houseplant for more than a few months, if that.

    Caleb Mueller thanked gardengal48 (PNW Z8/9)
  • Embothrium
    4 years ago
    last modified: 4 years ago

    Thuja plicata is the climax tree species in swamps where I am so over watering probably is not much of a threat to your potted seedlings. If you are in a suitable climate region there is probably a planting project somewhere in the local area you could pass them along to after they are bigger. Especially if you are within their native range.

    Caleb Mueller thanked Embothrium
  • User
    4 years ago

    I grow Thuja occidentalis, Picea mariana and Larix larciana, all swamp trees and you can still drown/suffocate your seedlings with too much water and not enough drainage.


    Thuja plicata gets to be very large so even if you could get one to grow indoors it would be too large in no time.

    Have you thought of bonsai Caleb?

    Caleb Mueller thanked User
  • Caleb Mueller
    Original Author
    4 years ago

    @User

    That was one of my plans depending how fast the tree grew and availability of a place to plant it where it would be safe. If there is no where I can plant it I will make it into a bonsai tree

  • gardengal48 (PNW Z8/9)
    4 years ago

    It will still need to be outside. At least 80% of the year.

    Caleb Mueller thanked gardengal48 (PNW Z8/9)
  • User
    4 years ago

    ' That was one of my plans depending how fast the tree grew and availability of a place to plant it where it would be safe. '

    With a huge forest tree such as WRC, keep in mind planting distance from buildings and such that may someday be in danger, if it falls in a high wind. :-)


    Caleb Mueller thanked User
  • Embothrium
    4 years ago

    This is the apt comment about managing these plants in pots full of soilless potting medium:

    Do not allow the soil to dry completely. These trees are moisture lovers by nature and react poorly to drought or dryness


    Caleb Mueller thanked Embothrium
  • User
    4 years ago

    Yes, you never want to wait until the media becomes 'hydrophobic'.

    That's why I mentioned using a 'tell' in one of the previous posts. It's not something you want to guess at. So many variables determine frequency of watering and those can change over time unless you have a strictly controlled environment.

    After a while, you can get to know how long to wait, but I still like to check occasionally to make sure.

    In the end, too much moisture causes more problems than too little. Unless of coarse you let things get so dry they die. I've never had that problem. :-)



    Caleb Mueller thanked User
  • ken_adrian Adrian MI cold Z5
    4 years ago

    this is what you are growing: https://duckduckgo.com/?q=Thuja+Plicata+forest&t=ffcm&iar=images&iax=images&ia=images


    notice they are not houseplants ... lol ...


    to be realistic ... you have limited time with this TREE ... so have fun with it ...but dont get to emotionally attached to it ...


    i dont recall you actually telling us where you are .. big city name ... so we can figure out if releasing it into the wild is even an option ...


    bonsai is an idea .. but most conifer bonsai i have seen.. do spend most of the time outdoors ... it might be very hard to replicate the various plant cultural requirements indoors .. especially if you are where forced air heat destroys indoor humidity.. all winter long ... and at some point it will get too big to get effective light from an indoor setup .... etc ...


    what they said about water needs or suitability of moisture levels.. but understand.. there is a giant difference between where a free range tree puts it roots to cope with the situation ... compared to the same moisture in a plastic pot ... greenhouse growers spend decades learning how to deal with it ...


    good luck



    ken



    Caleb Mueller thanked ken_adrian Adrian MI cold Z5
  • User
    4 years ago

    I agree with the amount of light needed to grow tree seedlings. Artificial lights are fine when seedlings are small and for starting seeds early when temps are too cold to have them outside.


    But as soon as it's warm enough, seedlings should be put where they can get real sun.

    And you have to expose them to that for a short duration each day or they can sunburn.


    Starting them for less than an hour a day in dappled or partial sun, for several days, increasing that time over a couple weeks, until they can adapt to the UV in full sun (6-8 hrs/day = full sun).


    On sunny spring days, I'll move some of mine from under the lights to a south facing window for ~4 hr/day (10 am-2 pm).


    Window light is filtered by the glass so it's not same as real sun, so don't think after being in a window, they can be put directly outside bc they'll sunburn.


    I do it just to give the plants more of a 'Full Spectrum' light this time of year. They're under bright light (mid-day window sun or artificial lights) constantly for 12-14 hrs a day total.

    Caleb Mueller thanked User
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