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xmpraedicta

Revitalizing bare root (aka rootless) dendrobiums

xmpraedicta
12 years ago

Hi everyone,

Just curious what kind of recipes you guys use to deal with bare root plants that just won't put out new growth. I bought a batch of bare root latouria and nigrohirsute dends from H&R, and potted them up (bad move) before seeing new root growth. The one dend that I didn't pot up and just threw up bare root in a clay pot in my tank (higher humidity, low light) grew roots and a new growth. Everything else has stalled.

With winter coming, I'm anxious to get something going - I'll grow them under high lights the entire winter if I have to, but I don't think they'll make it dormant through the rest of the winter.

I don't know where to buy KLN in Canada which I think is what most of you do. I do have some rooting hormone powder - I'm thinking of dissolving that in some alcohol and then mixing that with water. Any other suggestions? I grow indoors, so placing it under a bench in a greenhouse filled with buoyant humid air is not an option. What, in your opinion, is the most important factor? Warmth, humidity, light, fertilizer?

Comments (16)

  • terpguy
    12 years ago

    Fertilizer is out, most certainly! Theres no roots to take it up, so all you wind up with is expensive runoff. Never fertilize a stressed plant.

    Generally for rootless plants the key is to keep it warm and humid. Lower light is important, as you inadvertantly noticed. Putting a rootless plant in higher light forces it to consume its stores faster. Lower light than they normally take slows that process and buys the plant precious time to divert energy to vital new growth.

    I've heard of people dusting the base of their rootless plants with rooting powder. Not sure how effective that is since the plant has no way of taking it up (that I'm aware of), much like fertilizer.

  • highjack
    12 years ago

    If you have no roots, no the plant cannot take up the fertilizer but if you have leaves, yes it can use the fertilizer. It's called foliar feeding. Pay particular attention to the back side of the life, the stomata.

    I don't use rooting hormones so have no experience with them. I do use Superthrive in my fertilizer water and that is supposed to grow roots. I don't know if the rooting hormone will force a den to sprout roots in places where the roots are missing. I "think" the roots will have to come from a new growth but I wouldn't bet the bank on it.

    Warmth, lower light, humidity and crossed fingers will be your best bet for new growth. They are tough and have a strong will to live.

    Brooke

  • ttkidd
    12 years ago

    Hi Calvin,

    You can buy KLN at Bustan, down near the distillery district. I saw it on the shelves last weekend while I was in buying more hydroton.

    I used a rooting gel on a dendrobium earlier this year, and it worked great. Explosion of new root growth...unfortunately the same did not happen with the other types of orchids I used it on.

    Tyler

  • terpguy
    12 years ago

    Opening a can of worms, Brooke! foliar feeding is highly controversial for us orchidists, with data and observations being all over the map. Many people believe that foliar feeding is ineffective on orchids given their physiology and evolutionary development, and there are some that swear it works. Try at your own risk, I suppose.

    Calvin, Tyler's suggestion just reminded of a suggestion I heard recently that said to use KeikiPro on rootless plants.

  • orchid126
    12 years ago

    In lieu of any other rooting hormone available, you might try spraying some molasses water on the roots. Molasses has rooting properties.

  • highjack
    12 years ago

    I think aspirin and willow branches also have rooting properties too.

    No Terp no can of worms for this orchidist. Foliar feeding does work, particularly if you apply the solution to the underside of the leaf. Since the stomata of a leaf closes if the temps get above 90, try to apply in lower temps to be effective.

    As an experiment, rot the roots off a phal, soak the phal daily in fertilizer water as you wait on the roots to reappear and you will have a happy healthy phal the entire time that will actually continue to grow and produce leaves and stay totally hydrated.

    When Norman Fang visited my greenhouse a month ago, he said he foliar feeds his plants every two weeks. We compared the color of my leaves on mounted phals which only get foliar spray with the leaves on my potted phals and I now foliar feed them too. I guess he's an orchist who believes in the advantages of foliar feeding.

    Brooke

  • sakeofsilence
    12 years ago

    Try some seaweed, cytokinins are an incredible growth hormone. Ive had some great results with it reviving the dead. I havent ever tried superthrive, but Ive heard the stories and maybe it is worth its namesake.

  • xmpraedicta
    Original Author
    12 years ago

    Thanks for the bountiful information everyone! It's much appreciated! :) Seems like the consensus is warm and humid...Maybe I should invest in a heat pad for reptiles and just have it underneath my tank.

    Terpguy/tyler - I'll see if I can get my hands on keikipro (it's canadian, I think!). When you apply the gel, did you just put it on the eye of the dendrobium? I should have gotten the gel instead of the powder....argh. Thanks for the tip about bustan...they used to be very close to campus and I'd visit frequently, but now they've moved away and I haven't gone to them since. I'll have to check it out.

    Brooke - never knew that about the underside of the leaf. Fascinating - I'm going to try it with some of them and see what happens. The plants are dropping leaves, leading me to believe that they are over-metabolizing while rootless and thus cannibalizing themselves. Maybe a bit of fertilizer will keep them from doing that.

    Sakeofsilence - what do you do with the seaweed? And what kind of seaweed? The only kind I can think of is the kind used for sushi!
    Orchid 126: Interesting -I'm going to have to research that one...I'm worried about mold and stuff with the sugar though - have you seen that?

  • terpguy
    12 years ago

    LOL I'll take your word for it, Brooke. Like I said, observations and are all over the map, but frankly I don't really care enough to go through all that, so its not a debate I really wanna wade into. I *almost* never have issues with root rot anymore (owning to S/H and very little in the way of new purchases over the last few years), and in the rare chance I have a rootless plant, I will most likely throw it away...with exceptions made on a case by case basis (usually when I know I can get it to come back no problem). I'll keep this in mind next time I'm in the mood for experimentation, though :)

  • ttkidd
    12 years ago

    Calvin - re: applying rooting gel.

    I took a pastry brush and lightly coated the base of each PB (up to about 1/2" high) with the gel. I placed the plant in a glass vase afterwards with a little water in the bottom (not touching the plant). After a couple weeks I had lots of new roots starting to sprout. This was a Den hercoglossum.

    ...and don't reuse the brush for making pastries :)

    Tyler

  • orchid126
    12 years ago

    If I use sugar it's only once in a blue moon, so I have never had a problem with mold.

  • sakeofsilence
    12 years ago

    There are a number of kelp based fertilizers, many of which have yielded excellent results in foliar applications.(Escpecially in the realm of resuscitation) Dilute a solution a bit and apply with some RO or distilled water to the whole plant, liberally.

  • donaldb
    12 years ago

    Try the "sphag and bag" method. I's the most reliable method to attain what you want to do.

  • lucy_patrick
    8 years ago

    Hi Calvin,
    I'm new to this forum, My son and I just joined SOOS last week. He is looking for keikipro too, if you found, could you please kindly let us know? I haven't found it in canada. we have 2 orchids got problem with roots. So, if you found somewhere it need to be ordered online, I'm willing to share the shipping cost. We are living in north york. thanks!

  • ashes_of_the_fire
    7 years ago

    I had a hard cane with no roots when I bought it, I left it in it's pot of sphagnum and watered once a week, like it or not, even through the winter, it didn't grow anything more than 3 roots all winter, but with the new growth it put out in the spring it started to grow a lot more roots off of the new lead. You're likely going to have to wait a couple more years before you get flowers again, hopefully mine will bloom next fall! And wherever you do, next winter, give them the rest they need!