Dendrobium Question

[atcrosby]

I am seeing a lot of postings on this site and other sites about it being time to cut back on watering / feeding Dendrobiums.

I have a dendrobium someone gave me which was just repotted four weeks ago in bark medium. I have been feeding it once per week and watering twice during the week since the bark is drying out quickly. Apparently, I am doing something right in that the plant is growing new leaves, has new chutes poping up from the bark plus the existing cane is sending up a small spike.

Three questions, do i let it go with my current regimen or do I cut back?

How do you know when to cut back? Will the leaves falling off be the signal?

Will the Den require cold time (50-60 degree) temperatures to get it to bloom in the spring?

Thanks to all.

[Cynthia, Prescott, AZ]

Are you sure your Den needs cooling? If the flower spike is coming off the top of a cane, your plant is probaby a warm growing phalaenopsis type and one does not cool these off. Also, it is time for the warm types to bloom now. Keep watering and fertilizing like you have been just so long as the plant is growing. The new canes coming from the base are a sure indication the plant is no where near ready for a slow down. phal types also have fairly stiff leaves.

Now, for the ones that need cooling off, the nobile types. They bloom in spring after being cooled off, they have flowers along the length of the cane, and they have floppy leaves.

Is there a name tag on your plant? It doesn't happen often, but it does sometimes happen that one of the more unusual species shows up in home centers and the like, and these could have a very different culture than the phal types and the nobile types.

Cynthia

[atcrosby]

Thanks Cynthia -
Unfortunately, there are no tags on this plant. Most of my orchids don't have tags making difficult to know exactly what I have. Dens are new to me and I will be adding to my collection.

Do the canes ever branch or are they always a single vertical pole ?

[Cynthia, Prescott, AZ]

Single verticle pole. The nice thing about Dens is that they seem to freely re-bloom on old canes, some thing kind of rare in the orchid world. If you can't tell which type you have based on my description above, assume it is the warm growing type as this oout numbers the cool growing type by a large multiple. If you are wrong, it just means for one season you get a whole lot of keikis instead of flowers, and this can be a clue about being a nobile. Cynthia

[atcrosby]

I spoke to Jerry Meola this morning and he's selling me three Nobiles so I'll definitely have them in my collection. I am thinking they will be a challenge from everything I read on here. Of course, the payoff will be huge when they finally bloom.

What do you use for planting mediums? I am getting some bare rooted Dens so am curious how you put them into a pot. Jerry said to put them on top of lava rock or similar and let the Den take from there in digging into the rock.

Any thoughts?

[Cynthia, Prescott, AZ]

Well, I have to ask if you are going to be growing outdoors a good part of the year and have the plants getting a lot of rain? Since I grow in a greenhouse, I have complete control over the water they receive. For me, I have been spoiled by the use of a mix I got started with about 20 years ago. So, I can't stand the idea of ever going back to mix where repotting is so damaging to the roots. My mix is 3 parts small perlite, 2 parts Canadian peat, and a touch of dolomitic limestone in most cases, because the peat can be pretty acidic, and some plants don't grow well in a mix down to 4.5 ph. (7.0 is neutral). When I repot, usually once a year, I just hose the mix out and refill. Most plants don't know they have been repotted, and I can do it at any time. Dividing a plant is different, damage is usually done and the operation needs to be done at the right season. By the way, I use very small pots and water very often in the growing season. Cynthia

[atcrosby]

Interesting idea for potting materials. I have found a different approach where the dens are grown in lava rock and then a bit of moss is layered on top keep the moisture in. The plants still have plenty of air around of the roots and there is some added humidity from the moss.

I am planning on growing these inside my house sitting on humidity trays. The location they will go is a cluster of oncidiums, brassidiums and the lone dendrobium rescue (type unknown). The temperature ranges from 68-80 right now and the humidity ranges from 50-70% according to my meter.

I am just curious as to how to hold them upright until the roots begin to move into the lava rocks. Seems foreign considering all my other orchids are in some type of bark mixture. The moss will be easy in that I can simply lift it off and add new over the course of the year.

[Cynthia, Prescott, AZ]

Rock types of mix are a good match for Dens, as they are an orchid that marches accross the mix very slow, a very compact grower. This gives a very long time between repotting. A bamboo stake will probably work, then pull out and toss later. The wire hangers I mentioned in another thread are good because they will not degrade any time soon, and you may find that training the new growths to be up-right may reqiure a support of some type.

For light, I think the Dens need more light than the Oncidium complex plants. Also, many plants when dormant like higher light than normal because they grow on deciduous trees. So, see if you can't get the light level up to 40-50% of full sun, but not more. Cynthia