Denrobium Nobiles,when to cease watering?

[Lucinda Brown]

Hi, I've read that you should stop watering Nobiles on November 1, entirely., until flowering begins. Then I have also heard that you should still water them enough to keep canes from shriveling after Nov. until they flower. Can anybody clear this up for me?

[Cynthia, Prescott, AZ]

Well, I'm afraid I am going to confuse things even further. I have only recently started growing these and have only been thru one winter with a few of these so far. My notes, based on Bakers book on Dendrobiums indicate that the plants need:

1) When the plant stops growing, no new leaves forming in the center of the new growth, go from a fairly wet watering to a decidedly wet/dry pattern.

2) December thru March, the plant needs to be cooled down. Mine go into a cold frame that is warm in the day, but very cool at night, down to ~36F occasionally.

3) In March, dry the plant off much more.

Well, I did get blooms, but the plants themselves were not in very good shape to start, so next spring will tell the tale. Cynthia, Prescott, AZ

[jerrymeola]

I grow a lot of nobiles and am a distributor of Yamamotos Dendrobiums (the best nobile grower in Hawaii)

My advice is a combination of my experience and suggestions from Koichi at Yamamoto.

Not all nobiles are the same. I have my favorite Den Dream Ace which flowers twice a year never needs to have water or fertilizer reduced. I fertilized one every day last year and fertilized every week and was rewarded with 1000 flower buds.

Yamamoto Dens are more typical in that they bloom once a year setting buds in Sept to Dec for flowering in Dec to April. Reducing fertilizer after August or at latest September is critical. Koichi says this is the main reason from poor results with his orchids. He was not as concerned about the water level although he does reduce it in the fall winter. Nitrogen build up in nobiles prevent flowering so fertilizer should be stopped completely after August.

Also nobiles take very high levels of light. Yamamoto grows his outdoors all the time without any shade. Light level here in Florida are higher than Hawaii so I reduce the light levels in July to September in the afternoons, otherwise I try to give full sun all day.

Nobiles develop flowers on the stems so they should be placed widely apart so that light can reach the bottom of the stem. We commercial growers are always short of space but crowding the plants will produce flowers mostly on the top third of the plant whereas flowers can start as low as the base of the plant. Hobbyist can grow a better looking plant then one purchased commercially so you have a low to look forward to in the years to come.

[latsyrc]

I've only got one dendrobium, but it has buds on a stem, not coming straight from the main stalk. Am I supposed to reduce fertilizer or water on that one in the fall?

[Cynthia, Prescott, AZ]

If the flower stem comes from close to the top of the plant and is longer than a few inches, it is not a nobile dendrobium. It is the warm growing type. The need to reduce fertilizer is to help initiate flowers in the fall and to give the plant a dormancy. But you already have the flower spike, so no change is needed. Keep it well watered while growing. Cynthia, Prescott, AZ

[jerrymeola]

In general it is good to reduce fertilizer on all plants when they are not growing actively.

In most parts of the country you have a short growing season. Feed and water heavily during those months and cut back in the fall and winter.

The thing to remember about most nobiles, Yamamoto types excepted, is that they are subject to monsoons. Hot, wet summers and cool, dry winters. First of all, never use fertilizer with a high nitrogen content as dendrobiums don't like a lot of nitrogen. Fertilize and water well from April or May to August. Stop all fertilizer in August and slowly start backing off the water. Sometime in November stop all water completely, and put the plant in a sunny but cold spot. Don't water the plant. If the canes start to shrivel, mist them. Remember in the wild this is their dry season. We are by nature nurturers, so it upsets us to withhold water for any creature, but this is what the plant has been conditioned to expect in order to bloom.

When little nubs start to appear up and down the canes, give baby sips of water only. Watering too much too soon can turn those nubs into keikis rather than blooms. Once the bloom opens, give baby sips only until the blooms are finished, then resume watering and fertilizing.

Yamamoto type nobiles do not need the severe drying out or chilling. I just keep this type of nobile slightly on the dry side for a couple of weeks and they bloom.