Orchids under lights

[gardenguysorchids]

I am growing my 100 plus orchids in my basement underlights. I have catts, phals, paphs, dens, and oncids. Currently my lights (flourescents) come on at 7:00 AM and go off at 11:00 PM. I have read several contradictory articles on the amount of light needed. Some state that from December -February the amount of light should be lowered to 12 to 14 hours. Others state that the light should remain at 16 hours. I would deeply appreciate anyone who could give me a definative answer on this. Before moving my orchids to the basement I was a window sill grower. The area I have my orchids in also has a large double glass door that faces directly East . The temp stays at 60 to 65 degrees. Thank You, Bill

[orchidlady]

Not sure there is a definitive answer. I grow mostly Phals and Paphs under lights and have since 1989. As far as I can recall, I have never altered light with the seasons and the plants do just fine. I run lights about 16 hours a day and also have some natural light from a sliding glass door. I suppose it is possible some plants may be more finicky about the amount of light, but I don't know of any specifics in that regard.

Susan

[cindiras]

Because my birds are caged in the basement along with my plants, my lights are set for 14 hours for the sake of the birds. They seem to be doing fine. I have some Dens blooming now, Catts, and oncids blooming and a cymbidium with buds.

[stefpix]

near the equator anyways the lenght of day/nights is more or less costant throughout the year.
Poinsettias may be finnicky about this... But equatorial orchids probably have 12 hours of daylight and 12 hours of darkness...

[Paph]

I agree with Stefpix; I often read too that we should have to increase the light in late fall & winter. I have an orchidarium with 6 lights: 3 of my lights turn on at 7:00 AM and go off at 19:00 PM and 3 of them turn on between 11,00 AM and 16,00 PM.

[smartie2000]

If you are growing only underlights, you are decreasing the daylength in the winter time. This is because you are stimulating the natural seasonal changes.
but this is not so important if you only have plants that don't rely on seasons (eg complex hybrids). It's more important for blooming on some species that rely on the daylength as seasonal cues for blooming or dormancy.

[Lambert]

It's more important for blooming on some species that rely on the daylength as seasonal cues for blooming or dormancy.

I completely agree.
Some Catts, for instance, are photoperiodic (day-length sensitive), some get their blooming cues when days get shorter and others when days get longer.

Here is the most often suggested number of hours of light per day following the seasonal changes

11.5 hours of light in December,
12 hours in mid-January,
13 hours in February,
14 hours in March through August,
13 hours in September,
12 hours in October,
and 11.5 in November.

[stefpix]

But if a plant comes from the tropics/ euquator the change in day / night length is rather negligible and also there are no 4 seasons but more of a wet and a dry season.

a complex hybrid still could behave like one of the parents. Phenotype and genotype are not the same.
you could make a hybrid between a cool and a hot growing and the next generation does not need to be intermediate.
it could still be warm growing or cool growing.
Introduction to genetics - Wikipedia, the free encyclopedia

it is more likely that a plant adapts to the environment rather than averaging teh phenotypes by mixing genes.

plants survive periods of draught or unpredictable weather.

I think a small plant that grows in a home will adapt to that environment to a certain extent.

if some orchids grow different roots for different media. bark , sphagnum, water culture, SH. Why could not they adapt to somehow different conditions?

So anyway - Indoor lights do not have the same intensity and the same spectrum of the sun. Otherwise the grower would get sunburned by spending a few hours in the greenhouse next to the lights. I am sure on some hill in Brasil most people that have no tan do have to wear sunscreen.
So maybe you need more hours of artificial light than hours of sun.
I am just saying that there must be a range of adaptability

[orchidlady]

I would agree with Stefpix. My understanding about orchids in general is that environmental conditions such as moisture/water and temperature are more important in initiating flowering than photoperiod.

Susan