Skip dormiancy with artificial light and temperature

[estación seca]

Most epiphytic orchids come from near the equator, where there is not a lot of day length difference through the year. You might have better results, and save money on electricity, with a 12-hour day in summer and a 10-hour day in winter. A 16-hour day might inhibit some orchids from flowering.

[camille1585]

With your Phal example, by giving optimal light and photoperiod you are simply allowing the plant to grow to its fullest potential. For Phals, as long as you aren't growing too hot year round (flowering is inhibited if it's too hot, which is something commercial growers exploit to time flowering), giving optimal light will only improve flowering.

That is quite different from plants which have a true dormancy. It's likely that if you gave them the optimal conditions from their growing season year around as opposed to seasonally, you wouldn't get any blooms. For instance, it's well known for temperate plants needing a cold winter (brassicas for one) that the cold dormancy affects all sorts of genes which then 'unlock' the plants ability to flower once the conditions become favorable. This is also why climate change is getting problematic, for instance strawberries need to acculumate between 100 and 800 chilling hours where the temperature is between 0 and 7°C in order to flower.

I would assume that this would be true for plants needing a dry dormancy too. One of the tropical plant species I've been researching at work (which I can't name due to confidentiality reasons) needs a dry period in order to flower later on, once the rains arrive. I have very clearly showed that even if all other growing conditions are optimal, the plants will absolutely NOT flower until that moisture deficit requirement is met.

[Subrosa]

Originally Posted by DavTom

Hello,

Sorry if this topic is already addressed somewhere.

I am wondering if and how much orchids that go dormient in nature can be forced to grow/bloom continuosly via artificial light and the right temperature. As we all know, orchids are slow growers compared to most plants...so, avoiding the winter rest would be handy, if feasible...

Anyone has had direct expirience on that, especially with orchids that are known to go "very" dormient in nature? For instance, Phals do NOT require much dormiancy...

Some plants, like the Venus Fly Trap, will simply die off after a few years without winter rest.

Thanks in advance.

Cheers,
Dav

If you artificially alter the photo period and temperature, you're not skipping dormancy.

---------- Post added at 05:31 AM ---------- Previous post was at 05:25 AM ----------

The bulk of my orchids are strongly seasonal. Those that can can handle winters here are in the ground, but I also grow a few from areas still considered temperate,, but not as cold as here. They winter in a cool basement under 8 hours of daylight, to simulate winter.

[Aleksa91]

I have a dilemma which kind of falls under this thread.

I have recently set up a terrarium with a bunch of miniatures, most of which do not need a distinct rest period. However, I got a few Dendrobiums (unicum, jenkinsii, margaritaceum), rupicolous Laelias (itambana, millerii, alaorii) and Sophronitis (riograndensis, wittigiana) which apparently benefit from dry-ish and cool-ish winter rest.

I live in Germany, so we are now well into fall. Interestingly, D. jenkinsii and D. margaritaceum show signs of dormancy (no growth) while others are still actively growing (lots of new roots and shoots). I moved the first two to the other, colder room.

My dilemma is: should I rest the others or not? I am tempted to just observe them and wait for the growth to stop before reducing watering/temps, rather than imposing rest period in the middle of the growth phase. They may be ready for a month or two of rest in mid-winter or at the end of it, considering that the shoots are just forming now. I've also been told that the rest period is not as essential as it is typically considered...

[Clawhammer]

Originally Posted by DavTom

Hi all, many thanks for all your feedback.

But, has anyone of you tried to hit orchids that are well know to go dormant in nature with optimal light/ temperature etc... 24/7 for at least one year?

The feedback received so far seems more based on common sense and literature rarher than on personal experience. I trust real experience more...for how many decades people believed that low N and hight P was required to promote flowering?...

Ok, let me share my personal expirience. I have hit Phals with optimal light/temperature 24/7 for 1 year. They grew and bloomed crazy with so many lasting flowers thar illuminating the leaves with spor lights became almost impossible as the flower were shading everything. Following year I did not use artificial lights and growth/blooming was much reduced Still nice, but not comparable at all.

With other orchids like Bulbp, Cattl and Dendr it did not work so good. Cattl and Dendrob doing well, but nothing exceptional, and Bulbp not flowering much...

Cheers,
Dav

With all due respect, people have been growing orchids for 100s of years. Something this fundamental is not just conventional wisdom, it has been tested before. Almost all orchid growers have plants they struggle to bloom and only have success once they make a change that enables their natural blooming triggers. No one is adding dormancy complexity to their culture for fun.

[Aleksa91]

Originally Posted by Clawhammer

With all due respect, people have been growing orchids for 100s of years. Something this fundamental is not just conventional wisdom, it has been tested before. Almost all orchid growers have plants they struggle to bloom and only have success once they make a change that enables their natural blooming triggers. No one is adding dormancy complexity to their culture for fun.

I agree, that's why I wonder...

[Roberta]

A thought on those Dendrobiums especially... Maybe must move them out of the terrarium. They'll be drier, and probably cooler As for ones still actively growing, maybe wait a month or so, everything doesn't slow down at the same time.

I grow outside so it is really different situation of course. I don't move my deciduous Dens, they get watered and rained on but they do get cold. I do try to protect the rupiculous Laelias from rain but water them a bit. ("Dry" at my house is a lot drier than in the tropics)