Shop Orchid Care OrchidTalk Orchid Forum Weather Station Links Nursery

Welcome to OrchidTalk Orchid Forums


The Friendliest Orchid Community on the Internet!


  •  » Learn to Repot your Orchids
  •  » Learn Orchid Care Tips and Secrets
  •  » Find the perfect Orchid for your Growing Environment
  •  » Chat with Orchid Growing Professionals

OrchidTalk - "Bringing People Together to Grow Orchids Better!"


Let us help you grow your Orchids better; Join our community today.


YES! I want to register an account for free right now!


Register or Login now to remove this advertisement.

Page 1 of 2 12 LastLast
Results 1 to 10 of 12
Like Tree12Likes

Rising and falling footcandles

This is a discussion on Rising and falling footcandles within the General Orchid Culture forums, part of the Orchid Culture category; I've read something a bit curious a while back. I forget where, but it said ...

Click here to increase the font size Click here to reduce the font size
  1. #1
    sand_tiger86's Avatar
    sand_tiger86 is offline Senior Member
    Real Name
    Kelly
    My Grow Area
    Porch/Patio.
    Favorite Orchid(s)
    Vandas and Catts
    Join Date
    Jul 2007
    Gender
    Male
    Location
    Texas
    Posts
    811

    Default Rising and falling footcandles

    I've read something a bit curious a while back. I forget where, but it said that when an orchid requires, for example, 3,500 fc of light, that means that is the highest the light exposure needs to get up to for the day - not necessarily what it needs to be all day. So basically, as the sun rises and falls, at some point in the day the orchid needs at least 3,500 fc (preferably a few hours of it). Is that right? I guess in my naivety, I just assumed that whatever light an orchid needs, whether it be 1,000 fc or 4,000 fc, it needs that light as long as the sun is shining.

  2. #2
    wetfeet101b's Avatar
    wetfeet101b is offline It's not dead! It's just permanently dormant.
    Real Name
    John
    My Grow Area
    Greenhouse
    Favorite Orchid(s)
    Cattleya, Cymbidium
    Join Date
    Jun 2007
    Location
    Riverside, CA
    Posts
    1,332
    Member's Country Flag

    Default

    Add to that the fact that the effective photo active radiation (PAR) that lands on the plants throughout the year vary significantly as the seasons change.

    When it comes to light, there are two main factors that need to be considered:
    1. Maximum solar energy that the plant can tolerate. In most cases it is not the intense illumination that kills orchids, but the intense UV rays that piggybacks along with it.
    2. Minimum PAR that the plant needs in order to perform photosynthesis - assuming the plant has access to water during the photoperiod.

    The light ratings given by vendors for orchids are based on their growing conditions and what works best for the plant based on their experience. So the rating they give could actually be anywhere between the upper and lower end of the plant's natural range.

    Barring special seasonal triggers, a plant receiving a consistent supply of light towards it's low-end limit could get the same results as a plant that gets fluctuating light supply that dips over and under it's natural range throughout the year.

    Think of this simplified formula (although it might be more art than science)
    Energy produced = (light intensity + water) x Photoperiod

    To compensate for low light intensity, increase the photoperiod.
    However, you can only extend the photoperiod so much before you end up depriving the plant of the dark phase that is also crucial for plant development.

    Simple, right?

  3. #3
    sand_tiger86's Avatar
    sand_tiger86 is offline Senior Member
    Real Name
    Kelly
    My Grow Area
    Porch/Patio.
    Favorite Orchid(s)
    Vandas and Catts
    Join Date
    Jul 2007
    Gender
    Male
    Location
    Texas
    Posts
    811

    Default

    So in idiot terms (for myself), a plant that receives well-above its maximum fc recommendation for a few hours but not quite at it's lower end for the rest of the day could do as well as a plant that only receives it's lower end of light recommendation for longer periods of time?

    *head spinning*

    I'm only confused because I've read so many different things. I guess as someone else told me earlier, I fuss over these plants too much. I probably just need to let nature take its course instead of being so anal about every aspect of them!

  4. #4
    wetfeet101b's Avatar
    wetfeet101b is offline It's not dead! It's just permanently dormant.
    Real Name
    John
    My Grow Area
    Greenhouse
    Favorite Orchid(s)
    Cattleya, Cymbidium
    Join Date
    Jun 2007
    Location
    Riverside, CA
    Posts
    1,332
    Member's Country Flag

    Default

    Quote Originally Posted by sand_tiger86 View Post
    a plant that receives well-above its maximum fc recommendation for a few hours but not quite at it's lower end for the rest of the day could do as well as a plant that only receives it's lower end of light recommendation for longer periods of time?
    Yes*

    * Assuming sunburn and dehydration does not occur on the former example and sufficient dark phase is provided to the latter example.

  5. #5
    wetfeet101b's Avatar
    wetfeet101b is offline It's not dead! It's just permanently dormant.
    Real Name
    John
    My Grow Area
    Greenhouse
    Favorite Orchid(s)
    Cattleya, Cymbidium
    Join Date
    Jun 2007
    Location
    Riverside, CA
    Posts
    1,332
    Member's Country Flag

    Default

    Quote Originally Posted by sand_tiger86 View Post
    I'm only confused because I've read so many different things. I guess as someone else told me earlier, I fuss over these plants too much. I probably just need to let nature take its course instead of being so anal about every aspect of them!
    No two plants will ever behave the same. You can set up two identical species in two identical conditions and chances are they will turn out different from each other.
    So take every grower's word with a grain of salt. Unless your plants will be sitting right next to their plants, your results will be guaranteed to be different to a certain degree.

  6. #6
    Sirena is offline Junior Member
    My Grow Area
    Windowsill
    Join Date
    Jun 2012
    Gender
    Female
    Location
    Massachusetts
    Posts
    5
    Member's Country Flag

    Default

    I've been focused on making sure that my plant gets the right amount of light and water. It never occured to me that it would need a dark phase. How much dark phase would an orchid need?

  7. #7
    lijun's Avatar
    lijun is offline curious
    Real Name
    lijun
    My Grow Area
    Porch/Patio.
    Favorite Orchid(s)
    exploring and getting greedy
    Join Date
    May 2014
    Gender
    Female
    Location
    north sumatra, indonesia
    Posts
    394
    Member's Country Flag

    Default

    Quote Originally Posted by Sirena View Post
    I've been focused on making sure that my plant gets the right amount of light and water. It never occured to me that it would need a dark phase. How much dark phase would an orchid need?
    Correct me if i'm wrong , from my understanding, at least about 8 to 10 hours daily.

  8. #8
    Halloamey's Avatar
    Halloamey is offline Senior Member
    Real Name
    Amey Bhide
    My Grow Area
    Greenhouse
    Favorite Orchid(s)
    Cattleya alliance
    Join Date
    Jul 2009
    Gender
    Male
    Location
    Pune, India
    Posts
    5,363
    Member's Country Flag

    Default

    Another important factor which has been forgotten here is the temperature which usually goes hand in hand with brighter light. A few hours with higher than recommended light would only be any good if the temperature is maintained at the cooler end, if the temp. increase with light it will result in scorching. And secondly few hours with more light is not the same as may more hours with less light. A particular threshold of light energy is necessary for the excitation of the electrons and the working of the photosystem. Imagine it like a mechanical process for eg. 4 men need 1 minute to push open a heavy iron gate, any less men and they will not be able to push open the gate, so 2 men even if they pushed for 2 minutes will not be able to open the gate.

  9. #9
    raybark's Avatar
    raybark is offline Senior Member
    Real Name
    Ray Barkalow
    My Grow Area
    Under Lights
    Join Date
    Oct 2012
    Location
    Oak Island NC
    Posts
    1,268

    Default

    I am likely the person who espoused the maximum comment referred-to in the first post (as I've never heard anyone else state that....).

    Adding to Halloamey's excellent analogy, some time at higher light levels plus some time at lower light levels, indeed, does not equal all time at correct light levels. Not only is there the energy threshold issue, and the potential to negatively affect the chemical reactions that take place within the leaf by overheating, but there is the fact that the reaction rates are not linear with light intensity.

    There are several different, but connected chemical processes involved, and they likely don't all happen at the same rate. You may push chlorophyll more with higher light, but that doesn't mean that the other associated reactions are going to keep up. And who's to say what "messing with" the relationship between those reactions can do?

    A practical example is the lowly phalaenopsis: they do really well in the lower-light environment of many households. Transition them into an environment with higher light levels, and they can actually bloom less!

  10. #10
    lijun's Avatar
    lijun is offline curious
    Real Name
    lijun
    My Grow Area
    Porch/Patio.
    Favorite Orchid(s)
    exploring and getting greedy
    Join Date
    May 2014
    Gender
    Female
    Location
    north sumatra, indonesia
    Posts
    394
    Member's Country Flag

    Default

    thing is,... i got this don't know how big/small this problem is,.. i did read about total darkness is also essential for orchids, other than lights. if it has similar function like how human body produce melatonin in darkness, or not,.. i'm not that sure, i haven't gone deep on this particular topic,..
    but i don't have that darkness at night in my area, live in one of the main road here, many lights at night...

Page 1 of 2 12 LastLast

Similar Threads

  1. Dendrobium buds falling off
    By ransikaal in forum General Orchid Culture
    Replies: 3
    Last Post: February 4th, 2012, 08:34 PM
  2. FootCandles/Lights
    By Raver in forum Semi Hydro / Lights / Greenhouses / Accessories
    Replies: 8
    Last Post: May 26th, 2010, 02:15 PM
  3. Phrag. Jason Fischer 'Phoenix Rising' FCC/AOS
    By lienluu in forum Paphiopedilum, Phragmipedium, Cypripedium IN BLOOM
    Replies: 8
    Last Post: February 26th, 2008, 05:05 PM
  4. Footcandles....
    By mtequine in forum Semi Hydro / Lights / Greenhouses / Accessories
    Replies: 6
    Last Post: February 11th, 2007, 12:09 PM
  5. Buds falling off
    By MiddleAgesMan in forum Orchid Ailments / The Compost Pile
    Replies: 6
    Last Post: August 12th, 2005, 01:47 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
OrchidTalk --An Orchid Growers Discussion Forum brought to you by River Valley Orchidworks. A World Community where orchid beginners and experts talk about orchids and share tips on their care, cultivation, and propagation.