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Post by dToad on Dec 12, 2011 3:22:51 GMT -5
Most of the guidance for light and temperature needed to grow VFTs is anecdotal. The best advice is the recommendation to match the natural conditions VFTs evolved in, yet I've been unable to find that on any carnivorous plant site. Here it is. I've gathered the data from various sites, and tried to put it into a form we can use. Knowing the solar power, we now need to determine a relationship between that, and luminous intensity. Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, which includes infrared, visible, and ultraviolet light. Approximately 35% of the radiant flux is within the visible spectrum. The peak luminous intensity is therefore 93 * 0.35 * Maximum Solar Power. It varies from about 19,500 lux in Dec to 40,000 lux in Jun. A more useful measurement for us is lumens / sq ft. There are 10.76 sq ft in a square meter. The peak luminous intensity is then about 1800 - 3700 lumens/sq ft. A Little LightSimply put, we perceive colour of an object by the light that it reflects. We see an object as black when it absorbs the entire visible spectrum, and white when reflects all visible light. We perceive other colours when an object reflects only part of the visible spectrum. The colour we see corresponds to our perception of the reflected wavelengths of light. Our eyes are usually tricked into perceiving colour by artificial lights supplying only a few wavelengths of light. The colour of some objects then appears 'off' under that lighting as those objects absorb some of the wavelengths, changing the mix. The foliage of most plants appears green. This does not mean that only the green wavelengths are reflected, but that we perceive the sum of all of the reflected wavelengths as the colour green. Some of the absorbed light is used by the chloroplast and photosynthetic membranes to produce compounds promoting plant growth. You'll note in the diagram above that chlorophyll absorbs light mainly in red and blue areas of the visible spectrum to produce the compounds required for plant growth. A plant needs some wavelengths of light for growth. We need the remainder of the visible spectrum to appreciate the plant's full splendor. References:The Weather Network - www.theweathernetwork.com/statistics/C02389/ussc0531Online Sunrise / Sunset Calculator - www.sci.fi/~benefon/sol.htmlWikipedea - en.wikipedia.org/wiki/SunlightDigikey (color of light) - www.digikey.com/us/en/techzone/lighting/resources/articles/understanding-the-color-white.htmlFarabee (photosynthesis) - www.emc.maricopa.edu/faculty/farabee/BIOBK/BiobookPS.html
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Post by dvg on Dec 12, 2011 7:01:07 GMT -5
That's a nice piece of research that's you've managed to compile and post here dToad.
I like the way you think.
This is something that all of us should look into when we are setting up to grow a plant we may be unsure of or are already having issues with.
In addition to the type of information you have provided above, knowledge of rainfall/precipitation and soil composition in a specific plant's native habitat, if it is known, can also help to further pin down the cultivation conditions that we will attempt to approximately mimic.
In other words, we would all be better serviced if we were willing to take some time and do our homework first, with regards to selective plant habitat.
And that is one important reason why plant locale information is so very useful.
Thanks for taking the time and effort to do the work and share it here.
dvg
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Post by dToad on Dec 12, 2011 10:19:55 GMT -5
Thanks.
I found that soil mix recipes were readily available. How to build up a successful bog was only slightly harder to find than the soil mix. The Weather Network also has gross percipitation statistics for those who are interested. There are other sites that have detailed weather data including histories of wind speeds and rainfall amounts. Folks may have to search seemingly unrelated websites such as those for home insulation to stumble upon them.
I'm going to carry it a bit further by covering the visible solar spectrum, and that used by plants for photosynthesis.
I'll add a seperate reply showing how to mix and match T5s to best replicate what plants need. I'll also show how to use an outdoor/indoor method to closely match their natural environment with minimal expense.
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Post by lloyd on Dec 12, 2011 12:19:08 GMT -5
Very useful information. It makes sense now why my VFT's do better in the fall. Toronto summer min temps are too high for VFT's.
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Post by Apoplast on Dec 12, 2011 23:00:56 GMT -5
dToad - Solid data you have compiled. If you don't mind my asking, I am curious why you chose Camden, SC though as it seems to be slightly outside of the native range? Wouldn't Wilmington, NC be more appropriate if you are looking to replicate the climate of the native range?
Speaking of native ranges, it can't be assumed that the climate in a species native range is optimal for the growth of the species. The reason is because the natural ranges of species are often restricted by more than their own physiological tolerances.
In cases like that of VFT, where the native range has likely been much larger in the past, the climate of the remnant portion of the range could potentially be marginal for the species for a number of factors. Certainly, VFT has naturalized in different places, e.g. Florida panhandle and New Jersey, suggesting, at the very least, VFT has much wider climate tolerances than exhibited by its current native range.
I really don't mean to be a downer here. It is just that as much as this approach is likely to yield good results, it is also important to realize the potential limitations as well.
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Post by dToad on Dec 13, 2011 4:35:57 GMT -5
Choosing statistics for Wilmington, NC brings up Darlington SC.
I picked Camden as it is a city relatively close to where VFTs still grow in the wild, and that has the weather data available. Its is also within the range shown on many maps.
I know that the range has shrunk over the years, but this is an area close to where they still live. With the anecdotal evidence for 'ideal growing conditions' prevailing on many sites devoted to VFTs, I wanted a reference to compare them. This helps weed out the trash.
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Post by Apoplast on Dec 13, 2011 9:13:37 GMT -5
Hi dToad - If you are looking for information on Wilmington, NC, there is a national weather service office there, so NOAA has good data for that city: www.erh.noaa.gov/ilm/cliplot/Looking at several individual years will provide an idea of the variability the plants will experience in their native habitats too. For example, 2011 saw temperatures range from about -8C to about 38C each for brief periods, but 2008 was more moderate. And as Lloyd pointed out nighttime temperatures do seem to fall pretty dramatically throughout the year. Interesting that Camden, SC has VFTs. I didn't realize they were found that far inland in South Carolina. But then again I was using the USDA occurrence data which is notoriously bad for some species, so I don't know if this page is a good representation of their range in SC or not: plants.usda.gov/java/county?state_name=South%20Carolina&statefips=45&symbol=DIMU4 It really was great work putting everything together for people in an easily referable, tabular form. Replicating the conditions from a plant's native range is a proven way to get plants to survive in captivity. I'll bet people will be referencing this page a lot.
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Post by dToad on Dec 13, 2011 11:23:35 GMT -5
The figures from 'The Weather Network' are a 30 year average from 1961 to 1990 for each month.
For my own use, I thought that daily temps would vary about +/- 5 from the averages, which is close to what you found.
The city I orignally tried for was Loris, SC. The statistics for that city brought up Camden, so I went with the flow :-)
BTW, Wilimington,NC brings up Darlington SC's statistics.
The photoperiod and solar power figures are accurate all along the specified latitude, whether in the Carolinas or California. Variance will be noted in sunrise/sunset times.
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Post by dToad on Dec 15, 2011 7:50:12 GMT -5
I've added a little light to the original post in this thread.
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Post by lloyd on Dec 15, 2011 13:18:09 GMT -5
I read your light comments above. I've followed the "light debate" on this forum and looked around the net, too. I'm falling into the group that thinks that the whole spectrum (or at least more than the Chlorophyll A & B absorption maxima) is necessary for at least some plants, some of the time. For instance my LED's are tuned to the Chloro. maxima and some plants do very well (like utrics, D. aliciae, P. emarginata, tuberous dew, etc.) but some do not do well and remain stunted, growly really slowly (some of the pygmy dews, D. hamiltonii, P. ehlersiae, etc.). I don't think it's the actual light strength because the LED's are blinding and on 16 hours/day. So I think we have a lot to learn about wavelength requirements which may vary significantly for some plants, some of the time.
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Post by dToad on Dec 15, 2011 18:20:38 GMT -5
I tend to agree with you Lloyd.
One of my references (Farabee) contains a diagram of the 'action spectrum' for elodea, a common aquarium plant used in photosynthesis lab experiments. The action spectrum is far greater than that of the chlorophyll absorbtion spectrum.
I personally think that different species use different light spectra for growth. A spectral analysis of the light reflected from the various species would probably be a far better indication of their requirements.
My approach has been to request the spectral output for several lamps that are available. I'll mix and match the lamps so the total output is as close to the visible solar specturm as possible. While I wait for the manufacturer's data, I'm using a mix of various color temperatures. Perhaps, at some later date, I'll run controlled experiments with a few species and cultivars.
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