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  • LED Grow Lights 2020 - White LEDs; Household LED Bulbs and LED Tubes?

    Two decades of Academic Research clearly indicates that spectrum and intensity dictate the growth and shape (morphology) of a plant, with broad / wide spectrum resulting in healthiest growth and production. The "Limiting Factor" initially with White LEDs (WLEDs) as Sole Sourse Lights (SSL) was Low Electrical Efficiency, which was overcome with the advent of the current generation of WLEDs that produce over 100 Lumens per Watt (L/W). Following are two (2) lengthy but informative interviews with Academic Agricultural Lighting Researchers and this article; https://www.migrolight.com/best-grow-light-spectrum/





    Household LED Bulbs (UL and or DLC Listed) can provide adequate PAR and EPAR / PBAR (light) contrary to "Perpetuated Grow Light Misinformation / Myths". 2700K and 3000K LED bulbs rated 80 or more CRI can provide better PAR spectrum than Red / Blue LEDs and HPS, the Agricultural Industy incumbent grow light, while 4000K and 5000k LEDs can provide better spectrum than Metal Halide and Fluorescent. Standard 100 Watt Equivalent LED light bulbs labeled as 1600 Lumens per 15 watts (Actual Measured Output) produces over 1700 Lumens with the opaque globes removed, resulting in at least 1.8 PPF efficiency and 4 foot T8 LED tubes labeled as 2200 Lumens per 17 watts are at least 1.9 PPF efficiency (1000 Lumens = or ~ 15 PPF).
    ...
    https://www.biorxiv.org/content/bior...15095.full.pdfClick image for larger version  Name:	image_79803.png Views:	12 Size:	61.9 KB ID:	680826
    Light Source PPF (Efficiency)
    1000W DE HPS 1.7
    400W HPS 1.5
    400W MH HID 1.4
    315W CMH 1.5
    Fluorescent 0.9
    ...
    WLEDs (100 L/W) 1.5
    WLEDs (120 L/W) 1.8
    WLEDs (130 L/W) 1.9
    ...
    ...
    References:
    https://www.biorxiv.org/content/bior...15095.full.pdf
    https://www.biorxiv.org/content/bior...89280.full.pdf

    https://www.ourfigs.com/forum/figs-h...r-fig-cuttings
    https://www.ourfigs.com/forum/figs-h...504#post467504

    https://journals.plos.org/plosone/ar...l.pone.0163121
    https://www.valoya.com/spectra/
    https://www.migrolight.com/best-grow-light-spectrum/

    Commercial White LED Grow Lights... 2020
    https://images.homedepot-static.com/...b830887103.pdf
    https://images.homedepot-static.com/...00bfc96eab.pdf
    Last edited by AscPete; 12-22-2019, 07:35 PM. Reason: added graphics, links, corrections and edited table...
    Pete R - Hudson Valley, NY - zone 5b

  • #2
    So... I don’t need LED grow lights just several LED lights
    Zone 5 Omaha. WL - Michurinska green

    Comment


    • #3
      In the white spectrum
      Zone 5 Omaha. WL - Michurinska green

      Comment


      • AscPete
        AscPete commented
        Editing a comment
        Yes...
        And it also depends on Application; seedlings, cuttings, etc and Footprint; growing area

      • Alexoo9
        Alexoo9 commented
        Editing a comment
        Man... every time I try and get a grip on this my head starts hurting. I just wish there was an easy plug and play system for all my lighting needs. Thanks for the research and the post!

    • #4
      Alexoo9 Don't over-think it. I have read a lot of AscPete's stuff, and I am starting to catch the lingo (barely) but you don't have to get it all to make something functional. What I found from his data and my experience is if you can get 12000 lumens via white LEDs in the 3000k to 5000k ranges spread out over your average storage shelf that measures about 15 inches by 36 inches, you will have plenty of light.
      For me this means eight 100 watt LED bulbs measuring 1500 to 1600 lumens each. I get half warm white (3000k), half bright white/daylight (5000k most common available).

      Works perfectly.
      Zone 8b, College Station, TX
      Wish List: Maltese Beauty, CLBC.

      Comment


      • BrandonP
        BrandonP commented
        Editing a comment
        ammo1a1970 Like AscPete said, my bulbs are about 15W (100W equivalents). Sounds like a good grow light you got there. Possibly more efficient than standard LED bulb set ups and likely a lower profile. Just more expensive up front cost and less customizable in terms of footprint. Definitely a time saver to go with something pre-made.

      • ammo1a1970
        ammo1a1970 commented
        Editing a comment
        Yes thats the light. I bought 11 of them. All my plants are growing better than expected. I replaced my 15 watt led florescent replacement bulbs with these. They work much better.

      • AscPete
        AscPete commented
        Editing a comment
        ammo1a1970 ,

        Thanks for the reply.

        The Samsung diodes are the current Generation of High performance White LEDs... They are similar in performance to the current Generation of Household White LEDs, the “Real” major differences are Power Supplies, Heatsinks and Form Factor.

        If I needed year round Grow Lights they would possibly be my Choice, but for seasonal growing the 12 bulb string light with $1.00 / 15 Watt / 1600 Lumens LED Bulbs and a Dimmer provides more light at 1/4 the purchase cost of the HLGs, along with being customizable for area and spectrum.

    • #5
      I am using hi bay led lights 200 watt and 240 watt they are better then 1000 watt hps. lights . working well for me. 3 lights light up a 14 x 30 foot area.they cost about 100. bucks each but really light up a large area with not much heat.

      Comment


      • AscPete
        AscPete commented
        Editing a comment
        I agree that the new DLC Listed high bay LEDs are better, but they their PAR output at ~ 140 Lumens per Watt is ~ 2.1 PPF (140 x 0.015 PAR Conversion Factor) while newer high efficiency 1000W DE HPS fixtures are ~ 1.7 PPF.

        The total PAR output of the HPS fixture would be greater than the LEDs, but the higher CCT (K) and higher CRI (Ra) values make the LEDs appear brighter to our "Human Eyes".

    • #6
      What matters for plants is actual Watts (not equivalent Watts, and not lumens), along with appropriate color temperature, and high color temperature accuracy.

      I've yet to see an LED system that can meet the requirements for fruit trees.
      ​​​​​​
      Fruit crazed in Vista CA. http://tangentvectors.org

      Comment


      • ginamcd
        ginamcd commented
        Editing a comment
        Please clarify -- For fruit trees for fruit production, or to keep fruit trees green and "happy" indoors until they can be moved outside into sunlight for fruiting?

      • fighobo-1
        fighobo-1 commented
        Editing a comment
        try a 200 watt hibay led you may change your mind I did. I have 1000 watt hps lights side by side to the led lights the figs under the leds are growing just as good if not better and they set figs . and the power bill is 100. a month the hps. lights run over a 1000. a month . I am shutting the hps. lights off as soon as it warms up.

    • #7
      Alexoo9 I agree with BrandonP , "Don't over-think it"...
      There are only a few formulas with a few fixed "factors" that apply to all indoor grow lights.

      https://www.ourfigs.com/forum/figs-h...r-fig-cuttings
      Those recommendations for stem cutting propagation equate to;
      (Stage #1 / pre-rooting) 100 to 200 umol-m2-s (PPFD) = ~ 6,000 to 12,000 Lux (@5000K LED)
      (Stage #2 / rooted)... 200 to 400 umol-m2-s (PPFD) = ~ 12,000 to 28,000 Lux (@5000K LED)
      For example the 15 inches by 36 inches shelf is 3.75 sq ft or ~ 0.375 sq m , the 12,000 Lumens (multiplied by 0.015 conversion factor) is ~ 180 PPF (umol/s) and the calculated coverage is 180 / 0.375 = 480 PPFD (umol / m2 / s)

      On-going Published Scientific and Academic Research has shown that the most efficient Full Cycle - Sole Source Light Spectrum (for Plants not Energy usage) is approximately;

      - Blue (400 - 499 nm) = ~ 10% - 20%** (25% Max)
      - Green (500 - 599 nm) = ~ 20% (25% Max, B:G ratio 0.5 - 1.0)
      - Red (600 - 699 nm) = ~ 60% (R:B ratio > 2.0)
      - FarRed (700 - 780 nm) = ~ 8% (R:Fr ratio > 1.0)

      ** Percentage Blue selected for 10% - 20%, Blue:Green Ratio, Red:Blue Ratio and Red:Far Red Ratio are the most important parameters of a grow light spectrum after adequate PPFD / intensity...

      https://helda.helsinki.fi/bitstream/...pdf?sequence=1
      HPS: B-6%, G-45%, R-42%, FR-10%, PAR-n/a, CCT-2000, CRI-60
      CWF Fluorescent; B-35%, G-24%, R-36%, FR-4%, PAR-n/a, CCT-6200, CRI-80

      https://www.valoya.com/spectra/
      AP673L; B-12%, G-19%, R-61%, FR-8%, PAR-92%, CCT-2000, CRI-60
      NS2 ; B-20%, G-39%, R-35%, FR-5%, PAR-94%, CCT-4800, CRI-90

      https://hubbellcdn.com/brochure/hil_0401_cgs_ref_16.pdf
      3000K PC LED; B-11%, G-41%, R-44%, FR-4%, PAR-96%, CCT-3000, CRI-80
      5000K PC LED; B-22%, G-46%, R-30%, FR-2%, PAR-98%, CCT-5000, CRI-80

      Valoya AP673 and NS1/NS2 "Stock" fixed spectrums appears to be light recipes that can be closely simulated with Household LEDs. 3000K LED bulbs could also be supplemented with Blue and Red LEDs to simulate their AP67, if needed. The documented research shows that When the appropriate Blue wavelength content is chosen for the crop plants Valoya LED lights have equivalent or superior growth to the incumbent Flourescent and or HPS lights.
      Last edited by AscPete; 12-23-2019, 01:08 AM. Reason: added link...
      Pete R - Hudson Valley, NY - zone 5b

      Comment


      • #8
        This is perfect timing as I've been trying to make sense of all the great lighting advice on this forum this weekend before I checked out the LED bulbs at the local dollar stores, L0wes, and [email protected] today. These were the lowest priced bulbs.

        My lighting setup would simply exist to help 10 rooted fig cuttings grow healthy until spring. I don't plan on expanding this setup.

        Any suggestions on which ones to pick and the quantity of each?



        2700K - 100W Equivalent - 16W (Philips)
        $4.00 Canadian ([email protected])

        Click image for larger version  Name:	2700K_100W_back-Philips.JPG Views:	4 Size:	1,009.0 KB ID:	680960



        2700K - 100W Equivalent - 15W
        $4.00 Canadian ([email protected])

        Click image for larger version  Name:	2700K_100W_Dollarama.JPG Views:	4 Size:	1.45 MB ID:	680962


        3000K - 60W Equivalent - 8W
        $1.25 Canadian (DollarTr33)

        Click image for larger version  Name:	3000K_60W_dollartree.JPG Views:	4 Size:	951.6 KB ID:	680959


        5000K - 100W Equivalent - 15W
        $4.00 Canadian ([email protected])

        Click image for larger version  Name:	5000K_100W_Doolarama.JPG Views:	4 Size:	1.39 MB ID:	680963

        Thanks!
        Attached Files
        Last edited by rambaldi; 12-23-2019, 01:22 AM.
        Southern Vancouver Island, British Columbia, Canada

        Comment


        • AscPete
          AscPete commented
          Editing a comment
          I am currently using (purchasing) Sunbeam 3000K / 100 WEq / 1600 Lumens / 14.5 Watt LED bulbs at Dollar Tree for $0.50 each (2 for $1.00)... I've also used those 60W Dollar tree bulbs, but have transitioned to the Dimmable 100 Watters with an inline (actual 150 watt for multiple bulbs) Dimmer for less / low intensity applications. 2700K will work but have less than 10% Blue wavelengths which could lead to larger leaves and stretching of stems. A 1:1 ratio of 2700K:5000K is 3800K and a 2:1 ratio is 3400K, both ratios should provide adequate spectrum for growth along with all 5000K which would provide for slower / smaller growth.

          BTW, quantity depends on the total covered area (in sq m), you will need approximately 400 PPFD (27,000 Lux) For example; If you have an area of 0.5 sq m with a required 400 PPFD the formula would be 400 x 0.5 = 200 PPF fixture requirement (Required Intensity in PPFD multiplied by area in Sq M equals Light Required)...

          200 PPF is equivalent to 13,500 Lumens (3000K - 5000K LED) or 9 - 10 100 Watt Equivalent LED Bulbs, a 12 bulb Outdoor String Light could be used as the "Fixture" (usually $20.00) ;https://www.harborfreight.com/home-o...hts-63483.html
          Last edited by AscPete; 12-23-2019, 04:39 AM. Reason: Added info and BTW...

        • rambaldi
          rambaldi commented
          Editing a comment
          Thank you very much AscPete for your continued guidance on this important topic!

        • AscPete
          AscPete commented
          Editing a comment
          rambaldi ,
          You're welcome.

      • #9
        Here's a simple chart for sizing a Hobby Grow Light Steps #1 and #2 will work for any type of Grow Light...


        Click image for larger version  Name:	diy led grow light sizing table.png Views:	24 Size:	21.0 KB ID:	681328

        Also;

        Click image for larger version  Name:	IMG_2031.jpg Views:	25 Size:	95.0 KB ID:	681329

        For any "White Light" Source; HPS, MH HID, CMH / LEC, White LEDs, Fluorescent, etc,
        An inexpensive Lux Meter that costs under $20.00 can be used to measure and adjust the light intensity / height


        https://www.apogeeinstruments.com/co...n-ppfd-to-lux/

        White Light Lux Conversion Factors:

        0.0185 = Sunlight
        0.0135 = Cool White Fluorescent (& CFL)
        0.0122 = Mogul Base HPS Lamps
        0.0130 = Dual-Ended DEHPS: ePapillion 1000 W
        0.0141 = Metal Halide
        0.0154 = CMH / LEC (CMH942): 4200 K CCT
        0.0170 = CMH / LEC (CMH930-Agro): 3100 K CCT

        Multiply the Lux by the conversion factor to get PPFD or Lumens by conversion factor to get PPF.
        For example, full sunlight is 108,000 Lux or 2000 µmol m-2 s-1 (108,000 ∗ 0.0185).
        Last edited by AscPete; 12-24-2019, 08:28 AM. Reason: Added "Apogee White Light Conversion Factors" and link...
        Pete R - Hudson Valley, NY - zone 5b

        Comment


        • #10
          Very helpful and timely as I plan lighting for another grow shelf! Thanks!
          Maryland - 7a

          Comment


          • AscPete
            AscPete commented
            Editing a comment
            You're welcome.

            BTW, if your shelves are 4 ft wide T8 led bulbs in T8 shoplight fixtures may be an option, each pair of T8 LED tubes at 2200 Lumens each are outputting approximately 66 PPF (total).
            Last edited by AscPete; 12-24-2019, 03:21 PM. Reason: Added BTW with T8 LED recommendation...

        • #11

          Notes for this video;
          T5 Bulb is 6800K, 80 Lumens/Watt
          CFL Bulb is 4550K, 44 Lumens/Watt
          SK MLH is 5000K, 95 Lumens/Watt
          Migro100 is 4000K, ~ 142 Lumens/Watt

          The most efficient T5 bulbs are only 90 Lumens/Watt.
          The T5 bulbs (360 degree light) are at most 1.0 PPF/Watt.
          The most efficient T5 fixtures are at most 0.9 PPF/Watt.


          Also note the correlation between Lumens per Watt, PAR Light Output and Efficiency (PPFD and PPF)

          A Comparison of Fluorescent and LED T5 Tubes...



          Click image for larger version  Name:	photobiology.png Views:	0 Size:	1.36 MB ID:	681964
          Continuing Academic Horticultural Research has shown that White LEDs (Here; Warm=3500K, Neutral=4100K, Cool=5700K) have equivalent or Better spectrum for plant growth than Fluorescent...
          Pete R - Hudson Valley, NY - zone 5b

          Comment


          • #12
            This is what I bought and have been using, is this ideal for getting cuttings through winter? I’m not trying to fruit anything mind you, just want my cuttings to get some good light for leaf growth until March
            CA Zone 9B WL: Thermalito

            Comment


            • AscPete
              AscPete commented
              Editing a comment
              The 5000K CCT LED Light is more than adequate for plant growth, 4,500 Lumens (LM) equates to ~ 67.5 PPF output which can provide a calculated 168 PPFD coverage for an approximate 1' x 4' (30 cm x 120 cm) area. Good luck.

            • mwhight34
              mwhight34 commented
              Editing a comment
              Good to know Pete thanks for the response. I’ve really liked this light so far, i can even plug a heat mat into it and save space on the outlet. Doesn’t get hot so I can leave it on while I’m at work, I’ve got a Mylar safety blanket wrapped around the shelf to reflect all the light inward

          • #13
            I might add another Mars Hydro LED. I don’t want to drop the cash for pro lights, but these amateur dope grower lights grow figs from bud to ripe... I like my seedling wire shelving system with a 4’ 4-bulb LED per shelf. 2 bulbs at 2700K and 2 at 6500K. I can grow plants into the bulbs without burning.
            N. GA 7B
            UPDATED! Wish list: CDD Mutante, BFF, SE tolerant stone fruit, blackberries...

            Comment


            • AscPete
              AscPete commented
              Editing a comment
              Thanks for commenting. 4600K LED (2700K + 6500K average) is a good "Full Cycle" spectrum for Vegetative growth..

              I have a 4 bulb T8 fixture with 4000K LED Philips Instafit Tubes (2100 Lumens @ 17 watts, ~ 1.85 PPF/W each). They work quite well as "Seed Starting / Seedling" lights on a 16" x 48" wire shelf (~236 PPFD).

          • #14
            Recently Harbor Freight Tools started selling a LED 4ft single tube shop light that rates at 5000 lumins for 20 bucks. (70 watts consumption) And Home Depo has a 3ft LED single tube rated at 3000 lumins for only 12 bucks. Would these good to use as grow lights and good value? Sure seems good.
            Northern CA 9b W L- Ponte Tresa, White Madeira#1, Lampiera Prusch, Thermolito, Calabacita, Prat st. U. Rigato del Salento Pb

            Comment


            • AscPete
              AscPete commented
              Editing a comment
              Foodtreefield ,
              The problem of Lights without the Listings on their Labels is that they usually fall short of the claimed outputs, but the 3' Home depot light may be good buys (a couple) for a small seedling grow area;
              https://www.homedepot.com/p/Commerci...0-HD/305059320

              The actual Lux would have to be measured before any conclusions are reached.

            • BrandonP
              BrandonP commented
              Editing a comment
              I am using the three foot Home Depot lights in some of my set ups. They are working well for me. May not be the full 3k lumens, but I tend to put up more than the minimum required anyway. Working for figs, peach seedling and a lemon seedling so far.
              I'll probably buy a few more soon (need just one more grow area).

            • AscPete
              AscPete commented
              Editing a comment
              BrandonP ,
              Thanks for sharing that info.
              A digital Lux meter ($10.00 - $20.00) could be used to easily measure and or adjust the available lights;
              https://images-na.ssl-images-amazon....1wNA-1la8L.jpg

          • #15
            Lots of great information.

            For what it's worth, I started all my veggies indoors last winter with a $20 workshop LED light from Costco. They grew beautifully.

            Ideally, you want lights with lots of blue and red. With LEDs, they inherently emit narrow bands of light. They bands are selected to mix together to look white. You can look up thre spectrum of each light and work on optimizing. You can also find lights where to can transition the output for growth vs fruiting. I stick with the Costco workshop lights. They're inexpensive and good enough.
            Zone 6a/b - west of Boston
            Wish List: A fig-maple hybrid

            Comment


            • AscPete
              AscPete commented
              Editing a comment
              Thanks for commenting.
              The majority of White LED Bulbs and Fixtures available are Phosphor-Converted LEDs (~ 97% - 98%), they have Pale Yellow (Higher CCT) to Orange (which are Lower CCT) and Silicon Coatings over (discrete) Blue LEDs and create "White" Light; https://www.ourfigs.com/filedata/fetch?photoid=137191

              All the Costco LED Shoplights I've seen advertised have been standard 4000K White LEDs (Phosphor-Converted) viewed with a spectrometer the Percentage of Blue - Green - Red - FarRed is usually approximately 18% - 45% - 34% - 3% which provide a good broad spectrum for Full Cycle Vegetative Growth. https://hubbellcdn.com/brochure/hil_0401_cgs_ref_16.pdf

          • #16
            Pete, we just picked up a bunch of T8 - 4 foot long 2 bulb fixtures (model 1233) for our 18 inch x 48 inch shelves, 2 fixtures/shelf. We picked up 2 kinds of GE T8 LED bulbs that work with electronic ballasts, 4000k (1800 Lumens), and 6500k (1800 Lumens), 32 watt replacement, 1 bulb each type in each fixture. This is for fig cuttings as well as starting vegetable seeds. Will this setup work?
            WV Harpers Ferry Zone 6b

            Comment


            • AscPete
              AscPete commented
              Editing a comment
              Typically 3500K - 4000K White LED bulbs provide a better "Full Cycle" spectrum for healthiest plant growth, "Seed thru Flower".

              Your mix is ~ 5250 K (6500 +4000 / 2)...
              6500K Bulbs provide more Blue wavelengths which actually slow, reduce or retard vegetative growth of most plant species. When "Mixing" bulbs (Fluorescents or White LEDs) its been the industry and hobby practice to attain 3000K to 4000K for best overall growth. Good luck.

              BTW, The T8 Fixtures can use Fluorescent Bulbs (typically 2300 Lumens or ~ 25 PPF each and 32 watts) or LED Bulbs (typically 1800 Lumens or ~ 27 PPF each and 18 watts)...

            • WVMJack
              WVMJack commented
              Editing a comment
              It sounds like we would be a lot better off taking the 6500k out and just putting in some more 4000k bulbs, thanks Pete

          • #17
            IMO, some videos with interesting info and measurements of a couple commercially available Phosphor-Converted White LED Grow Lights, the White LEDs are the same type as that supplied in Household LED Bulbs and Tubes.








            And as mentioned a simple way to measure and adjust any "White Light" source is with an accurate and inexpensive (under $20.00) Digital Lux Meter...


            BTW, Although Grow Light Manufacturers are producing Whte LED Grow Lights with added "Red" Diodes for boost / increased efficacy (over 2.0 PPF/W) Academic Research has not concluded that there are any added benefits over Grow Lights with only White LEDs when supplying the same light intensity (umol/m2/s or PPFD). Academic Research has concluded that Red-Blue LED Grow Lights are not as productive as White LED grow Lights at the same / equivalent light intensity.

            Click image for larger version  Name:	rb to w led.jpg Views:	7 Size:	163.3 KB ID:	688796

            And a comparison of Commercial Grow Light and White LED Spectrums, note that the various White LEDs Temperatures have spectrum that are close / equivalent to the Commercial Grow Lights (Both HID and LED).
            Last edited by AscPete; 01-07-2020, 07:25 PM. Reason: added BTW...
            Pete R - Hudson Valley, NY - zone 5b

            Comment


            • #18
              Photobiology Simplified with Dr Bruce Bugbee


              Click image for larger version  Name:	content_street_24w_dual_led_spectral_distribution_with_mccree_curve.jpg Views:	0 Size:	232.6 KB ID:	707092
              4000K White LED "Grow Light"


              Lux Meter vs PAR Meter



              33,200 Lux x 0.015* = 498 PPFD (~ 1.8% @ 507 PPFD)
              Note; Lux Meters can be used with any light source when the Conversion Factor (offset) is known.
              * = Conversion Factor for 3000K - 5000K LEDs (Phosphor-Converted White LEDs)


              MH HID vs Highbay LED


              Click image for larger version  Name:	hid Led Comp-600.jpg Views:	0 Size:	40.0 KB ID:	707090
              425 Watt 4500K MH HID vs 225 Watt 3500K LED
              Pete R - Hudson Valley, NY - zone 5b

              Comment


              • #19
                To AscPete,

                I commented awhile back on my led HLG 100 watt lights. They are 4000k spectrum. I leave the lights on 24/7. I have noticed that my trees develop figlets very early, maybe too early? Example: I have an LSU Purple started in Nov from cutting that now is about a foot tall with figs growing size of a quarters. Im guessing that leaving the lights on 24/7 makes them fruit more instead of vegetative growth? What are your thoughts?
                RobertC-NEOhio Zone 6a.

                Comment


                • AscPete
                  AscPete commented
                  Editing a comment
                  ammo1a1970 ,

                  Some fig cultivars simply produce figs (Figlets) as soon as they start growing leaves, other produce figs after several nodes or after some time imcrement, not really dependent on Light.

                  Also LSU Purple has a reputation as a “3 Crop Fig” in warmer zones which may account for its prolific growth, it will continue to grow and produce figs late into the growing season. In my short season it’s late ripening but productive.

                • ammo1a1970
                  ammo1a1970 commented
                  Editing a comment
                  Do you think the lights being on all the time effect growth habits? If so, what is your preferred on off times?

                • AscPete
                  AscPete commented
                  Editing a comment
                  Robert C,
                  Yes.
                  The recommended maximum is 20 hrs on, but 16 hrs is more than adequate for cuttings and young plants.

              • #20
                - 2004 -
                Click image for larger version  Name:	NASA BGR LED trials-800px r1.jpg Views:	0 Size:	122.6 KB ID:	723350

                https://www.researchgate.net/publica...ettuce_Growth_ under_Red-_and_Blue-light-emitting_Diodes
                The addition of 24% green light (500 to 600 nm) to red and blue LEDs (RGB treatment) enhanced plant growth. The RGB treatment plants produced more biomass than the plants grown under the cool-white fluorescent lamps (CWF treatment), a commonly tested light source used as a broad-spectrum control.

                https://www.researchgate.net/publica...ource_for_plan ts_A_review_of_research_at_Kennedy_Space_Center
                Research has shown that the combination of red and blue LEDs is an effective lighting source for several crops, yet the plants under red and blue lighting appeared purplish gray. However, when 24% (36 µmol m–2 s–1) green light was added to red and blue LEDs, lettuce plants showed enhanced growth and had the green appearance, making visual assessment of plant health possible.

                - 2014 -
                https://ntrs.nasa.gov/archive/nasa/c...0150009399.pdf
                History of LEDs and plant growth. Initial testing of LEDs for plant growth was conducted at the University of Wisconsin and the Wisconsin Center for Space Automation and Robotics with funding from NASA in the late 1980s, and patents were awarded for this application in 1991 (7) and 1996 (8). The narrow-waveband nature of LEDs prompted researchers to use them as sources of single-color light to improve study of photobiology, photosynthesis, and plant physiology

                - 2016 -
                https://journals.plos.org/plosone/ar...l.pone.0163121
                Despite decades of research, the effects of spectral quality on plant growth, and development are not well understood. Much of our current understanding comes from studies with daily light interval (DLI) levels that are less than 10% of summer sunlight thus making it difficult to characterize interactions between light quality and quantity...
                ... Here we report the effects of eight blue and green light fractions at two photosynthetic photon fluxes (PPF; 200 and 500 µmol m-2 s-1; with a daily light integral of 11.5 and 29 µmol m-2 d-1) on growth (dry mass), leaf expansion, stem and petiole elongation, and whole-plant net assimilation of seven diverse plant species. The treatments included cool, neutral, and warm white LEDs, and combinations of blue, green and/or red LEDs.

                ... Collectively, these results indicate that:
                1. the effect of blue light on dry mass is primarily determined by changes in radiation capture and not by a direct effect on photosynthesis,
                2. the effects of blue light fraction are greater at higher PPF,
                3. there is a wide range in species sensitivity to blue light,
                4. green light fraction has a minimal effect on dry mass gain during early growth,
                5. the effects on leaf thickness and chlorophyll concentration in response to blue and green light fractions can be interpreted as a shade avoidance response,
                6. light quantity can have a bigger effect on plant shape than light quality.

                - 2017 -
                https://www.researchgate.net/publica...opment_and_Pho tosynthesis_of_Petunia_Grown_Under_White_or_Red-blue_LED_lights
                The results of this study demonstrated that white LED light may be more effective than RB LED light for cultivating petunia plants. However, this should not discourage the application of RB light or other narrowed-wavelength LED light systems for plant cultivation.
                (*Note; White LED ~ 4850K)

                - 2020 -
                https://www.canr.msu.edu/floricultur...20efficacy.pdf
                In 2014, we communicated the efficacy of LED fixtures that were then on the market. This marked the beginning of our use of the term fixture efficacy, which is the amount of photosynthetic light emitted (micromoles of photons per second, or µmol·s–1) divided by the amount of energy consumed (watts, which equals joules per second, or J·s–1) [PPF/W]. The resulting unit is micromoles per joule, or µmol·J–1. The most efficient LEDs in 2014 were as efficient as the most efficient conventional lamp, the double-ended 1,000-watt high-pressure sodium (HPS). In October 2018, the Design Lights Consortium (DLC) published technical requirements for a horticultural lighting fixture to become qualified and included in their Horticultural Lighting Qualified Products List (QPL). Qualified products are usually eligible for energy efficiency incentives and rebates from utility companies throughout the U.S. and Canada. Among the minimum qualifications are a 5-year warranty, photosynthetic light maintenance of at least 36,000 hours, and a minimum efficacy of 1.9 µmol·J–1.

                As we enter 2020, there are already more than 50 LED products on the DLC Horticultural Lighting QPL. The spectrum, amount of emitted light, and efficacy vary widely among fixtures. Some of the products primarily intended for high-intensity greenhouse lighting applications are listed in Table 1. A full list of products, including ones primarily for indoor lighting, as well as additional details, are available on the DLC website at www.designlights.org/horticultural-lighting. Information about each fixture was generated by accredited laboratories and thus is unbiased.The photosynthetic photon flux [PPF] refers to the amount of light emitted per fixture, and for those in Table 1, varies from 766 to 1,636 µmol·s–1. All of these fixtures include white LEDs. Ones that emit a low percentage of green light (less than 10%) indicate that there are relatively few white LEDs per fixture, and the light emitted will appear pink to us. Those with a higher green light percentage indicate a higher percentage of white LEDs per fixture and thus, the light will appear whiter.

                As of 2/27/2020 The DLC Horticultural Lighting QPL had 69 different Horticultural fixtures;
                https://www.designlights.org/horticu...ghting/search/
                ~ 88% (61) are LED Horticultural Lights are White LEDs or White LEDs with supplemental 660nm Red LEDs and infrequently 730nm supplemental Far-red LEDs.
                ~ 12% (8) are Red / Blue LEDs for supplemental Greenhouse Lighting.


                ~4000K LED plus 660nm Red Fluence "Greenhouse Spectrum" and 4000K LED Next Light...
                Pete R - Hudson Valley, NY - zone 5b

                Comment


                • #21
                  All this data from the industry but no measurements of your own.
                  What LED systems are you currently using?
                  ​​​​​
                  Fruit crazed in Vista CA. http://tangentvectors.org

                  Comment


                  • #22
                    Richard ,

                    Originally posted by AscPete View Post
                    LED Grow Lights 2020 - White LEDs; Household LED Bulbs and LED Tubes?
                    - 2016 -
                    https://www.ourfigs.com/forum/figs-h...909#post119909
                    https://www.ourfigs.com/forum/figs-h...747#post196747
                    https://www.ourfigs.com/forum/figs-h...172#post120172

                    - 2017 -
                    https://www.ourfigs.com/forum/figs-h...iy-grow-lights

                    - 2020 -
                    https://www.ourfigs.com/forum/figs-h...nd-high-output

                    Originally posted by Richard View Post
                    Let's face it. You are copying and pasting large quantities of advertising that you don't understand. How about you go measure some of these systems you're promoting. It'll do you good to get out of the house anyway.
                    We have nothing to Discuss.
                    I don't tolerate rude or condescending comments and remarks in real life and refuse to do so in virtual reality, IMO there is no excuse for rudeness.
                    Pete R - Hudson Valley, NY - zone 5b

                    Comment


                    • Richard
                      Richard commented
                      Editing a comment
                      Your measurements do not permit comparisons between systems. They only echo the misleading advertisements of the manufacturers.
                      Last edited by Richard; 03-02-2020, 06:28 PM.

                  • #23
                    A Good Video..., but
                    Note: The 0.015 Conversion Factor is only for 3000K - 5000K White LEDs (Phosphor-Converted) with 80+ - 90+ CRI

                    https://www.apogeeinstruments.com/co...n-ppfd-to-lux/

                    White Light Lux Conversion Factors LUX to PPFD (umol/m2/s):

                    0.0185 = Sunlight
                    0.0135 = Cool White Fluorescent (& CFL)
                    0.0122 = Mogul Base HPS Lamps
                    0.0130 = Dual-Ended DEHPS: ePapillion 1000 W
                    0.0141 = Metal Halide
                    0.0154 = CMH / LEC (CMH942): 4200 K CCT
                    0.0170 = CMH / LEC (CMH930-Agro): 3100 K CCT

                    Multiply the Lux by the conversion factor to get PPFD or Lumens by conversion factor to get PPF.
                    For example, full sunlight is 108,000 Lux or 2000 µmol m-2 s-1 (108,000 ∗ 0.0185).


                    This season I will be attempting to grow and fruit a few fig trees indoor under Household LED Grow lights, the grow area will be approximately 2' x 8' or 16 sq ft. Half of this area (8 sq ft) will be covered by a 24 bulb LED string Light Fixture, the other half will be covered by a High Bay LED Fixture. The "PAR" measurements will be made with the Benetech GM1010, but I also have a Dr. Meter LX1330B similar to the one in the linked Video, the measurements on both always within 1%, usually less. https://www.ourfigs.com/forum/figs-h...riptive-method

                    This 12 Bulb String Light can easily cover 2' x 2' or 4 sq ft and can also be used with PAR38 Bulbs for increased intensity; https://www.ourfigs.com/forum/figs-h...nd-high-output
                    Actual Measured Output 24 in x 30 in Area (5 sq ft) with Reflective Mylar Blanket Surround / "Tent":

                    @ 12 inches = 44,000 Lux / PPFD 660 umol/m2/s (avg)
                    @ 24 inches = 24,000 Lux / PPFD 360 umol/m2/s (avg)
                    @ 36 inches = 14,000 Lux / PPFD 210 umol/m2/s (avg)

                    Note: "Measured" = ~ 3600K (~ 14% Blue); 4 bulbs @ 5000K & 8 bulbs @ 3000K


                    Another example of a simple and inexpensive "higher output" fixture is the following which can cover approximately 1-1/2' x 1-1/2' or 2.25 sq ft.
                    Click image for larger version  Name:	7-Bulb LED Light.jpg Views:	0 Size:	187.8 KB ID:	723916

                    Fixture - $8.00, Socket-$1.50 and Bulbs-$1.00 ea. ($20.00)
                    7 bulb splitter with Sunbeam12 watt LED PAR30, 3000K, 840 Lm / 5880 Lm total.
                    Calculated;PPF 88.2 umol/s, 392 PPFD umol/m2/s @ 2.25 sq Ft (18" x 18", ~ 0.225 sq m)

                    Measured; Benetech GM1010 Digital Lux Meter ($15.00)
                    @ 6.0" = 62,000 Lux (PPFD 930 umol/m2/s) (center point)
                    @ 12" = 40,000 Lux (PPFD 600 umol/m2/s) (center point)
                    @ 24" = 16,500 Lux (PPFD 247 umol/m2/s) (center point)
                    @ 36" = 9,000 Lux (PPFD 135 umol/m2/s) (center point)

                    Kill A Watt P3 Meter ($25.00)
                    86.2 Watts 119.8 VAC, 60.7 Hz, 0.92 PF, 0.77 Amps.
                    Pete R - Hudson Valley, NY - zone 5b

                    Comment


                    • Noah Mercy
                      Noah Mercy commented
                      Editing a comment
                      Clearly a man after my own heart, lol...

                  • #24
                    Here not being a physicist I simply got a couple of "80 watt 8000 lumen 3000K fan shaped LED lamps on Amazon. They fit a standard light socket and hung them over my "grow spa"bench that also served as an engineering work bench when plants are removed. With this light my fig cuttings are thriving and tomato seedlings are making record healthy growth. These cost 11 bucks each and replaced a clunky 2 bulb T12 shoplight that also produced inadequate light for me to work with small parts as well.Now I see eveything I do wrong before it's too late! And the plants do everything right.
                    Z8A NC SANDHILLS

                    WISH LIST BURGAN UNK, ZAFFIRO,

                    Comment


                    • AscPete
                      AscPete commented
                      Editing a comment
                      Thank for commenting.
                      Agreed, you do not need academic degrees to be a gardener...

                      I’ve always advocated using basic tools e.g. an 8 piece measuring cup set ($1,00) for fertilizers, amendments and cuttings’ irrigation, having measured amounts allow easily repeating successes, just like in baking and using any recipe. IMO a simple Digital Lux Meter ($15.00) for use with Any dedicated White Light source Grow Lights is just another tool to use for repeatable success, it will allow you to position the fixture to get the “best MPG” (miles/gal)...

                    • YATAMA
                      YATAMA commented
                      Editing a comment
                      Pete, I used a light meter back in the day when was doing film photography and that meter really helped. I do not have any academic degrees in physics for sure,only chemistry which sure doesn't overlap much! But here after seeing how my plants are doing under those lights I got I now regard THE PLANT as the absolute best light meter anyone could dream of!Indicates finally got the CORRECT level of light my former clunky shop light did not provide.
                      I really appreciate the detailed physics you and some others provide here for people capable of understanding light science.For me though your comments on plant chemistry and water do make me smile,though; we're on board with all that!

                    • AscPete
                      AscPete commented
                      Editing a comment
                      Agreed, you down need higher education or degrees to successfully grow plants, I know someone that only completed 3rd grade, had a green thumb and worked as a respected groundskeeper at the Botanical Gardens...
                      You can always get lucky with the placement of your lights, but proper placement increases success.

                      You don't need advanced math nor a Digital Lux Meter to do the basic calculations, for example;

                      8000 Lumens = PPF of 120 umol/s (Total Output) [8000 x 0.015]

                      PPF 120 umol/s = PPFD 150 umol/m2/s (Average over 2' x 4' area, 8 sq ft or ~ 0.8 sq m) [120 / 0.8]

                      PPFD 150 umol/m2/s = 10,000 LUX [150 / 0.015]

                      There are other factors like the height of the fixture above the plant canopy and coverage footprint but the PPFD of 150 umol/m2/s is more than adequate for healthy propagation and early growth of fig cuttings;
                      https://www.ourfigs.com/forum/figs-h...r-fig-cuttings

                      150 PPFD @ 12 hours "ON" is a DLI of 6.5 Mol/m2/day
                      https://www.ledtonic.com/blogs/guide...d-requirements

                      All done without a Lux Meter ... And can be done with almost any light source if the Light Fixture's PPF are known or can be calculated as above.

                  • #25
                    well I take your word and my plant's as well for that.What am really waiting for to do rest of my propagation is the SUN and warmer ambient temps.Especially to get my sweet potatoes going.next to figs easiest crop to grow here.
                    Z8A NC SANDHILLS

                    WISH LIST BURGAN UNK, ZAFFIRO,

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