Grow lights in greenhouse

Discussion in 'Greenhouse Growing' started by Snorky85, Jan 19, 2019.

  1. Snorky85

    Snorky85 Total Gardener

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    I'm actually considering getting some grow lights for my new greenhouse set up. I thought maybe sowing some seeds now and having the grow lights on for a couple of hours each day may work and stop seedlings going leggy.

    Has any body got grow lights and use them in this way?
     
  2. sandymac

    sandymac Gardener

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    Much the same I use LED grow lights in the conservatory (fancy greenhouse) for my tomato seedlings.
    Vipar Spectra Model V450 dual functions grow and bloom.
    So bright you can not look directly at the lights even from several metres away.
    Gone are the days of spindly windowsill seedlings.
    I can start my first sowings in January continuing February then march, rather than having to wait until March for the first sowing.
    This gives me ripe fruit from May until the frost gets them Oct/Nov
    Regards Sandy
     
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    • Snorky85

      Snorky85 Total Gardener

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      Ooh thanks @sandymac

      What kind of distance do you have the lights from the seed trays? and how many hours a day do you leave it on?
       
    • Scrungee

      Scrungee Well known for it

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      I have a grow light box at the far end of my greenhouse, the base is at staging level, and over the top is heavy gauge polythene dpm to protect electrics under, with a propagation heat mat over the top to make the most of the space, only starting to use when the g/h heating went on.

      It didn't get put on until just before uni Easter hols for the last few years, as I used our daughter's bedroom as a 'pop up' propagation, growlight tent, potato chitting area, etc., etc., but now she's back for a year before returning for her Masters, I need alternative arrangements.

      So this year I need to think about putting my greenhouse heating on earlier, or maybe a combination of that together with more intensive use of my study, possibly with 2 tier LED growlights by the window, and maybe another colder LED growlight area in my shed.

      They'll need a proper day's light as soon as they emerge. Until the area(s) under lights becomes full mine get turned off for a period each day, then they get rotated under them in either 8 or 12 hour shifts. N.B. Leaving under lights 24/7 can adversely affect leaves.
       
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      • Snorky85

        Snorky85 Total Gardener

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        So @Scrungee ....you are the perfect person to ask....how much does running the grow lamps cost you?
         
      • JWK

        JWK Gardener

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        I use growlamps both in a spare room and in the greenhouse. I use a power monitor to check the electric consumption in the greenhouse, something like this:
        Energenie Energy Saving Power Meter Plug | Wickes.co.uk

        I also have a fan heater to keep the greenhouse at 6C and that is the most expensive thing to run, obviously depending on the weather conditions. It costs me £40 to £50 over the winter months for both lights and heater. This is in a small 8X8 greenhouse with bubble wrap insulation. Without insulation the cost would probably double or triple.

        The lights themselves are fairly cheap to run, my system is old using fluorescent tubes rated at 80W - if they are on 10 hours a day it will cost about £3/month (assuming electric cost at 12p/kWh).

        With a modern efficient LED growlamp I guess it would consume 80% less power - so maybe 60p per month.

        It will be interesting to know if my figures tally with anyone else.


        The only reservation I have with lights in my greenhouse is being a suburban garden it makes the greenhouse very conspicuous and neighbours may well think I am growing something very dodgy in there. So I use a lightbox to make it less obvious.
         
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        • WeeTam

          WeeTam Total Gardener

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          I did mine this way 36w ÷ 1000 x 18 hours x 30 days x 15p = not much per month. Think it was about £3.50 pm ish :scratch:

          Edit £2.92 per month.
           
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          • Snorky85

            Snorky85 Total Gardener

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            OOh thank you all for your info. I will weigh up whether it is worth it or not....initial outlay and monthly running costs taken into consideration :)
             
          • CanadianLori

            CanadianLori Total Gardener

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            My cost here is 65p per kwh so I switched to LEDs as I could afford to switch over from tubes.

            I wish we had milder winters because if we did, I'd use a little heating in the greenhouses and LEDs out there to extend the day.

            So @Snorky85 if you are in a position to put the lights out there, you've got a great place for seedlings. :)
             
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            • WeeTam

              WeeTam Total Gardener

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              I found the heat from my led heated the area where the seeds were. 31'c :phew: Rocket seed germinated in 48 hours.
              The 36w cool white 6000k circular led is using 50w in reality, getting warm on the back. Light is inside a polystyrene fish box covered with polystyrene lid.

              Switched it all off, abandoned the seeds just in case it over heated and burnt the house down when im away for a few days.

              Would have worked a treat in a greenhouse.
               
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              • Scrungee

                Scrungee Well known for it

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                (I fell asleep drafting this and have just woken up!)

                If small, cheapo LED tubes are used they are rated at 9w, so (just as an example) five over an area of 600 x 450mm )and maybe a little bit more around the perimeter), 5 x 9w = 45w, 1 unit = 1kw(1,000w)/hour, so 1 hour @ 45w = 1/22 (45/1,1000) of a unit.

                If you pay, say 15p/unit, then one hour would cost 1/22 x 0.15 = 0.6p/hr.

                We're on Economy7, so try to restrict initial use to around 7 hours/day, which pro-rata would be 0.3p/hr.

                But when things get really busy I swop stuff 3x a day, and as that coincides with additional daylight


                But as the seedlings grow, you're going to need an ever increasing area under lights to prevent the plants from going leggy.

                Early sowings soon fill my 1.2 x 0.75m indoor growbox, then they take turns for 12 shifts under the lights, then I rig some more lights up on my desk next to a window whilst continuing to swop stuff around until it gets so crammy I'm forced to put the g/h heating on and start using the lights in there, which also start taking turns under those lights.

                It's got to the point where I need either a further setup in my shed, or I grow less stuff.
                 
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                  Last edited: Jan 20, 2019
                • Snorky85

                  Snorky85 Total Gardener

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                  Thanks @Scrungee I knew you would have an economical system set up. :)
                   
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                  • sandymac

                    sandymac Gardener

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                    Hi Snorky
                    My lights are 24" above the trays on a plywood board (2ftx 4ft)with a cut out for the light and I have rigged up a silver curtain that goes around the trays when the lights are on to reflect the light. This allows me to get six seed trays in the area with plenty of space between trays.
                    I presently use the lights 3 hours per day , this will drop to two hours at the end of Febuary.
                    I sometimes give them an extra hour if it has been a particularly dull day.
                    I have a power meter and have just done a test which tells me the lights use 2 pence per hour so 6 pence a day in second half Jan / first half Feb. Monthly total £1:80
                    2 hours per day second half Feb first half March. so 4 pence per day Monthly total £1:20
                    However if you are looking at cost the lights are expensive over £100. it is my only hobby so I tend not to look at cost just best tool for the job.
                    The lights have made my season much longer and I am not now straining at the bit to get things started. I used to use an old aquarium light set up with 3 foot full spectrum fluro tubes
                    but they were not as good as the LED as I had them just above the plants for 6 hours a day and my plants were still a little leggy.
                    Hope this helps regards Sandy should have said my lights are 450w
                     
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                      Last edited: Jan 20, 2019
                    • Snorky85

                      Snorky85 Total Gardener

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                      Thanks @sandymac great to know the info from your power meter.

                      I looked at the type of lamp you have put in your link and it looks decent. I dont mind spending around that for the initial outlay and good to know it does actually make a difference. Also £2 a month aint bad!
                       
                    • Snorky85

                      Snorky85 Total Gardener

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                      :snorky: What grow lights do you have? I'm thinking of getting
                      the Vipar Spectra Model V450 dual functions grow and bloom from Amazon that @sandymac uses.

                      I had sown some tagetes 2 days ago and they've already sprouted with the heat mat I'm using! Need to buy a lamp asap I think!
                       
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