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Tomatoes under lights

AdRockAdRock Posts: 241
in Problem solving
Hi, has anyone had any experience growing tomatoes under hydro lights? I’ve got some seedlings which have been doing ok in the greenhouse, but I’ve added some hydro lights for the evenings and the tomato leaves seem to curl up and maybe even turn a bit purple underneath when the lights are on. Am I causing damage by exposing to too much light? The lights are a good 2ft away from the seedlings 


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  • SkandiSkandi Posts: 1,717
    Put a min max thermometer out there, purple colouring is often an indicator that they are getting to cold.
    The plants don't look that happy to be honest, what did the instructions that came with the lights say about distance? 2ft is a long way away and I wonder if they are not stretching for the light, especially with that cucumber? seedling in the background getting so tall.
    I grow my tomato starts inside under lights but I don't have any experience with plant lights as I use florescent tubes, and they need to be very close to the plants. 1-2 inches from the leaves. Your light may well fry the plants if you put it that close.
  • AdRockAdRock Posts: 241
    Thank you. I’ve already got a min max thermometer and gets down to about 8 at the moment on cold nights... not sure if that’s ok or if I need the heater on.

    The tall seedlings at the back are the kids sunflowers! 


  • AdRockAdRock Posts: 241
    This is how the seedlings look this morning... much better! I think I’ll bring the light closer to them tonight and see what happens


  • Pete.8Pete.8 Posts: 10,937
    Minimum temp for tomatoes is 13c
    To see how close the light should be, hold your hand under the light where the plant tops will be, if it's just warm that's good.

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • FairygirlFairygirl Posts: 53,966
    I'd agree with @Pete.8. It's the night time temp you need for them. It's also the fluctuating temp that can be a problem.
    At the moment, many parts of the country have had temps in the 20s during the day, but it's April, not June. That drop through the night is a big factor, so they need warmth.
    It's why we can't grow them outside here - the temps in summer aren't reliably in double figures or low teens.  :)

    PS - @markos - I'd get those sunflowers outside during the day and harden them off when they get a wee bit bigger. They don't need a greenhouse. It's better for them to  be grown a bit 'hard' anyway, as you'll get stronger plants  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • AdRockAdRock Posts: 241
    Pete.8 said:
    Minimum temp for tomatoes is 13c
    To see how close the light should be, hold your hand under the light where the plant tops will be, if it's just warm that's good.
    Great advice, thanks very much 
  • AdRockAdRock Posts: 241
    Fairygirl said:
    I'd agree with @Pete.8. It's the night time temp you need for them. It's also the fluctuating temp that can be a problem.
    At the moment, many parts of the country have had temps in the 20s during the day, but it's April, not June. That drop through the night is a big factor, so they need warmth.
    It's why we can't grow them outside here - the temps in summer aren't reliably in double figures or low teens.  :)

    PS - @markos - I'd get those sunflowers outside during the day and harden them off when they get a wee bit bigger. They don't need a greenhouse. It's better for them to  be grown a bit 'hard' anyway, as you'll get stronger plants  :)

    Thank you! I’ll get the sunflowers out soon... the kids are looking forward to watching them grow
  • FairygirlFairygirl Posts: 53,966
    edited April 2020
    Let them get a wee bit bigger - enough size to put in a slightly bigger pot. Those are just the seed leaves.
    When they're filling a three inch pot, outside for a little while each day, increasing it according to weather, until they're sturdy enough to leave out completely. Watch out for slugs with them too.
    Just keep them sheltered once they're out all day and night - in case you get some rough weather before they can go in the ground.  :)
    Good luck with them - it's always fun for kids to 'compete' with them - especially just now  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • KiliKili Posts: 1,091
    Markos, looking at your pots I would suggest you sieve the compost ( next time you sow) to get rid of all the larger bits in there. Young root growth will fare better if it doesn't have to negotiate all the lumps and bumps introduced by all that bulky stuff in the compost.

    kili

    'The power of accurate observation .... is commonly called cynicism by those that have not got it.

    George Bernard Shaw'

  • AdRockAdRock Posts: 241
    Kili said:
    Markos, looking at your pots I would suggest you sieve the compost ( next time you sow) to get rid of all the larger bits in there. Young root growth will fare better if it doesn't have to negotiate all the lumps and bumps introduced by all that bulky stuff in the compost.

    kili

    Thanks! Great tip, I did add some vermiculite so that might be too big as well? 
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