Lighting Quick seedling question
- Thread starter PoisonIvy
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Good morning Poison!
For seedlings; you want to keep the lights higher than you normally would once they are established plants. For a MH/HPS light; a good rule of thumb is around 24 to 36 inches for seedlings (and I would err on the side of caution and lean more towards that 36 inches.) Is your reflector open air? Vented hood? In my opinion; it's far easier to fix the results of a light that's a bit too far away than it is to fix the problems from a light too close.
Another good rule of thumb is to take the back of your hand and place it at the top level of your plants, so the back of your hand (not your palm) is facing up towards the light. Hold it there for about 10 seconds. If it's uncomfortably warm for you; it's uncomfortably warm for the plants. You can test this out yourself by putting your hand 12 inches from the light and testing. Them move your hand down (or the light up) in 6 inch increments. This is a good way to get a feel for just how much a few inches makes a difference.
Hope that helps bro!
For seedlings; you want to keep the lights higher than you normally would once they are established plants. For a MH/HPS light; a good rule of thumb is around 24 to 36 inches for seedlings (and I would err on the side of caution and lean more towards that 36 inches.) Is your reflector open air? Vented hood? In my opinion; it's far easier to fix the results of a light that's a bit too far away than it is to fix the problems from a light too close.
Another good rule of thumb is to take the back of your hand and place it at the top level of your plants, so the back of your hand (not your palm) is facing up towards the light. Hold it there for about 10 seconds. If it's uncomfortably warm for you; it's uncomfortably warm for the plants. You can test this out yourself by putting your hand 12 inches from the light and testing. Them move your hand down (or the light up) in 6 inch increments. This is a good way to get a feel for just how much a few inches makes a difference.
Hope that helps bro!
Here's a handy chart to give you an idea of where the light is used most efficiently.
Be aware that it doesn't take heat into account.
You could hang a thermometer at canopy level - if you're pushing 85f+ you might hit trouble, so back the light away - or take cooling measures like more air exchange or an air con if needed.
Dont worry too much if you can't get it bang on (and without an aircooled hood, chances are you won't)
For the little one - I'd say 36" is about right - if it starts to get lanky, lower it a bit if you can, and stake it to a pencil or whatever so it doesn't fall over and snap when the leaves get heavy (or when you spray them)
A little fan pushing your little girl around will help the stem get strong
Hope this helps.
all the best
Blue ^_^
Be aware that it doesn't take heat into account.
You could hang a thermometer at canopy level - if you're pushing 85f+ you might hit trouble, so back the light away - or take cooling measures like more air exchange or an air con if needed.
Dont worry too much if you can't get it bang on (and without an aircooled hood, chances are you won't)
For the little one - I'd say 36" is about right - if it starts to get lanky, lower it a bit if you can, and stake it to a pencil or whatever so it doesn't fall over and snap when the leaves get heavy (or when you spray them)
A little fan pushing your little girl around will help the stem get strong
Hope this helps.
all the best
Blue ^_^
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