mwaller
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When is the he appropriate time to remove the humidity hood?
Do I need a heat mat to start seeds?
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You can remove the hood once most of the seed has germinated.
About the light period timing, some home-growers experience very early, sometimes bizarre timing of plants going to bud, resulting in stunted plants. There is some debate about the possible causes of this. One possibility is that going from 24 hour light to outdoor light signals the plant that the growing season is coming to an end.
I don't know if this is the case. Unfortunately, a brief exposure to light (say, you click on the ceiling light to have a look before bedtime) has a physiologic effect similar to keeping the lights on until that nighttime peek. So plants that are grown indoors are exposed to unpredictable and often unaccounted for lighting periods. Passing headlights at night can also do the same thing.
Bob
About the light period timing, some home-growers experience very early, sometimes bizarre timing of plants going to bud, resulting in stunted plants. There is some debate about the possible causes of this. One possibility is that going from 24 hour light to outdoor light signals the plant that the growing season is coming to an end.
I don't know if this is the case. Unfortunately, a brief exposure to light (say, you click on the ceiling light to have a look before bedtime) has a physiologic effect similar to keeping the lights on until that nighttime peek. So plants that are grown indoors are exposed to unpredictable and often unaccounted for lighting periods. Passing headlights at night can also do the same thing.
Bob
greenmonster714
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Its good to read others input on light cycles. About the tobacco plant. How does it trigger itself into flowering? Is it a light cycle thing or is it a certain amount of time when the plant triggers? I know many plants will flower once the days get short light periods. Usually around 12hrs or less. I guess it's their way of realizing the end of summer is near so they flower to make seed. It's been my experience with 12hr plants that if one maintains a cycle of light for at least 12hrs or more a day. The plant will stay in a vegetative stage and not trigger flowering. A example is I often took clones off of flowering plants and set them on a 24hr cycle. They would reverse and return into a veg state until once ahain turned back into the 12hr cycle. The flowering clone would branch out like mad. Both raising the size and yield of the plant. At the moment i have my tobacco under 24hr light. Not knowing the plant very well makes me wonder. I may have to throw a timer on them. I dunno. Your right Bob. This subject has been debated to death many times.
mwaller
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mwaller
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So, my seedlings are still very small, but a few are starting to get their second set of leaves. At what point should I consider adding a bit of fertilizer to their water? Is it too soon?
ChinaVoodoo
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Plant growth doesn't halt when the lights are turned off, so I don't think there's much of a call for 24hr light. In photosynthesis, the plant combines water and carbon dioxide with the energy of light, forming glucose. Meanwhile, the plant performs cellular respiration within their mitochondria, just like animals, in which oxygen is combined with glucose to form adenosine triphosphate (ATP). The plant then uses this ATP for all sorts of metabolic functions. These are the anabolic functions which build and transport the structures, proteins, etc that grow the plant. Normal respiration takes place 24 hrs a day. There should be enough photosynthesis already occurring with your grow lights in 12 hrs for the plant to respire all day. If the lightwasnt intense enough, longer periods would help, I imagine. But the idea of indoor growing is that the lights are optimal brightness already.
ChinaVoodoo
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I plan my light schedule so that I gradually increase my light hours to be slightly behind what's happening outside. The day I plant in the third week of May the sun will be out for 16hrs and 15 minutes, so I start at 12 hours and gradually work up my grow lights to 14 hrs and 15 minutes. In mid May. That way when I plant them outside, they perceive the same increasing day length that they were in the grow room, and know that there's still plenty of time to flower. From what I've been reading, this should prevent flowering. I'm sure I'm making a few assumptions here, but it can't be good to drop from a long day to a short one when you plant outside. Pot growers do that intentionally, going from 16-24 hrs a day, then dropping it to 12 to induce flowering.
To add to the day period issue, plants perceive the red tint of sunset as a signal distinct from simply a decrease in light.
Bob
Bob
ChinaVoodoo
Moderator
That must be why the guys at the indoor garden store recommend high kelvin lights for vegetative growth and low kelvin lights for flowering.
greenmonster714
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What causes the tobacco plant to flower? Is it a time issue or a light cycle? I know they self pollinate so I would assume it is a set time. Being different for each and every variety.
ChinaVoodoo
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The amount of day/night time causes plants to flower. Every species/variety of species has a different set point.
http://nzetc.victoria.ac.nz/tm/scholarly/tei-Bio06Tuat01-t1-body-d1.html
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