Light heights, & intensity seedling to flower
- Invisible Sun
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Light heights, & intensity seedling to flower
We get asked a lot about what height & intensity of light for seedlings & veg cycles,l are best, so here are a few tips to help you get the best out of your LED and not suffer any slow growth from over lighting.
Tip 1 _ dimming is the same as moving your light further away. The reverse is also true, if you dim your light you can move it closer. A good way to Take advantage of lower running electricity costs.
Tip 2 _ Cuttings need hardly any light to root. Don't over do it. Literally just 5w of led light at 12 inches away is all you need. Leave it on constantly
Tip 3 _ Seedlings need very little light too when compared to flowering plants. For a reference In the pic attached you'll see a par rating of 250 ppfd , the fixture in use is the ISH150 BR @12 inches from the pot tops. This fixture is dimmed to 40w. Let the plants grow into the intensity they want, it's only a few inch don't worry about stretching. More light could be counter productive.
Tip 4 _ more light doesn't equal faster veg. In veg less is better when using LED 15w per square foot is ample. Too much light will have a negative impact.
Tip 5 _ purple leaf stems can be an early sign of too much light in veg. If you find purple leaf stems dim your light until new growth stays green , and use that power setting as your reference point.
Tip 6 _ when transitioning into flower, slowly increase your lights power over the first 2 weeks of the cycle.
Tip 7 _ if possible utilise Sunrise and Sunset timings for stress free night / day transitions.
Tip 1 _ dimming is the same as moving your light further away. The reverse is also true, if you dim your light you can move it closer. A good way to Take advantage of lower running electricity costs.
Tip 2 _ Cuttings need hardly any light to root. Don't over do it. Literally just 5w of led light at 12 inches away is all you need. Leave it on constantly
Tip 3 _ Seedlings need very little light too when compared to flowering plants. For a reference In the pic attached you'll see a par rating of 250 ppfd , the fixture in use is the ISH150 BR @12 inches from the pot tops. This fixture is dimmed to 40w. Let the plants grow into the intensity they want, it's only a few inch don't worry about stretching. More light could be counter productive.
Tip 4 _ more light doesn't equal faster veg. In veg less is better when using LED 15w per square foot is ample. Too much light will have a negative impact.
Tip 5 _ purple leaf stems can be an early sign of too much light in veg. If you find purple leaf stems dim your light until new growth stays green , and use that power setting as your reference point.
Tip 6 _ when transitioning into flower, slowly increase your lights power over the first 2 weeks of the cycle.
Tip 7 _ if possible utilise Sunrise and Sunset timings for stress free night / day transitions.
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- Finchmad_79
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Re: Light heights, & intensity seedling to flower
What height/ distance from canopy would you recommend for the likes of your Uv or far/deep red supplement lights?
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- wutang (Sat Jul 23, 2022 6:53 pm)
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Re: Light heights, & intensity seedling to flower
Hey @Invisible SunFinchmad_79 wrote: βThu Mar 17, 2022 6:27 pmWhat height/ distance from canopy would you recommend for the likes of your Uv or far/deep red supplement lights?
I'd like to know the same. Also for the 530 that I've got ready to go in my 1.2x.1.2m tent. I've got the far red too and not exactly sure on timings on when to turn on and off?
I correctly use a t5 twin set up for seedlings under a propagator. Would your ish150 be suitable to replace this for seedlings. Im coming from HPS so want to make sure I get it right.
Thank you
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- Invisible Sun (Sun Jul 24, 2022 10:46 am)
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Re: Light heights, & intensity seedling to flower
Haha, I'm switching from HPS to LED too. Good info here.
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Re: Light heights, & intensity seedling to flower
Hey wutangwutang wrote: βSat Jul 23, 2022 6:56 pmHey @Invisible SunFinchmad_79 wrote: βThu Mar 17, 2022 6:27 pmWhat height/ distance from canopy would you recommend for the likes of your Uv or far/deep red supplement lights?
I'd like to know the same. Also for the 530 that I've got ready to go in my 1.2x.1.2m tent. I've got the far red too and not exactly sure on timings on when to turn on and off?
I correctly use a t5 twin set up for seedlings under a propagator. Would your ish150 be suitable to replace this for seedlings. Im coming from HPS so want to make sure I get it right.
Thank you
The far red should only be used for 15 minutes at lights off.
The main light is probably a bit strong for seedlings so I'd dim it right down which will take you to about 60w then maybe position it about 22-30 inches away, start at 30 inches I'd say.
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Re: Light heights, & intensity seedling to flower
If your using your far red light to do the Emerson effect which Iβm led to believe causes the plant to wiggle aka if a plant "senses" a greater ratio of far-red to normal light then it "knows" that obstructions or other plants are close to it. This causes the plant to react. It knows that it is much less productive to grow laterally outwards where there are obstructions or another plant's leaves already there. The obstructions or other plant's leaves will will just end up shading its own leaves. Instead, it puts its energy into growing vertically to reach for where the light is. In other words, it stretches upwards, increasing internodal length. This is called the "shade avoidance" effect aka the Emerson effect.Invisible Sun wrote: βSun Jul 24, 2022 10:46 amHey wutangwutang wrote: βSat Jul 23, 2022 6:56 pmHey @Invisible SunFinchmad_79 wrote: βThu Mar 17, 2022 6:27 pmWhat height/ distance from canopy would you recommend for the likes of your Uv or far/deep red supplement lights?
I'd like to know the same. Also for the 530 that I've got ready to go in my 1.2x.1.2m tent. I've got the far red too and not exactly sure on timings on when to turn on and off?
I correctly use a t5 twin set up for seedlings under a propagator. Would your ish150 be suitable to replace this for seedlings. Im coming from HPS so want to make sure I get it right.
Thank you
The far red should only be used for 15 minutes at lights off.
[youtube] https://youtu.be/YmiGDdrt7gM[/youtube]
So your using the Emerson effect need it on longer than just 15mins right?
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- waxjess420
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Re: Light heights, & intensity seedling to flower
Some handy tips there, especially the one about the purple stems!!
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- JJ
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Re: Light heights, & intensity seedling to flower
What about the purple uva usages
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- wutang
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Re: Light heights, & intensity seedling to flower
Cheere @Invisible SunInvisible Sun wrote: βSun Jul 24, 2022 10:46 amHey wutangwutang wrote: βSat Jul 23, 2022 6:56 pmHey @Invisible SunFinchmad_79 wrote: βThu Mar 17, 2022 6:27 pmWhat height/ distance from canopy would you recommend for the likes of your Uv or far/deep red supplement lights?
I'd like to know the same. Also for the 530 that I've got ready to go in my 1.2x.1.2m tent. I've got the far red too and not exactly sure on timings on when to turn on and off?
I correctly use a t5 twin set up for seedlings under a propagator. Would your ish150 be suitable to replace this for seedlings. Im coming from HPS so want to make sure I get it right.
Thank you
The far red should only be used for 15 minutes at lights off.
The main light is probably a bit strong for seedlings so I'd dim it right down which will take you to about 60w then maybe position it about 22-30 inches away, start at 30 inches I'd say.
So is that 15mins after lights off...or the last 15mins before lights off?
Going to get everything set tonight so thats helped massively. Thank you
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Re: Light heights, & intensity seedling to flower
@Invisible Sun whilst we are on topic...is there any problem using your lights with tp link hs110 smart plugs with energy monitoring? When I previously said I used this with HPS someone mentioned that I shouldn't use them, but the reasons were beyond my electrical knowledge