starting your plants under '' lights'' > share your experience,

[NRustica]

I always start mine under 4' 32watt bulbs. They do great there. I keep them as close to the plants as possible.

 

[Jitterbugdude]

Are these "regular" shop light bulbs or spectrum specific bulbs?

 

[Fisherman]

Small update 6-11-13:
Started 2 flats of seedling a week or so apart under a floresent shop lite which had 1 grow lite and 1 regular brite light. At the end of the flat I had a 100 watt heat lamp and covered the flat with plastic dome.
Both flats were in same area and the ones closest to the heat lamp didn't germinate well and the next 4 6-packs sprouted like 200% better on the 6-packs under the grow lite. The remaining 6 6-packs germinated well and.

I can rule out one flat as poor seeds in the end by the heat lamp as all came from same seller.

pic explains theory better :



The regular bulb is the one over the back side of flat in both instances.

 

[Knucklehead]

Are these "regular" shop light bulbs or spectrum specific bulbs?

The one I used until I got some fluorescent tubes was a 500 watt halogen that threw off heat like an oven. I ditched it as soon as possible. Then I went with heat mats under the flats and fluorescent aquarium/plant bulbs.

 

[AmaxB]

The one I used until I got some fluorescent tubes was a 500 watt halogen that threw off heat like an oven. I ditched it as soon as possible. Then I went with heat mats under the flats and fluorescent aquarium/plant bulbs.

For light that is exactly what I used 4 footers and they worked well did not use heat mat but think it is a good Idea.

 

[deluxestogie]

Can you site some references for that statement? I'd love to read some real studies on the subject.

Sky,
That was a great question. It took me several hours to track down scattered sources that I've come across over the past few years. I should start by saying that I misspoke about my germination methods. These were not in total darkness, as I had implied. Rather, the translucent plastic cups that contained my germination mix, and onto which I lightly sprinkled tobacco seed, were held in the low 80s for temp, and exposed only to incidental, ambient room light--never to direct sunlight--until after germination. The only exceptions were with the FTT grow-outs, some attempts being exposed to several hours of direct sunlight each morning.

So...here are some references:

Havana 425...light is required to trigger germination of this variety....

http://www.seedbiology.de/pdf/planta96.pdf

[tobacco] Seed stored under proper conditions for several months, however, usually lose this dormancy.
...seed lots can vary greatly in their response to priming, even within a cultivar. Because of this variability, the optimum priming conditions must be determined for each seed lot in order to obtain the greatest seed-priming response. Preliminary research by Smith et al. demonstrated differences in cultivar response to priming. For example, priming increased the rate of emergence of NC 71, NC 72, and K 394, but decreased the emergence rate for K 326 and K 346.

http://www.tobaccoscienceonline.org/doi/pdf/10.3381/0082-4623-45.1.6

Nicotiana species differ in the degree of seed dormancy...: N. tabacum and N. sylvestris have a low level of dormancy (exception: photodormancy of N. tabacum cv. Havana 425...)
Brief treatment of imbibed photodormant seeds with red light activates the phytochrome signal transduction pathway resulting in the release of photodormancy and the promotion of germination.
This effect varies greatly for different seed batches as reported for several tobacco cultivars.

http://www.seedbiology.de/dormancy.asp#arabidopsis

Two recent publications provide evidence for gene expression in air-dry Nicotiana seeds during after-ripening. A rapid promotion of testa rupture of Nicotiana tabacum seeds occurs after ca. 60 days of dry storage...

http://www.seedbiology.de/afterripening.asp

http://www.jstor.org/discover/10.23...2&uid=70&uid=4&uid=3739256&sid=21102303412141

The above tables are partial results of some light priming experiments. What is of interest is the durations of light exposure (seconds to minutes, rather than hours or days).

My impressions from these and other similar sources are that:

• most tobacco seed that has been properly stored over the winter is not photodormant
• a small number of specific varieties are clearly photodormant (e.g. Havana 425)
• exposure to red light for some number of minutes, after the seed has imbibed water, will overcome any photodormancy
• optimal timing of light exposure is between 2 and 5 days after sowing
• the degree of photodormancy is dependent on germination temperature
• those who undertake these studies seldom know much about tobacco varieties other than the tiny number of varieties that they work with
• nearly all of the published studies on tobacco seed germination are under unnatural conditions--precisely filtered wavelengths of light; filter paper; petri dishes; odd temperature regimens

I hope some of this is useful. Virtually none of the studies were designed to directly answer our real world questions.

Bob

 

[Jack in NB]

Over the years I've tried both approaches - lighted, and dark. There has been no significant difference to either approach with the seeds I've been using.

There has been a faster show with 80 deg temp compared with 70 deg temps in my germination chamber.

What has been interesting is the variation in time for the first sprouts to show between different varieties. Some are off the mark in two to three days, and some take a week. The warmer temps might make a day's difference.

But there doesn't seem to be any difference in long term growth - all progress at more or less the same pace until transplant time.

Having said that, the Iranian Schirazi I grew this year was a couple of inches higher at first haircut time, but after that it kept pace with the others.

Put them all in the ground last night and this morning - along with cutworm bait.

 

[NRustica]

Are these "regular" shop light bulbs or spectrum specific bulbs?

$10 walmart fixtures, and the highest K rating I could get at Lowe's for 32 watt.

 

[skychaser]

Thanks Bob! You da man I'll be doing some reading later tonight. Didn't mean to make you waste your whole afternoon. lol

 

[skychaser]

There has been a faster show with 80 deg temp compared with 70 deg temps in my germination chamber.

What has been interesting is the variation in time for the first sprouts to show between different varieties. Some are off the mark in two to three days, and some take a week. The warmer temps might make a day's difference.

But there doesn't seem to be any difference in long term growth - all progress at more or less the same pace until transplant time.

Yup. I agree. I have observed the same things. I have also transplanted newly sprouted seedlings from 6 packs into 4"x4" pots and let each grow side by side. The 4x4's produce a much bigger plant by transplant time than keeping them in six packs does. But once in the ground things quickly equal out. In 3 weeks time you can't tell a difference. Using the bigger starting pots gained me nothing in the long run. I just used a lot more starting mix than I needed to.

 

[deluxestogie]

I'll be doing some reading later tonight. Didn't mean to make you waste your whole afternoon.

It was not wasted time. Your question made me realize that my recollection of the details was fuzzy. It was helpful for me to sift through it.

FYI, the jstore site is the journal repository that always wants you to pay to see the entire article (more than just the abstract). I discovered today that they now allow mere commoners (not just university affiliated researchers) to register for free reading of entire articles. The catch is that you get a 3 item "bookshelf," and each selected item must remain for 15 days, before you can remove it. So it does allow you to read 6 entire articles per month for free--a huge step up from none. [I registered as an "Independent Researcher," which is true, in its own way.]

The cited article, http://www.jstor.org/discover/10.230...21102303412141, with the tables, requires registering to see. The whole thing is a lot of detailed biochemistry and induction of plant hormones, but it did give me the light duration.

Bob

 

[Gavroche]

Hello,this topic has contradictions with the : for a lighting and counter lighting.But, can we use one lamp or more for the light but also the heat necessary to growth. I think an electric light bulb halogen 2500 K° plus two low-energy light bulbs to 6400 K°. your opinion ?

 

[Chicken]

I'd say do some experimenting....me personally I prefer to use a grow bulb..not sure the Kelvin range numbers..

So lets call it a metal halide light for initial growth..the high pressure sodium Kelvin range bulb is for the fruiting stage of a plant..so me personally I have no use to use a h.p.s. bulb when starting my bacca..just a m.h. bulb

 

[ChinaVoodoo]

Hello,this topic has contradictions with the : for a lighting and counter lighting.But, can we use one lamp or more for the light but also the heat necessary to growth. I think an electric light bulb halogen 2500 K° plus two low-energy light bulbs to 6400 K°. your opinion ?

Growing tobacco requires high Kelvin light for leaf growth. The halogen light is no good. Low Kelvin light is used for flowering / budding.

You also want the bulbs as close to the tobacco leaves as possible to maximize the available light, (if you double the distance, you get one quarter of the light intensity). Therefore, an energy efficient tube is best for starting tobacco plants. They don't get too hot for the little guys like halogen would.

Metal halide is high Kelvin, but the initial monetary investment is high. That's a super bright light, you keep higher above the plants where you can illuminate multiple larger plants. I feel it's overkill for seedlings though.

 

[ChinaVoodoo]

Also, it's more important that the roots are warm. Heating just the plants with a light won't heat the soil nearly as much.

 

[Gavroche]

Ok, so a heating element to your terrarium at the bottom of the earth and a neon lamp "light of day" with reflector is the ideal ?

Traduct by http://www.convertworld.com/

 

[Smokin Harley]

heat mats + full spectrum fluorescent tubes almost touching the plants. I put aluminum foil around the edge to bounce more of the light around and hold heat in. Must have worked well, I ended up with quite a few lbs of quality leaf (I have yet to actually weigh it.)

 

[ChinaVoodoo]

Ok, so a heating element to your terrarium at the bottom of the earth and a neon lamp "light of day" with reflector is the ideal ?

Traduct by http://www.convertworld.com/

The heating element is good. There's actually heating pads, in English they're called a seedling mat. They're the appropriate temperature.

The light is good as long as it's close to the plants. I would suggest from 0.5 to 8cm.

 

[Chicken]

I used heating mats for the first time this past season...and it did make a huge difference...especially if you live in a area that's normally still very cold when it gets time to germinate

 

[LeftyRighty]

I use flourescent lights too, an inch or so above the starts.
But am also a firm believer in good ole sunlight. Any time the afternoon temps are 40's or higher, I set the plants outside, starting with just a half-hour, increasing gradually over a few weeks until outside all day, but move back inside overnight or when temps drop to the 30's. Makes for strong transplants with little transplant shock.