Growing seedlings under artificial light

[loeb]

I just wonder .. I have an aquarium that i wanted to dry off and use as a mini glass-house to grow hosta seedlings. Light in that thing is very strong - 10 000 Kelvin.[26Watt only] That is one of the reasons I don't like to use that as aquarium - it's pain for my eyes to watch fishes in that light.. But water plants loved that cool light [white and blue] and flowered under it.

Now my questions are:
-does potatoes needs night period? hosta seedlings don't..
-that "hotness" of light -could it harm potatoe seedlings?
-what can happen [would they flower, or set little spuds, or just grow? how big they can grow under it?]
-do i need make them some transition to a normal daylight?

The idea was to grow seedlings trough the winter, so I could get a strong plants to put out in garden, or maybe even a little spuds.. But I have no idea how that experiment will work Any advice would be very precious..

[wingnut]

Flourescents work great to start seedlings. Keep them within 1"-2" of the plant tops. turning plants to 9 hrs should initiate tuberization.

[Tom Wagner]

The questions are good. My answers may not be. If one wants lots of tiny tubers of a diverse coloring...I might edit this a bit more. Anyway....


Now my questions are:

-does potatoes needs night period? hosta seedlings don't..

Potatoes as meristem tissue or as seedling TPS plants do quite well without a dark period. If you want tubers ....the night time is necessary for the plant to rest so to speak....and move that energy to the tubers. 24 hours of light is good for vegetative growth and for making cuttings. Tuberosum/tetraploid..do well with 18 hours of light...diploids 12 hours or less.

-that "hotness" of light -could it harm potato seedlings?

I would place a thermometer near the top canopy of leaves....a constant high temp in the the eighties would be for vegetative growth again and not for tuber formation. The resting period of darkness would be cooler and that would be best for wanting tubers...

Ideal temps? Maybe 72 F. during the light period and 60 F during the dark period. But this is just my common sense showing...try what you want and let us know how they do.

-

what can happen [would they flower, or set little spuds, or just grow? how big they can grow under it?]

Experience will tell...but the plants will flower if they have a fair amount of soil to grow in ...the size of pot will directly affect the size of plant...if you want smaller plants...use smaller pots. The potatoes will tuberize in small containers and will reach senescence earlier. A large amount of soil media may grow a vine too large for the aquarium. I would not spend much time trying to get potatoes to flower unless you have greenhouse size capacity.

-do i need make them some transition
to a normal daylight?

Not unless you are taking them outdoors and that will require a bit of hardening off with increasing amounts of outdoor light starting with short amounts of direct light or best...diffused light. If you are transplanting to larger pots near windows...not to worry about the transition.

The idea was to grow seedlings trough the winter, so I could get a strong plants to put out in garden, or maybe even a little spuds.. But I have no idea how that experiment will work Any advice would be very precious.

I doubt if the plant/vines would last until Spring...too many months. The best bet is to get some mini tubers to form...harden off the plants with reduced watering as the leaves turn yellow and harvest the small tubers...hoping you have three months to break dormancy in the tubers and plant outdoors in the regular season for optimum performance.
TPS seedlings need only 12 to 16 weeks to form tubers of good quality to be provided...and the container could be as small as one inch square up to maybe four inches in diameter. This system would favor early varieties and not for 150/180 day potatoes.

[loeb]

Aswers are great! So many good informations. If they can set mini tubers under those lights, that would be my goal. It's much easier for me to plant little tubers in garden, than to watch for delicate seedlings in a house with a cat and some evil mice eating the seedlings while cat sleeps [2012 spring case :>] In aquarium they will be safe, they don't need to flower. They may flower in garden later, growing from spuds. I was thinking about planting them in a little plastic containers, those are a little more that an inch in diameter and maybe 2 inches deep. I am not growing very late varietes, because I'm not sure they are good for my climate. I will see how it will work, 12-16 weeks to form tubers is a great information, so I will now when to plant.

Next questions coming:
- if I will get those little tubers, I guess they need some dormancy period to start growing in garden. How long should that period be, and how to take care of them [I know they can't dry off, but maybe keeping them in fridge would be a good idea? 5*Celsius cold, it works for me when I'm preparing some other seeds to planting]

-if the total time for a seedling growth is lets say 16 weeks to set tubers ready to harvest, but they need night to start setting tubers, when I should make them "night"? I'm not sure I can tell after a vegetative growth when this time came. So, maybe that could have some time frames.. lets say 8-9 weeks since sprouting? or something like this?

-what night would be better for them - artificial one, or natural one? nights in winter are long. I can do that 3 ways :
1. Just set timer in aquarium to glow the light for 12 hours, and then just turn it off.
2. As above, just placing aquarium in a way that natural light reaches it too; then setting timer in a way that gives plants a natural "morning" of "evening" - much less energy in this light will come to plants so maybe that will help to set tubers [is there any difference?]
3. After period of vegetative growth I'll just moving plants to a windowsill [south window, I'm not sure if there will be enough light]
4. Point 2and 4 combo - growing like in 2, but giving them a "finish" on a windowsill, maybe this will make plants want to die-off, so more natural finish [only my guess, it may be totally stupid idea]

If one wants lots of tiny tubers of a diverse coloring...I might edit this a bit more.

Please tell us a bit more I love to hear everything you can tell me.

[Cole_Robbie]

Light in that thing is very strong - 10 000 Kelvin.[26Watt only]

Wait a minute, you never said what type of light bulb it is. Is it fluorescent?

I'm asking just to make sure you don't use a halogen light, because the spectrum is wrong. If it's metal halide, (which is blue light), that is actually even better than a flourescent, as long as you can control the greater level of heat that it puts out. I'm guessing you have a metal halide, since you said it was bright, blue, and plants liked it.

High pressure sodium light, which is red/yellow in color, will also work, but tends to make leggy seedlings. LED lights are the newest thing. They work ok, but they are ridiculously expensive.

[loeb]

This is not halogen, it's fluorescent bicolor white/blue lamp. Ready to use LEDs are expensive here too, but I know that some people make some DIY LED lights, and that is more economical. But It's hard to compose good spectrum of pure LED. Anyway, mine is not LED. And I guess not metal halide either, just bicolor fluorescent.

[Crandrew]

Folks, unless you are flowering there is NO NEED for anything but some basic fluorescent or at most some T5 or High Power T5 fluorescent lights. the MH and HPS should ONLY be used if you are doing some serious veg and flower cycles. LED is too expensive for the benefits right now.

I mean you can even flower under T5 but its not ideal.

[loeb]

I don't want to buy anything special, I just want to use what I have If they will set tubers it's good enough for me. I wonder how tomatoes would grow there..

[NGGrant]

I use MH, t5ho with individual reflectors and an array of 3w Cree LEDs to grow corals in various fish tanks, I get the best growth and most evenly spread light from T5s.
T5 with individual Reflectors and actively cooled ballast are at least as good as the halide system. I am going to build a cheap system for starting Veggies indoors this winter.

"Bicolor florescent" could be various things ( t5, power compact,T8 T12) and those different iterations would all provide different results. For veggies you will need a yellow/ red spectrum not a cool white light.

[loeb]

I guess mine is a power compact, the whole thing [tank + stuff] was cheap. I know that red spectrum would be better, but I have this cool thing, and it would be good to make it usable to something I can add some red leds if this cool light won't work alone. We will see.

[wmontanez]

I grew potatoes under lights during my winter. I only have 2 T8 6500K flourescent lights. Total time for my potato was 5 months to get tubers. Mine were pull-sprouts but I also grow TPS under lights. I typically set my TPS plants out after 8 to 12 weeks but if you grow TPS in a small container it will trigger tuber formation after 3 months under 12hrs of light.

Read the following post for a timeline.
http://tomatoville.com/showthread.php?t=18847

TPS seedlings with pictures of what to expect.
http://tomatoville.com/showthread.php?t=17483

[loeb]

Thank you wmontanez/Wendy It's really helping. I was thinking about one seed per cell but now maybe I should do 2.. But I see that they are not so extremly big when setting tubers, good news for me.

[NGGrant]

I have some TPS and Lilly seed I plan on growing them under some old GE6500k bulbs. Thanks for the photoperiod reccomendations.

Loeb the PC bulb should be fine, if the bulb dies get a 3500k bulb

[Crandrew]

Originally Posted by loeb

I don't want to buy anything special, I just want to use what I have If they will set tubers it's good enough for me. I wonder how tomatoes would grow there..

You should try it I bought three varieties of dwarf tomato project seeds to try in the fall