Artificial lighting

[veggiechicken]

I have some seedlings of rocket and parsley in the kitchen which were getting leggy and visibly growing towards the light each day. Today, as it got dark outside I moved them under the light from a low energy bulb in an Anglepoise lamp (which I use for lighting the keyboard. All the seedlings have now changed direction and are facing towards the light.
Would this light improve the growth rate of winter sown tomatoes?
What does the team think?

[solway cropper]

This growth towards the light (phototropism) is the natural inclination of most plants and may well result in improved growth, but at what cost? Weak, leggy plants are not really going to be able to cope well with the rigours of life in colder conditions. Personally I'd rather have short strong plants but that's just me.

[snohare]

The reason your plants are leggy is that they are not getting enough "oomph" from the light they receive. In nature that would mean they are shaded out by a competitor, so they try to grow faster. But actually, it is because the light they receive is lacking specific wavelengths, and therefore they cannot make enough energy.
The reason you can grow some plants indoors and not others is that there are three different biochemical pathways by which plants can achieve photosynthesis: one is more suitable to hot climates, so tropical plants use it, one needs wavelengths often filtered out by glass, and another which many houseplants use, is less fussy.
If you want to make a difference, try either a full spectrum lamp, or maybe an old fashioned halogen bulb desklamp. The bulbs in them pack a fair punch, in fact they were associated with an increased risk of skin cancer in folk who used them a lot, due to the amount of white light they emitted.
For some plants, I'd guess there's a chance they would be a good bodge job for short whiles at least. But meantime, with a low energy bulb, I think all you are doing is dribbling water just out of reach of a man dying of thirst...in a different direction.

[veggiechicken]

Thank you both for your erudite advice. I guess I knew it couldn't really work or else everyone would be doing it!
I felt sorry for my poor little seedlings, in the dark for so many hours of the day. Somehow, I didn't expect them to respond to the light of an ordinary indoor light bulb. I don't intend doing the job properly with professional growing lights but I'll let them share my Anglepoise for a few more days and see whether they appreciate it! Next time I sow a few seeds indoors I'll do a test, comparing some on the windowsill for the whole of their indoor life with some that share my light!
And, in reply to Snohare, I have to say that, despite growing up in the gloom. I have not grown "leggy" - I wish!!!

[Dead Dogs]

Hi VC,

I had the same problem with seedlings back in January and spent a little time looking into grow lights. I'm assuming your low energy bulb is a fluorescent type, these come with differenet spectra. A bulb marketed as 'warm' has a red shifted spectrum, where as a 'cool' is shifted to the blue. In my research I found that red light encourage plants to flower and blue stimulates leaf groth. The other requirement is intensity, how many photon (packets of energy) reach the plant. Snohare is right when suggesting using a halogen bulb. They produce a lot of blue light, even into the UV, but also produce a lot of heat and uses more power than a fluorescent bulb.
I end up buying a blue LED grow light (225 LEDs) which worked very well for my seedlings

[veggiechicken]

Thanks for your advice DD. If I should ever take winter growing seriously I'll buy one of those LED lights. Meanwhile, I've put the seedlings in the greenhouse as it it so unseasonably mild here. The indoor coriander has also just started germinating so that may well be joining the rocket and parsley in the greenhouse in a day or two!