Cuttings in transparent pots

That sounds good Marley. I have had teriffic fun with my light box. Its great for cuttings and early seeds. And also a source of interest during the cold dark winter days, as I currently have small plants in there flowering their heads off.



The key is getting the right light level which must be high, but not so high as to cost a bomb to run. My lightbox is shown above. Its slightly larger than a growbag tray, which is 39" by 15.5", to leave some finger room. I used 3 three feet long fluorescent tubes of 30 watts each. ie 90 watts. This gives a light level of 10,000 lux, at the top of the plants, as measured by a light meter. This is an ideal level of light. Its not that high compared to a summer's day where the light could be anything up to 50,000 lux, but plants saturate at about 20,000 lux and can't utilise any extra light. Also the light is at this level for 14 hours a day (run off a time switch) as opposed to daylight which varies over the day. Your proposed light level would be almost identical in relation to the area.

To me the ideal bulb is a fluorescent tube, as its slightly more efficient than spiral bulbs and more uniform. You can get the plants closer to the light as well, unless you put the longlife bulbs sideways. The light level will fall off with the distance from the bulb, so its a good idea to have the plants as close to the light as possible. For that reason I put the lights on a suspended ceiling so that I can raise or lower them.

However your long life bulbs will be very close in light output. And your proposed set up sounds very good. I am sure you know that you also need to have all surfaces either reflective or painted white to reflect the lost light back onto the plants. If you use 60 watts and a timeswitch it shouldn't cost you much more than £3 a month to run.

 

Sounds good Marley. I look forward to some pics and feedback.

I did a little measurement of the light levels in my box last night with the following results.

0---40.0---40.0
1---18.0---13.3
2---14.0----8.0
3---12.5----5.7
4---11.0----4.4
5----9.5----3.6
6----7.8----3.1

The first column is the distance below the fluorescent tube in inches. Add an extra half inch to the centre of the tube.
The second column is the actual light level in lux
The third column is what I calculate the light level in lux would have been without any reflective surfaces. I am assuming that all the light comes from the centre of the tube which is one inch in diameter, and using the inverse law. Light from a point source follows an inverse square law, but from a long tube follows a simple inverse law.

You can see that the actual light levels in the second column fall off with distance, but not as much as they would (if my calculations are correct) without any reflective surfaces reflecting lost light back into the box.