Grow Light germination ?

Thanks Peter , I have ordered a vent for the top cover to cool things down a touch. I will leave the front cover off until I can get this fitted.
My first impression of grow boxes is pretty good so far. The couple of plants I have in it seem to be thriving. Its difficult to know how well they are doing unless you can do back to back tests with a windowsill set up.
It doesn't look very pretty , but it seems like it will do a good job

 

The old way of measuring if the soil in the Veg Plot was warm enough to start sowing seeds in Spring was to drop your trousers and put your bum on the surface. If you jumped back up again in shock then it wasn't ready yet! (Of course that old wives tale may be completely apocryphal ...)

 

Kristen , I can see all of GC doing a mass early morning moon to test this theory tomorrow :D

 

Kristen - you soft southerners wouldn't start sowing till July. Us is Yorkshire would start in February and all the seedlings would die.

 

I think you are both showing off !!

 

How soon do you think that you'd start if your "man bits" just happened to land on a wee thistle (or nettle)!!!!!:OUCH::OUCH::OUCH:

(been watching this thread with interest and this is the first contribution I could offer :o:o)

 

Got a delivery this morning - a 2nd T5 grow lamp (as in post # 21) above. I've now got the greenhouse heating on and intend moving the whole operation there. In addition to the lamps I have 2 Sankey Plantmaster 40w variable thermostatic control propagators that can either be underneath a lamp or outside. Each light box or propagator can take forty 70 x 70mm pots or ninety six cells from 40x tray inserts and I'm going to give them shifts under the lights to increase the amount of plants benefiting from them.

 

Discussing questions on lighting is kind of like answering the question, "how long is a piece of string" because it all depends on what we are growing, where we are growing it and how many plants are absorbing the light. What we need to consider is whether we really need those expensive T5 tubes, fluorescent fittings, reflectors and grow tent: The minimum brightness per square foot is 2000 lumens and the optimum probably 5000 lumens which can be attained with the use of a simple reflector and daylight energy-saving CFL bulbs. For example my standby indoor propagator is a Sankey Growarm 100 and the light source is a 45W 6400K daylight CFL (blue spectrum) in a cheap angle-poise desk lamp the shade of which almost touches the lid of the propagator which acts as a diffuser! Where T5 tubes score is that they have more brightness and less heat.

The major problem with artificial light as opposed to natural diffused light is that the light which is usable by plants falls off dramatically after a few inches and so the light has to be as close to the plants as possible without burning and/or bleaching the leaves. But plants get taller which means the light source has to be raised which in turn means that the top leaves get the optimal light while the bottom leaves get less. In an ideal set-up therefore we would need not only top lighting but also side lighting.

Lastly the crucial aspect of the light spectrum can be seen in the growing of African Violets: They do better when left in the same place all the time and only turned but never moved, i.e. on a bright but shaded windowsill.That's because they can get both light spectrum - morning (red) through daylight (blue) to evening (red again). The corresponding Kelvin rating is 6400K for blue and 2700K for red. In T5 tubes there is a third option in purple full spectrum but these also produce a small amount of ultra violet light.

Incidentally the use of daylight 5500K to 6400K CFL bulbs in the home is a cure for winter blues depression and also benefits house-plants with a bit of extra light.

Hope this helps. Sorry for my late reply, I only just signed up today.

 

As an alternative, where you have plants of different heights, or taller plants which need light to the bottom leaves too, is a Metal Halide lamp which has good canopy penetration (compared to fluorescent tubes)

It has downsides of course, and tubes will be better (cheaper / less heat etc) for seedlings of even height.

 

Jeez ! Calculus and thermodynamics was easier than sticking a light bulb over a Marigold :D

 

Forgot to come back with a pic of my double T5 lamp illuminated growlamp box now located at the 'dark end' of my greenhouse. Takes 2 propagators + some spare space, Mylar for the sides, white polythene on the base, lights on adjustable hangers, and easily capable of extended in height. Unlike most growlight users I used aluminium tape for my joints. All those toms & chillies are going to be on 8 hr shifts as soon as I pot them up.

 

Mine is located at the 'tidy' end of my shed.

 

I reckon you knew what I meant by the 'dark end' of my greenhouse, and why I only showed the inside of the box!

 

Interesting arrangement for adjusting the height of the "lights" Pretty much exactly what I do - "Need to raise these, what's to hand? A=Flower pots!!"