Greenhouse lights

No I won't be growing a high value crop.ha ha.
If you can answer I shall be having the green house heated to 20c and I was going to just extend the day light hours by starting the lights at 6am ish off at 9 ish back on at 4 pm ish till 7pm ish and I want to grow chillies.

 

Heating a greenhouse to 20C will cost both arms and at least 4 legs!

I reckon you would be better off to build/buy a light-box indoors and grow them in there, indoors.

Worth looking at a Grow Tent from the Hydroponic shops - designed for high value crops but all joking apart it is well worth reading up about growing under lights on the Cannabis forums - those guys have got it down to a fine art.

Growing tent:

e.g. http://3ch.co.uk/accessories/grow-tents/grow-cube-pro-tent-241/prod_1558.html

 

Can I start again,I've a 8x6 wooden green house and now have installed a 600w sodium grow light,I'm going heat the greenhouse with a electric 2 kw blower can I turn on the lights at 6am ish and off at 9am ish leave the heater on and then turn the lights on about 4 ish at off about 7pm ish
To supplement the natural light through winter to grow chilli and other crops.
Sorry to say again I'm not concerned about the cost.

 

You can, but if the day is grey I don't think you will get the effect you are looking for.

Check what your light will tolerate, but most of that type will not tolerate the lamp being on for "short" periods, and certainly not being turned on/off at short intervals. I expect that 3 hours is fine, but you might find that 3 hours twice a day shortens the bulb life more quickly than 6 hours once a day. Either way, you should be replacing the bulb after 1,000 hours (which may only be 3 months) as the "light power" will have dropped off considerably (worth getting a light meter so you can check it).

I presume you already have plants and want them to "fruit", rather than wanting to grow them (because AFAIK Sodium is in that light spectrum, rather than the vegetative spectrum)

I think you would be better to light them overnight for 12 hours, but allowing a period of dark (assuming that chillies need that, they might not). Benefit of this is that any heat from the light will be at the time that the temperature is coldest, so will help with heating (your 2kw heater may not cope on its own when outside temperature falls to, say, -10C) If it then happens that you get a bright day the plants will benefit further from that. No sense running the lights during the day (unless you hook them up to a light sensor) as some days will be bright, and some not, and I think that just running them at the ends of the day may mean that the plants shut down during the day if it is dreary, rather than going full steam ahead (hence 12 hours continuous, rather than 3 hours twice a day). Either way Mid Winter has 90% less light "power" then Mid Summer.

We all spend money on our hobbies, so not for me to say what you should spend yours on, but my own personal view is that it is environmentally irresponsible to heat a building of such poor insulation, so warm, when there are other better ways of achieving the growth that you want.

Couple of thing to consider:

what happens if you get a power cut (or some other equipment malfunction).

Pay attention to bugs - they will have a field day with good heat and strong light. I made that mistake the first time I grew plants under lights because I assumed that, as it was winter, the bugs would be hibernating - they didn't :(

 

Yes I might just leave them on for 14 hours a day.

 

Kristen has made a good point regarding indoor greenhouses, or grow tents. I purchased two on eBay for about seventy dollars each, delivered. They have supports for lights and several openings for ventilation. The mean temperature in the basement is about sixty degrees F and the lights provide sufficient heat to grow tomatoes, cucumbers, peppers or whatever I want. I have a greenhouse, but really prefer growing indoors where I have complete control of the environment. To tell the truth, it is much easier indoors than in the greenhouse. I use a sterile media, coir and perlite, and feed the plants with inexpensive nutrients. Without soil I have never seen an insect in any of my plants indoors. Last year it was tomatoes and cucumbers, this year it will be tomatoes and peppers, and, of course lettuce, swiss chard and beet greens.

 

I'm afraid that's not a option for me.

 

The climate where I am prohibits gardening during the winter, so I garden indoors during our long cold winters to keep my sanity. Roy, do those lights attract a lot of insects?

 

Only just fired it up for the photo so I don't know yet all new to me.im having a shed delivered tomorrow and the electrician is going to wire it all up in the next few days. I might get a 600w MH to go along side the sodium.The sodium has extra blue so should be alright in the veggie state but it does look very red..it has dimable ballast so I can turn it up from 250 w to 660 w.

 

Well good luck with them. If they don't work all that well in the dead of winter they will SURELY be fantastic in the spring and late autumn.

 

You can see the effect of "generous" light on the Cannas I sowed from seed under lights earier in the thread:
http://gardenerscorner.co.uk/forum/threads/greenhouse-lights.54086/#post-722358

Run them at night though, you might as well have whatever sunlight there is, for free, during the day.

 

P.S. Beware that you might need a "contactor" for your timer - high powered MH lamps will burn out an ordinary timer and I expect Sodium is the same.

Not come across that before, I thought Sodium gave a very narrow band yellow light?

You might find that the dimmer uses no less electricity - I don't understand the details, but I think it has something to do with how the dimmer "clips" the sine wave. If that's the case you'd be better off running it on full power as it will make no difference to cost, and the plants will prefer it

 

I believe modern dimmers "chop up" the sine wave, essentially shutting off the current to the bulb each time the current changes direction, thus reducing power to the bulb. This may play havoc with your bulb life, but I am not sure, as I run my 400 watt units full on.

 

Expecting a knock on the door from Plod,the police Helicopter was hovering directly overhead looking at my bright greenhouse.Weeds I'm not into.ha ha