Greenhouse Grow During Winter Northern California

I have been doing greenhouse grows beside my outdoor and indoor projects for the last couple of years and thinking of trying one during the winter time. So my question is how much supplemental lighting to use. Here is what I am thinking.
On cold cloudy days runs lights in the greenhouse to give them their 18 hrs of light. On sunny days only turn lights on to extend the lighting period to 18 hrs.
Once I flip to 12 /12 kinda do the same thing and of course I will be blacking it out so as not to light up my back yard after dark or early morning when it's still dark.
I was thinking of running 2 600 watt HPS small open hoods in there for the lighting. Greenhouse size is 8' wide 7' high and 15' long. My canopy in there is roughly 5' wide by 12' long.

Thoughts and recommendations would be most helpful. Thanks in advance.

growing in winter is a whole new ball game for me

as above will work. but you gotta account for cold, even strain

I prefer a 100% indica, easier to handle the cold

double the soil amount as it is good insulation

then theirs mold, that you have to learn to fight

everyday, as it rides in with the high humidity

thanks to cold air and hot lights

when the plants srart to fail...many will

look to fish tank heaters insert to the soil

old/used electric blankets can work

but really too cold for me

some guys have bred strains that do only grow in the cold

but these are years ahead for now

good luck

Hey and thanks for the reply I am northern California so not too terribly worried about the cold. Keep the greenhouse warm is also not much of the concern.I am more concerned with having enough supplemental lighting to get a good yield in there. I am gonna shoot for the two 600 watt hps with Eye Hortilux bulbs as I love these bulbs and pretty much all I run. So I will keep everyone posted. Fingers crossed

I do greenhouse grows in winter out in the rainforest here in Australia. I just plant the seeds and let them grow .they only get between 18 and 30 inches tall. But if your using lights as well then your plants should get big. Just try lots of different strains as you willbquickly realize that some strains really hate winter

Do you have your plants going already? Last year I dropped seeds December 1 and than again a week later. I vegged until Jan 19th, then put them outdoors {here in NW Florida}. Some of them had to be picked early due to reveg issues. So you need to get some seeds in soil, or pick up some clones soon.

As far as lights, I would only use them to veg. And I might just use the gas lantern method, and burn them for one hour at midnight every night. Strains vary on the flower/veg switch, so you need to think about that. It's best to do "early" stuff in winter to help combat the threat of re-veg. But I would have them on natural light hours no later than the 1st week of January.

Good luck.

How did this ever turn out? I’m in SoCal I was thinking of something similar but I was thinking of running 3x double ended and putting them at 750w my greenhouse is 12x30

roksonix said:

How did this ever turn out? I’m in SoCal I was thinking of something similar but I was thinking of running 3x double ended and putting them at 750w my greenhouse is 12x30

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SoCal has mountain valley resource on the Santa Ysabel reservation. They grow greenhouse year round using light depo and supplemental lighting.