Winter Indoor Growing beyond 50°N

Milan HP · January 2, 2021

As I live relatively far in the north and grow tomatoes over the winter on window sills (no glasshouse), I first faced a lot of problems with providing enough artificial light for my plants. I experimented with LED bulbs, red and blue LED grow lights and luminescent tubes. Daylight in winter that far north is very short (8 hours) and very weak on cloudy, foggy days - just 750lx, so my plants are often fully dependent on the light I give them. I cannot afford arc lamps as they use too much power.

I have come to the conclusion that the minimum light intensity for them to grow properly is 2,500 - 3,000lx for at least 12 hours a day. I also believe that a luminescent tube is a good thing as it provides some UV light and the plants get less harmed by direct sunshine when I put them out onto the balcony.

I wonder if there are any enthusiasts like me who have any experience of using artificial light or growing plants like this. My problem is that I insist on growing indeterminate varieties along with determinate ones, which means that grow boxes are too small for me (and too expensive as well). Can anyone give me any tips or share their experience?

Milan HP

January 2, 2021	#1
Milan HP Tomatovillian™ Join Date: Dec 2017 Location: Ústí nad Labem in the north of the Czech Republic Posts: 332	Winter Indoor Growing beyond 50°N As I live relatively far in the north and grow tomatoes over the winter on window sills (no glasshouse), I first faced a lot of problems with providing enough artificial light for my plants. I experimented with LED bulbs, red and blue LED grow lights and luminescent tubes. Daylight in winter that far north is very short (8 hours) and very weak on cloudy, foggy days - just 750lx, so my plants are often fully dependent on the light I give them. I cannot afford arc lamps as they use too much power. I have come to the conclusion that the minimum light intensity for them to grow properly is 2,500 - 3,000lx for at least 12 hours a day. I also believe that a luminescent tube is a good thing as it provides some UV light and the plants get less harmed by direct sunshine when I put them out onto the balcony. I wonder if there are any enthusiasts like me who have any experience of using artificial light or growing plants like this. My problem is that I insist on growing indeterminate varieties along with determinate ones, which means that grow boxes are too small for me (and too expensive as well). Can anyone give me any tips or share their experience? Milan HP