13 hours ago, Midlife said:
I grow tomatoes each spring/summer from 3” potted plants - one plant each in a 14” container here in SoCal. The only place I have for them gets almost no direct sun. This year the plants have grown to almost 3’ tall in around 60 days and all have a lot of flowers but no tomatoes so far. My Googling has made me conclude it’s the lack of direct sunlight, but if they can be grown in a greenhouse, I’m wondering if it’s something else. A friend bought a 3” plant that already has a few tomatoes on it (one is maybe 2” already) but those plants get direct sun. Do I just need more patience?
Tomatoes are a high light crop - they need like 25 to up to 50 mol/day of light which translates to either several hours of full sun per day or like 20 hours of strong shade per day. Most commercial greenhouses have much more light than a shaded area would get, plus, during the short day season, they would have supplemental lighting fill in the gap. It is not difficult at all to get 50 mol/day in a greenhouse - heck, I can even get it indoors using a really strong LED grow light. Years ago, I grew a fantastic Goose Creek heirloom tomato plant in my southern facing windowsill using supplemental LED lighting. Since it was indoors, I had to hand pollinate, but that doesn't take a lot of time for 1 plant and I had a LOT of tomatoes. Probably 3-4 tomatoes every day for 6 months at least (Goose Creek (as well as most heirlooms and greenhouse hybrids) is indeterminate which means it will keep growing and fruiting for about a year as opposed to a determinate tomato which fruits all at once and then dies at the end of the season).
