https://www.canr.msu.edu/news/...

But I'm still confused. I am trying to decide how many hours per day to set my indoor lights for my lettuce plants, thinking that I should keep the hours on the short side because long day might be the cause of them bolting. I may already be in trouble though, because they've been outside feeling temperature swings and THAT might have already set them on the path to bolt.

Don't feel bad. Covering potato plants, long vs. short day onions and everbearing (which really aren't) strawberries have been explained to me umpteen times and I still don't get it!

My lettuce is still OK on about 10 hours of light. for about 3 weeks now? Fertilizing and repotting so they have room to spread also helped, especially the butterhead one that wants to lay out. The Jericho romaine can go up.

Still not bolted.. but not growing very fast either. But I havent tried all that hard; maybe can fertilize again tomorrow. Darn aphids.

Bolting starts when the heat goes up, also your Spring Daylight hours have to be above 11 before they get their feet under them. Heat amounts? Well, I can be 90* in March, and stuff bolts, but I am then just at 11 hours, so think of it like tomatoes, the temps sing to those flowers more than the light hours.

Yes, ten hours of light is not enough for growth
https://www.highmowingseeds.co...

Very informative article - I love the seed companies that provide us with so much growing information!

Where I am we have just recently (on Feb. 8th) exited the "Persephone period" - the days when we have less than 10 hours of daylight. And considering we have had very few sunny days during that time this winter, it's no wonder people get depressed.

However, the way I understand this, 10 hours of daylight is enough for growth, but not for flowering.

Fall planted tyfon, tatsoi and collards are all bolting now.
Those lettuce I started the thread with, I don't remember getting very far with. Me and lettuce,

Lettuce is always there and gone unless it gets so old it turns bitter for some of the tougher lettuces...

Sally, what seems to go wrong with your lettuce? This is a photo of some that I grew indoors last year (right now I have some tiny seedlings started).

Weedwhacker, your last year's lettuce looked great! What variety was that?
I have just started my seeds, set grow lights for 14 hr days, about what the Almanac predicts for first of May.

love2garden2 said: Weedwhacker, your last year's lettuce looked great! What variety was that?
I have just started my seeds, set grow lights for 14 hr days, about what the Almanac predicts for first of May.

"Truchas" - it turns red when grown outside but never developed much color under my lights; it still tasted good, though!

Bolting -- That is what I do if Sharon comes home unexpectedly and I have one of the side doors open so the cats can go outside in the winter.