Id like to start saving seed from my best lettuce plants.
I can't afford to tie up a bed iny garden for an extra month in summer while my lettuce bolts, and while fall lettuce is very productive here, it is killed by freezing before seeds can form.
I think the solution is to save only one or two bolting plants of each desired type of lettuce, pulling the rest. I can afford space for that.
How long do you find it takes lettuce to go from "starting to bolt" to "ready to collect and store seed"?
How many seeds (or ounces, or grams) do you typically get from each lettuce plant?
Lettuce can be really slow to bolt in my climate, depending on variety but also on temperature I think.
For example, I have two plants in my greenhouse right now that were started last winter - I mean, over a year ago. They only started to bolt in late fall and in the actual winter cold - surprisingly survived. At this point there are a lot of buds on both plants, which have been forming steadily in cold and swinging temperatures (hot sunny days) but none have opened yet. And the leaves are a mess, so they need some care and nourishment to take it to the next stage.
The amount of seed per plant depends on how big and well nourished the plant is. In small or average sized containers, I can get enough seed to meet my needs and share a few packets from a couple of plants.
But a friend of mine went for the big crop one year with a well nourished single plant in the ground in her greenhouse - the flower stalks were over 6 ft tall (cw a foot or two on my small plants). You can definitely get a lot of flowering biomass from a single plant, if you nourish it well and give it enough room. The down side of more room and nutrients is that the plant will take longer to go to seed, while growing up these big flower stalks but not necessarily opening flowers in a hurry. Speaking of a cool climate situation, where degree days are limiting. I'm tempted to pot up my bolted lettuces, which are in quite a small container, since spring is coming and they have lots of time to flower. If season end was the issue, I might try fertilizing with bone meal and keeping them in a smaller pot. There would be some additional growth from the N with pot size to limit root growth, then the availability of plenty of P will push them to flower.
Just to give you a harvest estimate independent of plant size, expect a dozen seeds from each well pollinated swollen and matured bud. The range for me has been about 6 to 20 per bud, so dozen is around average. I'm going to SWAG that it takes at least a month from opening the first flower to having a ripe bud ready to harvest - YMMV depending on degree days though. You can harvest the buds as they reach maturity and keep the plant going until you have enough.
It's quite easy to get enough seeds for home use, as long as they bolt early enough.
I've had a few problems - last year my lettuce plants got some black fungus crap on the flower stalks, and although I collected some mature seeds I wouldn't even try sowing them without some kind of antifungal treatment. I'm looking into garlic juice as a way to treat those and my tomato seeds as well, for the funky year. Most years, lettuce seed has been easy.