Lovely! I planted lettuce seed out a couple of weeks ago - beautiful warm day - then it turned back into winter (29 degrees for several nights and a deluge of rain) and I fear the seeds won't germinate. I am waiting for consistent warmer days and nights to determine if I need to replant. Weird weather for South Carolina.

If you want to harvest some seed from your lettuce, I would let it grow back, flower, and then harvest the seeds. I find that fresh lettuce seeds germinate the best. So even if you are "flush" with seeds today, the germination rate may decrease as your existing seed ages.....so consider letting a head or two grow out. I have cropped some lettuce and let it come back, but if your temps are already pushing 80+, I wouldn't expect the same results as your initial harvest. If your space is limited, I would let one plant go as an experiment and think about some heat-tolerant varieties. Since you are growing your lettuces in a container, you might be able to move them around so that they get partial sunlight or are shaded in the afternoon. That may help some. In any case, harvesting your own lettuce seed is fun and it only takes a few plants to produce a lot of seed. Good luck and keep us updated!

Enjoyed the links posted here. Here's my own 2 cents on this. I do all the seeding for a CSA (about 70 boxes per week), sow about 300 lettuce seeds a week for 7 months straight. The first and second year made many mistakes and got poor germination. Putting lettuce trays on heat mats did reduce greatly the germination rate. Putting the trays in a unheated hoop house also didn't work, it got too hot during the day. Now we just leave them outside. In spring gets down to 45F at night, maybe 55F during day. We use automatic overhead sprinklers, so the trays get over watered every day. Our seedling table must provide water for all the seedlings so must water enough for the largest plants. To prevent damping off, use a 1:1 perlite:peat mix (Black Gold seedling mix) with some sifted compost included 4:1 mix:compost. The overall mix is light and airy. A coir based mix didn't work, stayed too wet. Use only solid fertilizers, liquid ones get washed away with the overwatering. For the mix, I add in crabshell meal (Eliot Coleman recommendation), greensand, and soft phosphate. When I added in bloodmeal or fish meal to the mix I got damping off. To much available nitrogen. When the seedlings are about an inch tall, I sprinkle a mixture of bloodmeal and sifted compost over them. This gives them the needed nitrogen and once an inch high, I've never had any damping off. To save time I never tap the seeds into the mix. After filling the tray with mix, just drop/bang the tray against the table 4 times to get the mix to settle to a good firmness. Put the seeds on top and add a layer of fine vermiculite and overhead water. The fine vermiculite layer noticeably increased our germination rate on all seeds. Keeps the top moist and more importantly protects an emerged seedling from fungus. The vermiculite is sterile.

Thanks, Art. I took the advice after see the following posted on a couple of hydroponic sites: "Do I need to soak my Rapid Rooter plugs? Answer: For optimal results soak Rapid Rooter plugs in pure water with a light blooming formula (200ppm or 0.4mS), then place back in tray and follow procedure for cuttings or sees. " And then I used this online concentration calculator: http://www.cleavebooks.co.uk/scol/ccconc.htm Not sure if i got it right, but thankfully there must be a margin of error because my seedlings are thriving. It's been only four days, and the lettuce is just over a half-inch tall, and I can see the spinach seeds cracking open. One spinach is even showing green.