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I hope everyone had a Happy Easter!

Question: I’m trying to start lettuce from seed this year, but am having trouble getting any germination. The seed packets are marked 12/2024, and I’ve tried a couple different “seed starter” media. Planting depth is 1/8”, as per some of the seed packets’ instructions and common web recommendations. Soil temperature varies wildly at that depth, as these are in starter containers, outdoors: Soil temp. has been between 35° F on a few cold nights, and near 80° F on warm days. (I do cover the containers on cold nights, as air temp. has been as low as 31° F a few days ago.) AVERAGE soil temperature would be ~60° F. The seed starter media is kept damp but not “wet”. Watering is from the bottom.

Is the soil temperature variance the problem?

I’ve seen a FEW recommendations for lettuce seeds to be right on the surface / not buried at all. ???

Would germination be better if the seeds were on the surface and covered with very light transparent plastic like Saran Wrap for moisture retention? (Obviously I’d have to remove the clear plastic soon after the sprouts came up.)

TYPICALLY, what % of lettuce seeds germinate under good conditions?

Thoughts?

Thanks!

I started mine in seed trays ad did cover them with plastic wrap until they started germinating. I didn’t have trouble with those but with the parsley and thyme, and lavender, they’ve been bears.

One thought I had about covering seeds outside is to use an old under the bed box bottom. They could be used lie mini greenhouses and propped up during the day but let down at night. I don’t know if that would help with germination of lettuce, though. I thought it might only add a growing zone to the seeds under it.

I think I've just come to the realization that seeds can be sown a little deeper in starting mix or potting soil than what the packet says. The depth given is for direct sowing I believe and soil is harder to push through than starting mix.

One of the more experienced growers here can correct me if I'm wrong about being able to sow deeper in fluffy mix.

Noticed it when starting bok choy and Asian greens. They both tend to put out multiple shoots right at ground level as so;

Mine have up to an inch of single stem before they split like below but longer and the longest ones are wanting to flop/lay over. I'm thinking if I had sown them twice as deep as what the packet says, they wouldn't be like that.

I always top water until they sprout and use a humidity dome to prevent that top of the mix from drying out.

Wildly swinging temperatures will have an effect. I set my heat mats for 76 for cool weather crops and just bumped it up to 82 for peppers/maters. As soon as they all sprout, I'll turn it down to 70 and pull the humidity dome off. Once they have true leaves, I'll turn the mats off unless it's a really cold night because my seed starting room is unheated.

I would bring your containers/trays indoors, top water and cover with something to prevent drying. As soon as most all of them sprout, pull that cover off. If you don't have grow lights, as soon as they sprout, bring them outside and then only cover on cold nights.

I always get 90% or more germination if I do everything right.

It's kinda crazy how cool weather crop seeds need to be warm to sprout but a few weeks later, the plants can handle cold just fine. Must be why Spring seems to come in a sudden burst when conditions become just right.