My XDH told me the best depth to plant seeds at is 1.5 times the width of the seed. Me being me immediately thought I have never seen a plant or tree naturally do that to ensure their seeds grow, so if nature doesn't do it that way, who says it's the "best" or "right" way? I remember my MIL telling me that she puts her lettuce seeds in the fridge before planting them, or "they won't grow".
I can't think of any garden-veggie seeds that we "stratify" (refrigerate or freeze) before planting. Stratification is recommended, or deemed necessary, for the germination of certain flower and tree seeds. I believe that our vegetable seeds, handed down through ancestors in various parts of the world, generally had a very lengthy history of being fairly easy to grow — and stratification wouldn't have been easy or possible to do centuries ago.
Possibly, though, there are certain varieties of lettuce that do germinate more readily if refrigerated first. If so, I just don't know of them.
Nature generally uses the principle of produce a lot of seeds, let the winds, rain, birds, and other forces of nature act upon them. BUT, then things don't grow in rows or convenient beds and may get established very spottily here, heavily there. Horticulture and agriculture involve more human control and have enabled people to have more of what they want,
when they want it, and with greater ease of finding & harvesting.
I've known people who've experimented with broadcasting a mix of seeds, or letting the plants re-seed themselves in a given area. Can't remember any of this working out too satisfactorily. The experiments were all abandoned within a year or a few.
I got thinking about that this morning and want to know, just out of curiosity, what do you all consider the best way to handle and treat seeds for sowing, before and when the time comes? Do you aim for an "ideal" depth or scatter them and hope for the best, or do what I do and just stick them deep enough in the ground to ensure they are covered well enough, but not too deep so they won't find their way up?
In my experience, ideal seed depth is a more-or-less sort of thing, with beans (for instance) being planted deeper than carrot or lettuce seed. You develop a feel or knack for that, but beforehand can consult seed packet blurbs or online gardening sites. With small seeds like carrots, lettuce, radishes planting just a little under the top layer of soil keeps them damp, and prevents irrigation water or birds from disturbing or removing them before they take root.
