Cannot for the life of me find the answer online. I live in central inland FL, for reference.
What I can rule out:
The seeds are not too shallow: corn and beans get buried 3-4 inches, tomatoes and peppers 1-2 inches, etc.
It’s not birds or squirrels: I’m in the garden constantly, no critters around, and there are never any dig or scratch marks, just smooth sand.
It’s not the root pushing up the seed: They are, without fail, not germinated.
It’s not the soil being washed away: the beds are the same level they’ve always been.
What I think it could be:
Sandy soil is compact and dry, despite twice daily watering, so maybe the cycle of the seed expanding/contracting causes it to climb up the soil?
…Perhaps the ants are pulling them up somehow? I find this unlikely, since there are never any tunnels near the seeds, but many of the corn kernels do get bug eaten by the time I find them on the ground (as dry as in a packet), so I can’t rule it out
It’s not the biggest deal in the world, since I compensate by burying the seed deeper, but I think that adds a selection criterion of the seed being able to push up that far, where I’ve already got so much selection pressure going on. Also, I’m just plain curious. Any answer Google can’t come up with has got to be interesting.
This happens to me too, and I have a clay soil. It particularly happens with peas and beans, larger seeds. I don’t notice it with smaller ones. And it doesn’t always happen.
My theory is your first suggestion; that the seeds expand and contract due to being wetted, and work themselves out. Or that they sort of “float” up through the moistened soil.
Also, sometimes I think at least some soil is washing away from mine, even with careful watering, so they aren’t working up as far as they seem to be.
Y’know, now that you mention it, I remember that I did dig up this area last year and mix all the layers together, the bottom of which was beautifully orange clay. I also thought it was only the big seeds, corn and peas for me, but yesterday as I was reseeding pepper seeds, I found some older ones on the surface just the same. Maybe it happens will all the seeds and only the bigger ones are noticeable before the environment does away with them.
Very interesting! So maybe it’s the frequent walking around the beds, causing vibrations, that are bringing the seeds to the surface. Lol guess I’ve been sabotaging my own self.
Could be a mix of the two theories, like both of these forces acting on the seeds simultaneously.
I’m going to guess it’s related to density, lower density particles rising to the top. Hmm… actually maybe also particle size, or mainly that! As pointed out above.
We see that here in heavy clay as well. Heaving frequently throws established bulbs out of the ground. This year I came to understand the mechanism a little more and started joking to myself that we don’t need to till because nature tills for us
Ha ha ha ha! You know what, that’s a really interesting point I hadn’t considered. Winter freezes and thaws often do disturb the soil. That must be one of the mechanisms by which annuals (in temperate climates) get empty soil to germinate in. I had been thinking that it was mainly animals digging that disturbed the soil to make habitat for annuals. But the weather could play a part all by itself, too! Cool!
This is very interesting! I kept having cloves of garlic do this and really wondered why I kept finding them on the surface despite sticking them back in every time I find one. Our ground is currently defrosting.
For me fava beans only do this. Last spring much much worse though, coincided with much more frost. This year not much and i dug em in deeper. Sprouting rate just as shitty so far
I place seeds into the ground, then I compact the soil. A lot!
Compacted soil keeps the seeds in place better. It makes it harder for animals to carry off the seeds. It enhances germination by getting more soil moisture into contact with the seed.
For years, people told me that animals eat their seeds, or pull plants. I couldn’t understand, cause i have the same animal species and never had a problem. When i questioned why, it seems to happen to people that like soft fluffy soil. That’s not me. My grandparents taught me to compact soil tightly around seeds, just like their grandparents taught them. It’s so engrained in my brain and culture that i couldn’t imagine that someone would intentionally fluff up their seed beds.
Huh! I wonder if that has something to do with soil type! Do you have sandy soil, like I do? It’s possible clay soil needs fluffing up, and sandy soil benefits from being stomped down.
