Sowing at depth

[annew]

Just to emphasise Ian's plea to sow bulb seeds at depth, I just unpotted some 1 year old snowdrops to get some out for a friend. I sowed the seeds halfway down a 12cm deep pot. The young bulbs were all within 1cm of the bottom of the pot.

[iann]

Doesn't this mean you don't have to sow at depth because the bulbs will make their own way down?

[Maggi Young]

But the point is that by sowing them at depth you get more mature bulbs more quickly because they haven't had to expend energy taking themselves down.....

[gote]

During the years, we have probably been sowing many seeds far too shallow.
Deep sowing has several advantages among which are that they are less exposed to dryness and other vagaries such as damage from weeding.
However some seed need light to trigger themselves into germination.
This  means covering less than 10 mm perhaps less than 5 mm.
A list of species that can / should be sown deep would be very helpful. I think that this is a subject that is usually forgotten in the literature.
Göte

[cohan]

an interesting topic! like gote, i would be interested in knowing which species/genera this is especially suitable for, since i presume for many others this would be fatal..is this a rule of thumb for most bulbous species? only those from cold places? what about things such as cape bulbs that grow on/near the surface?
i'm not challenging, just hoping for more detail, being still quite a neophyte in the world of seeds, and the more so with 'outdoor' plants!

[Ian Y]

I have listed all the bulb seeds that I sow at depth in the bulb logs over the last 8 years and I have given reasons why.

My general rule is to work out how the seed is distributed in the wild. If it is distributed by mechanical action like a catapult flinging it out of the capsule there is a good chance that it should be surface sown - for example the Western American Erythroniums, Fritillaria.

Wind dispersed seed should also be surface sown - many Allium seed heads fall off complete and act like tumble weeds dropping seeds as they are blown over the ground.

Seeds that have elisomes,  sticky attachments to attract insects to collect them and take them underground should be sown at depth. These include Narcissus, Crocus, Cyclamen, etc.

Of course you will succeed with all seeds by surface sowing -just them covering them with a layer of gravel and if you sow them all at depth some will fail to germinate at all so you do need to know which is which.
The big advantage in sowing the relevent species at depth is that you get flowering sized bulbs at least one year quicker.

[cohan]

thanks, ian..

[gote]

Just a note.
There is a Japanese report on the net that covers germination of Cardiocrinum glehnii. It seems that it has a built in delay that makes it lie around an extra season. This delay can be overcome by suitable treatment.
My guess is that by waiting another year, the seed get another layer of leaves on top and thus germinate lower down than "normal" spring germinators.
Cheers
Göte