seedling reemergence after first dormancy

M. Gastil-Buhl
Sun, 29 Dec 2013 12:47:21 PST
Nhu mentioned
"I had a high rate of germination with fresh seeds, but of course,  
none of the seedlings came back."
referring to Hesperocallis. I wonder why he says "of course". I have  
not attempted Hesperocallis. Am I wrong to expect most of my seedlings  
return after their first dormancy?

I would read with keen interest the experience of others with their  
seedlings successful reemergence. I have mixed success. I can make a  
few generalizations from the small sample of species and growing  
conditions I have tried, all winter-growing, summer-dormant and mostly  
iridaceae. The most clear trend is that seeds sown directly into deep,  
raised bulb boxes fully exposed to sun, rain, and frost have fared  
best both in the first and second season and have resulted in high  
yields of bulbs per number of seeds sown. Those include Babiana spp.,  
Pasethea carulea, Moraea polystachya, Dichelostemma capitatum and  
Freesia laxa, none of which are difficult to grow. The exception to  
that rule is the Tropaeolum hookerianum which self sowed a dozen  
vigorous sprouts last year, none of which returned. My experience with  
potted seedlings is the opposite. Some of the tiny seed pots are  
growing well in their second season but more than half have yet to re- 

I have some ideas what factors may most strongly affect the ability of  
seedlings to live through their first dormancy. The first I have read  
from the PBS list and elsewhere, that the juvenile corm or bulb must  
achieve a minimum size, storing sufficient energy to support emergent  
growth. I started my seeds months later than ideal in 2012 so the  
seedlings did not have a long enough winter to grow before going  
dormant.  However, the in-ground sowing was also done late. My second  
idea is that in-ground growth experiences much damped oscillation of  
day and night soil temperature compared to the tiny seed pots. That  
heat may inhibit corm growth, which may require cooler temperatures as  
it does with Crocus. Also I suspect but have not shown that moisture  
varies more in the tiny pots than in-ground.

What methods do PBS members recommend to increase the chances of  
seedlings surviving past their first dormancy? And if a seedling pot  
does not re-emerge, should it be retained for another year as with yet- 
to-germinate pots?

- Gastil
Santa Barbara, CA, cool and dry Mediterranean climate
All seedlings grown outdoors

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