Roots Out the Drainage Holes
Thu, 26 Oct 2006 13:55:41 PDT
On 25 Oct 06, at 10:04, Jane McGary wrote:

> I don't think this is necessarily true, especially with bulbs. Many
> bulbs form annual "contractile" roots that, as they mature, contract
> to pull the bulb deeper into the soil.

And they keep pulling until the bulb reaches a level with the "right" 
temperature. It's a protective mechanism to get the bulbs down deep 
and away from the soil surface where they are more at risk of being 
eaten, washed away, or otherwise harmed.

For much the same reason, some bulbs, Iris danfordiae among them, 
split into gazillions of small rice-grain bulbs if planted too 
shallowly. The bulb is responding to thermal indications that it's 
near the surface, so splitting will work well as a propagative 
strategy. Plant them way deep, they get the message that splitting is 
not a good strategy, and turn their energies to flowering and setting 

I. danfordiae needs to be about a foot deep for reliable repeat 

Tulips are notorious for forming "droppers". Somewhere I read a brief 
article by Lady Skelmersdale in which she commented on the difficulty 
her nursery had in filling orders for Tulipa sprengeri: they had a 
bed full of it, but the bulbs were deep and hard to find.

> danger of growing bulbs in pots is that, if not lifted often
> enough, they will be pulled down into the drain hole and plug it
> up, resulting in no drainage, rot, or having to break the pot to
> free the bulb. This last is an argument for using plastic mesh pots
> instead of solid pots in a plunge situation -- though I still rely
> mostly on terracotta. 

You should never be afraid to break a terra cotta pot. Yes, I know, 
the big ones aren't cheap (and, frankly, these days neither are 
little ones of good quality), but they really have to be viewed as 

And the therapeutic value of taking a hammer to a big pot and 
smashing it to smithereens is not negligible. Better than taking out 
one's frustrations on one's fellow man.


Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate

on beautiful Vancouver Island

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