fertilizing bulbs

Rodger Whitlock totototo@pacificcoast.net
Fri, 08 Apr 2005 09:35:43 PDT
On  7 Apr 05 at 8:39, Judy Glattstein wrote:

> And what about bulbs that do not synchronize flower and leaf production?
> The majority of colchicum for example - flowering  must draw on stored
> food reserves. These reserves then, are not replenished until leaves grow
> the following spring. And the clever colchicums also wait until spring to
> produce their seeds, when food reserves are re-supplied.

On  7 Apr 05 at 7:57, Merrill Jensen wrote:

> I've always followed the "Observe, Deduce, Apply" method of fertilization
> in these cases.  No foliage, no fertilizer.  I have applied any good
> organic fertilizer just when the new leaves start to nose out of the
> ground.  This has worked well in the past and I'll do this with my new
> South African friend, Amaryllis belladonna...

I'm not so sure the "no foliage, no fertilizer" rule is sound. A few years 
ago, I decided that my entire garden needed fertilization: the soil is a 
pretty good heavy loam, but in the forty years since the house was built, 
there's been a constant crop of vegetation taken off it, and I felt that 
the basic nutrients were very likely depleted.

More by accident than design, I ended up broadcasting fertilizer on the 
entire garden in early September so it could be washed into the soil by 
the rains that started a few weeks later. [I used 13-16-10 at a rate of 
about 2 oz per square yard.]

Everything was fertilized: lawn and flower beds both, willy nilly.

The next spring, to my surprise, many spring bulbs flowered more strongly
than in the past, including e.g. Narcissus 'Peeping Tom'. [Peeping Tom is
right by my front steps and gets more attention than many others.]

I had always understood that in narcissus, the flower primordia are formed 
the previous summer and hence inferred that fall fertilization would have 
no effect on flowering the next spring. 

I suspect the "no foliage no fertilizer" rule is flawed because bulbs can 
and do push roots out into the soil very early, and these roots *must* be 
absorbing nutrients. Photosynthesis comes later when the foliage emerges.

Fall fertilization isn't necessarily a panacea, but it has had 
surprisingly good results for me. There's a sense that since most plants 
are actively growing in the early fall, they absorb nutrients then to 
boost their performance when warm weather returns in the spring.

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

on beautiful Vancouver Island

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