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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