Re: Mulch vs reseed?
- Subject: Re: Mulch vs reseed?
- From: T* &* M* R*
- Date: Tue, 24 Apr 2001 09:27:16 +1200
susannah wrote:
>
> Hello Moira --
>
> I meant to say it in my previous post, and then I forgot to, but I actually
> thought you WERE suggesting compost, and that I was just elaborating on
> your good idea. Nan seemed to be assuming that whatever she would use for
> mulch would be something that wouldn't allow the flower seeds to sprout, so
> when you proposed in your previous post that she "...mulch just when your
> plants are going over but before they actually drop their seeds", I
> figured you meant that she would be mulching with something at least
> mostly-composted. ...Now I'm just confusing myself, trying to figure out
> what everyone else meant by what they said, so I can write this
> clarification of what I said!
>
> I think you're right about the drying-out been potentially a problem, and
> about dry compost being better than nothing. I'm trying to remember how
> dry the compost gets in my beds, under the plants' leaves, but I really
> don't recall. I assume that the hybrid and California poppies are
> evergreen where Nan is, so she could compost around them in the fall or
> winter, whenever rains start in San Diego, and the sweet peas could come up
> through the compost. Or heck, if she does have a lot of mulch of some sort
> that seeds won't sprout in, at that time of year she could go ahead and use
> it, because, by the time the new seedlings sprout almost a year later, it
> should be quite well composted. Would that work? It has the added
> advantage that Nan doesn't have to do anything now, in the spring, when
> there's never time to get all the garden chores done!
>
Hi Susannah
To Me compost and mulch are two different materials.
Compost (worth its weight in gold, well, almost) is the finished product
one gets from the organic matter in a compost heap after all the
organisms have digested and redigested it down to a fine blackish
earth-like material which is almost pure humus, and teeming with useful
organisms to enliven the soil to which it is applied.
Nature rarely makes compost herself. The closest would be the result of
the breakdown of a fallen tree or other biggish pieces of wood (like for
instance the stuff inside a very old large stump I saw on a bush walk
yesterday which had a sizeable new tree growing in it as though in a
large pot!) The main reason _we_ use it is to speed things up for the
concentrated and high-pressure growing we like to do both with
ornamentals and food crops.
Mulch to me is any unprocessed or only partly processed materials appled
to the surface. It can even be something almost inert like pebbles,
gravel or crushed shell (whose breakdown would be virtually
imperceptible) or any sort of organic matter, unrotted or only partly
rotted (even half-made compost), and left there to be processed by the
organisms already present in the area. It can be very short-term like
grass clippings, or long-term like mature woodchips or bark or any
combination in between. One of the most valuable mulches for improving
soil fertility and texture has been shown to be ramiel wood (the wood of
young twigs and branches up to about 3" diameter). So chipped prunings,
hedge trimmings and similar green wood are one of the most valuable of
mulches nutritionally.
There are two main differences between applying mulches and finished
compost. First the depth, to be effective most mulches should be applied
in quite a deep layer, at least 3", while 1" of the more concentrated
compost is plenty plenty (any more at one time and you are putting on
too much for the organisms to use, which is wasteful for you and bad for
the groundwater which has to absorb the surplus)
The other point is that while mulch will virtually provide its own
sunshield, with the decay happening from the bottom up, compost has its
inhabitants evenly distributed throughout and in the thin layer normally
applied there is little protection for them from dessication. To
counteract this the wise gardener always puts a protective mulch over
the compost layer.
You will observe I am talking only of putting the compost on the
surface. Modern research and the experience of numerous home gardeners
has shown this is always preferable to digging it in which, however
carefully done, disrupts the soil structure and organization. This
apparently applies more especially to difficult soils, particularly
clay, but also I have been learning recently to many sands also. I have
to take this on trust as my own soil is a stony loam with few problems
(lucky me).
And an answer to Tim Dutton and his observations (Hi Tim how are things
with you? long time no hear). The main difference between your two
mulches is undoubtedly their opacity. A mulch open enough to let any
light through will kill existing weeds, but not suppress new weed
germination, This has been shown for instance in a comparison between
the weed suppressing effects of shredded bark and bark "pebbles" (only
the former stopped new seedlings coming through). I have found it very
helpful to underlay weed-suppressing mulches of any kind with
overlapping newspapers, put on really thick, say around 5-10mm (1/4-1/2"
for you Americans). By the time the buried paper breaks down the mulch
will usually have settled and packed down enough to exclude light.
Unlike any plastic layer, the paper seems to have no adverse effects on
plants growing in the bed, in fact it may help to retain moisture and
certainly is beloved by worms. In fact it has proved so good for this
that I even plant vegetables such as cabbage or squash in a bed with a
mulch underlay of paper, but in this case no more than three sheets. (no
doubt one could do this in parennial borders too).
Moira
--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata (near Wellington, capital city of New Zealand)
