A belated Amen to the Roberts' wise words on organic matter in the soil.
Building the organic content of your soil is the best thing you can do for
your garden. Your pest problems will diminish and you will find you need
less (actually no) fertilizers from a bag. The soil microbes that thrive
on organic matter will provide abundant nutrition for your plants for free!
And, as the Robertses pointed out, predatory mites and nematodes will
deal with many soil-borne pests.
A neat example of a nematode predator is the lasso fungus, which produces
millions of tiny loops on its mycelium (the mass of threads making up the
fungal body). When a nematode accidentially sticks its head in one of
these loops, the cells of the loop quickly swell and trap the nematode,
which then is digested by the fungus. The fungus thrives in soil high in
Every year I ask our town to bring me a load of the leaves they have
vacuumed up on the streets. Within ten months, this stuff has lost
two-thirds of its volume and has broken down into chunky leafmould (I like
the English spelling here; "leafmold" sounds suspiciously like something
spoiled!), ideal for mulching and for mixing into the soil. Most of my
perennial beds get about two inches of it every spring (if you put it down
in the fall, you're invinting voles to take up residence). It does wonders
and contains no seeds as is sometimes the case with compost. Surprisingly,
by the time it is black and unrecognizable it is neutral in pH despite
having begun as mostly oak leaves and pine needles.
Many communities dump their leaves in a common repository where they
compost, and you might be allowed to go there and fill up the pickup. Here
in Farmville, you can get a load of leafmould from any municipal employee
with a truck, who will be glad to do the shovel work for a very low fee!
But I suspect some towns would do it for you with a front-end loader
without charge, just to get rid of the stuff.
If you have lots of your own leaves, rake them up and run over them several
times with the lawn mower to shred them to speed composting. I used to
heap them up and scatter a couple of handsful of lawn fertilizer on each
10-12" layer before wetting them down with a hose. Did my heart good just
see the steam rising from that pile on a winter morning!
However, go easy on the mulch with TBs and other bearded types. Here at
least, they don't appreciate it, which is one reason why I don't use them
much in mixed borders. On the other hand, beardless types thrive with
mulches and it seems to me that JIs require less frequent transplanting
when they are heavily mulched with leafmould each year. Another caution:
with the exception of English irises, most bulbous irises do not much like
a soil full of organic matter.
End of sermon!
Best wishes, Bill
William A. Shear
Department of Biology
Hampden-Sydney VA 23943 USA
phone (804) 223-6172
FAX (804) 223-6374