I mulch my tomatoes heavily and replenish the mulch throughout the season.
Blights are kept to a minimum where before they decimated my plants. My
plants survive our hot summers a lot easier now with far less water. I've
never had a problem with pillbugs. I haven't had any crown rot on my
perennials, but I don't mulch over them as it's not necessary with our mild
winters. I also don't mulch right up against my trees as it can cause diseases
to develop. I think it may really depend on your weather and perhaps even
things like ground moisture.
> > > >> My question is, why would anyone ever choose *not* to mulch??
> > Simple: some plants, e.g. ones that need good drainage and prefer rocky
> > "poor" soil can get crown/root rot diseases by having a high
> > concentration of organic material near their root system. The drainage
> > may become less in this case as well.
> > Slugs, pillbugs etc can also be encouraged by the presence of organic
> > mulch. So, the holy grail of "mulching is always a great idea" -
> > especially organic mulches - should be viewed with Caution. I think
> > this mulch mania can sometimes get overblown. Nothing works to improve
> > conditions in all cases; it just ain't that simple. Sure, it helps in
> > most cases, but be careful, don't run with scissors.
> > John R> z8b Austin
> An interesting post! I, too, am beginning to reconsider the "mulch is
> always a good idea" advice I've been handing out.
> The question I have concerning your post is that you didn't specify which
> particular pathogen you were referring to. When you say that mulches can
> cause "crown/root rot diseases" are you saying that mulches encourage
> Phytophthora, which thrives in wet and hot soils? Pythium?
> I'm beginning to suspect that mulches do indeed supress Phytophthora, but
> in so doing, end up encouraging Verticillium or perhaps Fusarium Wilts
> through the following mechanism: Mulches allow the soil to remain cool and
> moist, so even in the height of summer, Springlike conditions are
> perpetuated. As I understand it, these conditions are ideal for the Wilt
> diseases to take hold. Normally they attack during the cool soils of
> Spring, but lose influence as the soils get hotter. With mulches they can
> increase in virulence longer than normal and cause enough damage so that
> when hot weather rolls around, the plants lack enough water transport
> mechanisms to sustain them during the heightened water transport demands
> of hot weather, and collapse, even though the initial attack actually
> occurred months earlier.
> What do you and others think?
> David Deutsch
> Gondwana Gardens