permaculture

[Marimike6@cs.com]

<< Has anyone "cleansed" soil of Verticillum fungi? (I am unsure how to 
search
archives for this information). >>

Here's a technique I found just by googling "verticillum soil". You can also 
spell it "verticillium:

Soil Solarization
Using plastic to solarize the soil is an issue debated by many.
Does it destroy the soil structure? Can it be beneficial? It can be very 
useful in weed control and for clearing an area of vegetation without the use 
of 
herbicides. The beneficial soil organisms can take more heat versus the 
harmful 
soil pathogens allowing them to make a speedy return after solarizing an 
area. The way it works is the plastic concentrates the sun's energy which 
into 
turn heats the soil to a very high degree, sterilizing it. Thus killing off 
soil 
dwelling pests, disease and weed seeds.

 Depending on your climate solarization has been shown to control Fusarium 
and Verticillum wilts, crown gall diseases, possibly nematodes, grassy weeds 
and 
weed seeds. As for the nematodes; they have the ability to survive higher 
soil temperatures. The deeper the heat penetrates the soil the better the 
results. With optimum conditions disease and weed control can last up to 
three years.

 Soil Solarization Technique:
Soil solarization is best done during the heat of the summer. To begin you 
want to till the soil to a depth of at least 8 inches. Rake out all debris, 
smooth the area so it is as level as you can get it. Proceed to soak the soil 
to a 
depth of 18 inches. Make a slight depression at the boundary of the bed. 
Stretch some clear 4 mil plastic over the bed as tightly as you can, adhering 
it 
to the soil. Then use rocks, more soil, landscape pins, whatever you have to 
secure it snuggly in place. 
Next step is easy; let the area cook for at least 4 weeks. In cooler zones 
allow a period of 6 to 8 weeks for best results. Remove the plastic. Till the 
soil lightly, you are ready to plant.

 In more northern climates the addition of manures prior to putting down the 
plastic can help to speed the process via increasing the soil temps as the 
manure decomposes. This will increase the level of gaseous ammonia in the 
soil 
giving the solarizing process an extra kick. Maybe enough to control 
nematodes!
Another trick is to use two layers of plastic to create more of an insulating 
effect. This will trap more heat.
You can also incorporate shredded vegetables from the cruciferous family 
(broccoli stems, cabbage trimmings etc.) These vegetables have a known effect 
in 
ridding the soil of Verticillum and Fusarium blights. Let the trimmings dry 
out 
in the sun until brittle. Mix them into the top 6 inches of soil, proceed 
with the process.

 http://www.ghorganics.com/page25.html