[NAFEX] solarizing soil

david.maxwell at dal.ca david.maxwell at dal.ca
Sun Oct 18 14:16:49 EDT 2009

There is an interesting wrinkle to this.  It is quite possible to grow very fine sweet potatoes in 
Northern climes, (I am in Canadian Zone 5) by using clear plastic in the early spring to warm 
the soil, and planting the sweet potato slips through slits made in the plastic as soon as the 
soil reaches 60 degrees.  I did this this past year in a bed which had a fair amount of what we 
call twitch grass.  Not only did the plastic solarise the twitch grass out of existence, but the 
sweet potatoes thrived, making tubers under the plastic while the green tops spread above. 
(If any members want further information on growing sweet potatoes in the North, contact me 
off line.  This really is outside the mandate of Fruit Explorers (unless one is prepared to 
stretch the definition of a fruit unreasonably))

> You need to do this in a summer month.  Water the soil well, and cover
> with clear plastic, about 3 mil.  Weigh or fasten down the edges. Wait
> a full month.  The hardware clear plastic I've used will degrade and
> not stand a second use.  Even if it looks good, I would expect it to
> fall apart before it does the job.
> It used to be thought that black plastic would do better, as it heats
> up. The problem was that the plastic retained the heat, and heat
> penetrated the soil less deeply than with clear plastic.  
> ~ Stephen

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