That would be solarizing and it is done with CLEAR plastic rather than black (black shades, clear heats) and it is done when the sun is highest in the sky as basically, you are using the greenhouse effect to superheat the soil. In Arizona, Pamela, it might still work even though we are past the longest days of the year. It can’t hurt. To enhance the effect, add a second layer of clear plastic with a two inch air gap in between. Cut the foliage back to the surface first and saturate the soil so it holds the heat for as long as possible. Turn the irrigation off to the bed. It usually takes six to eight weeks and you may have to repeat it after the initial treatment. Here’s a link to more details on how to do it <https://waterwisegardener.com/2011/08/…>. Nan > On Oct 11, 2020, at 5:55 PM, Pamela Slate via pbs <pbs@lists.pacificbulbsociety.net> wrote: > > Hi Friends, > I have a 12' X 4' raised bed where I've grown a number of bulbs. > Unfortunately, two spp. of Oxalis has misbehaved to the point that I've had > to remove all plants I wish to keep, wash all roots to rid them of invaders > and relocate them. Once the bed is empty except for the lusty Oxalis, how > do I kill those remaining bulbs, some of which are two plus cms in diameter? > > Sometime this year, I recall a post that said if you cover the entire area > with dark plastic and of course, suspend watering, new bulbs will be unable > to form. But what about the old, mature bulbs? It seems they will continue > to be viable for a long, long time. > > SOS, please help and thanks very much, > Pamela Slate > AZ USA Zone 9-ish after the most brutal summer ever > _______________________________________________ > pbs mailing list > pbs@lists.pacificbulbsociety.net > http://lists.pacificbulbsociety.net/cgi-bin/… ***************************************** Nan Sterman, Waterwise Gardener Garden Journalist • Author • Speaker Gardening Coach • Garden Designer • Horticulture Consultant http://www.waterwisegardener.com/ <http://www.waterwisegardener.com/> 760 634-2902 PO Box 231034, Encinitas, CA 92023 Order my latest book, Hot Color, Dry Garden at http://www.waterwisegardener.com/writing/ <http://www.waterwisegardener.com/writing/> Sign up for my newsletter at http://www.waterwisegardener.com/ Host of A Growing Passion on KPBS TV and on-line at http://www.agrowingpassion.com/ <http://www.agrowingpassion.com/> _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/…