Dear Trudi,

Thank you very much for your inquiry. In my mind, the clear plastic is superior in the case of solarization because of heat buildup. You desire the plants to die quickly I assume and excessive heat is one great way. More heat will build up due to the sunshine through the clear plastic and the grass will die faster.

Again, thanks for the question and let me know if you have more.

Respectfully

Trey Rogers
The Yard Doctor

Hi Trey,

Thank you for your answer. I do have some other questions about solarization, I think it's an affordable, non-toxic way to make changes to your sod or soil.

I assume there are other benefits of soil solarization beyond killing existing plants.

Can there be small seeds killed?

Will solarization reduce or eliminate some soil-borne fungi/virus such as those which cause verticillium and fusarium wilt, et al.

And finally, to what depth could this happen--obviously the hotter the temps and the greater duration of covering will effect the pentration--could optimal solarization produce results to a six, maybe eight inch depth? This would make for a limitation of how deep you want to turn your soil after solarization without bringing up to the surface surviving fungi or weed seeds.

Thank you kindly,

Trudi

Trudi, if I may jump in here. Questions often come up regarding solarization. It's used too little for effective weeds and pathogen control, but the opportunities for failure are high.

Black plastic, as mentioned earlier, is not effective (at all) in solarization. The heat is absorbed by the plastic, which will then merely warm the upper surface of the soil. Sunlight must penetrate deeply into the area in order for solarization to occur. As a matter of fact, you want to use the thinnest grade of clear plastic that you can find.

Other factors for success include: ambient temperature, number of days with sunshine, type of soil, depth that soil was tilled, proper preparation of site, and the correct installation of plastic.

Yes, 'proper' solarization will kill many soil pathogens and weed seeds, but temperatures must reach at least 122o F for the most stubborn. Many are not that difficult to kill. Pathogenic bacteria, fungi, and virus are all susceptible, as long as they are soil borne. Also, if you turn under a crop of (say) diseased tomatoes, a thorough solarization process will kill those pathogens. Nematodes are steamed out readily.

Beneficial (and essential) microorganisms are killed in the process, too, but it appears that they are able to rebound rapidly, while the pathogens are not. Earthworms, of course, are able to move out of the area or go deeper for the duration.

In locations where solarization has proven essential to raising agricultural crops, the fields 'take turns' in being put out of production so that the 50 or so days of beneficial steaming can occur under that plastic.

I hope that I've answered your questions and also hope that I haven't been presumptuous in doing so.

Is garden solizaration harmful to earthworms?