[Market-farming] New to the list; Black Plastic Mulch Overheating

Bill Shoemaker wshoemak at inil.com
Thu May 8 08:12:14 EDT 2008


Black plastic mulch is used in the southern US quite successfully. The huge 
conventional tomato crops in Florida are often grown on it. The plants will 
shade the plastic once they gain enough size. Before that, the heat from the 
plastic will promote growth, the plastic conserves moisture and the weeds 
are totally controlled. Put drip irrigation tape underneath and you can 
really manage the crop. In the future I think bio-degradable mulches will 
become more common and affordable. Growers will be able to till in the 
plastic and let the microbes eat it, a considerable labor savings and 
environmental improvement.

We have been evaluating 10 plastic mulches of different colors with 
tomatoes, peppers and melons for several years. There are real differences 
in plant performance. Which color works best depends on which plant you're 
growing and when you plant. In the end, because of price differences in the 
products and black being cheapest, black is the best all-in-one mulch for 
warm season crops generally in our area. Because conditions, including 
daylengths, differ in other areas, results might be different in other 
areas.

Lucy's point about transplants wilting is good. I've lost plants when 
conditions are hot and sunny. Plant early in cool, cloudy conditions if 
possible. If you put a spadeful of soil around the base of the plant, 
sealing the hole in the mulch, it will stop the hot air from funneling out 
through the hole. The concentrated stream of hot air is what kills the 
plant. Sealing the hole prevents the damage. I knew a couple of vegetable 
growers who used clear plastic on tomatoes, cucumbers, peppers, squash and 
other summer crops. It gets even hotter than black plastic but weeds grow 
under it. They would seal the holes like I described above. It would get so 
hot that the weeds underneath would fry but the crops would thrive.  They 
practiced this for 30 years before they retired. They still do it in their 
garden. They also had earlier crops than growers with black plastic mulch.

Bill Shoemaker, Sr Research Specialist, Food Crops
University of Illinois - St Charles Horticulture Research Center, zone 5b
www.nres.uiuc.edu/faculty/directory/shoemaker_wh.html




> And, also, does anybody in zone 6b have experience using black plastic
> mulch with tomatoes?  I would like to try this but I'm concerned about
> overheating the soil.  If started early enough would the shade from
> grown plants be enough by mid summer to keep this from being a
> problem?



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