Insider's List of Gardening Tips
Silver Reflective Mulch
By Leslie Doyle
In this test: The soil has been treated with MICROBES, fed Arizona's Best Tomato & Veggie Food and covered with silver reflective mulch for a Triple Whammy. Now, I only have to deal with the birds and neighbor's dogs & cats (and wind, and virus and . .)
I was very impressed with the results of the red reflective mulch I trialed last year on Hawaiian tomatoes. Normally producing a 10 oz tomato, Hawaiians were increased to over a pound and I picked 160+ pounds off 2 plants, WOW. Curious as to the how and why, I got on the phone and called all over the place. I talked to Ag guys, growers, farmers, and the manufacturers and distributors of these 'wonder' mulches.
"If you think the RED MULCH is great, wait until to try the SILVER, it's even BETTER," he said. I was talking to an Ag guy up in the hot San Joachin Valley. He was not the only one who gave a similar response. Some research I've done has turned up these excerpts from industry publications, papers and reports on the testing of silver, white and red reflective mulch.
Summers, Charles, UC Davis entomologist, said this in an article by Marni Katz in a special to Ag Alert. "I think the take-home message is that plants grow much better and more rapidly over reflective mulch than one on fallow beds and cover crops, we see a bigger plant, more flowers and consequently, more fruit."
Summers attributed the surprising difference to the increased photosynthesis and more even temperatures afforded by beds grown under reflective mulches. Because the mulch reflects sunlight up into the undersides to the canopy there is higher photosynthesis, leading to a more rapid start for the plant and more rapid growth. In addition, the mulches hold temperature at a consistent level by absorbing and then holding heat, which could lead to more growth during the evening and nighttime hours. He also stated, "The reflective mulches work against pests by essentially confusing the pest's interpretation of what he sees."
Unscientific words from the Tomato Lady: "The way I understand it best is by equating our light in Las Vegas to the amount of light the plants get in Alaska. The veggies are huge up there, , , they have 20 hour days. The further South you go the days get shorter. I remember Detroit as a teenager and having to be home by dark, that was about 10 p.m. in the summer. I take the position that you should never shade your veggie plants.
HOWEVER, it is a good idea to shade only the fruit if there are not a lot of leaves doing this job. I use 2-foot squares of green shade cloth, fold it in half and cover only the tomatoes, not the leaves, to protect them from sunscalding. (I plant peppers 3 to a hole to give more shade to the fruit.) I also use twist ties to fasten the cloth to the tomato plant so it doesn't blow away. THE LEAVES DON'T WANT ANY SHADE, they want more light than nature has provided Las Vegas, hard to believe, isn't it? I feel like one or the other of Siskal and Ebert when it comes to the long established gardeners in town. I am directly opposed to shading veggie plants & particularly tomato plants.
Plus: "This year I will hang the silver mulch down my south facing
concrete block wall. Normally this wall bakes in the sun and releases
its heat at night. This heat coming from the wall at night can prevent
tomatoes from setting fruit. However, my theory is that if I drape the
wall with the silver reflective mulch, the light will bounce out into
the top of the tomato plant and keep the wall cooler. This extra light
on the plant should give me almost a 100 pounds of huge Hawaiians. Don't
laugh, I think this is probable. Yes, my yard will look like a house of
mirrors, but I am on a 'mission'. Bill on the other hand . . well, let
me say he is the most tolerant man in the world and thinks I am very smart
(for this I love him immensely.)
Harry Andris , R. Scott Johnson, Carlos H. Crisosto. UC Cooperative Extension, Fresno County, Fresno County Dept. of Pomology U of C, Kearney Ag Center Dept. of Pomology, U of C, Kearney Ag Ctr. Writing about Nectarines and stone fruit; Excerpt: "With the improvement to the metalized-reflective film surface, which made the film brighter and by making it wider (for the orchard), . . . . growers . . . now had a product available which could dramatically improve fruit color under our hot San Joaquin Valley conditions." Also, "These studies demonstrated that both the red and the white films could improve fruit color but not to the extent that the metalized films did."
Summers, Charles G., and Stapleton, James J. Kearney, Ag Center, U of C, Parlier, Ca. Excerpt: "We found that metalized and silver embossed plastic mulches were effective in both reducing and delaying colonization and buildup of whiteflies and aphids, and reducing and delaying the incidence of aphid-borne viruses."
Another excerpt; "grower fields of cucumber, pumpkin and zucchini squash . . . In cantaloupe and cucumbers, reflective mulches reduced alighting by alate aphids and delayed the incidence of aphid-borne viruses by 6 weeks. Aphid and whitefly numbers and the incidence of virus infected plants were lower and yields higher in plants grown over reflective mulches."
Another: Yields from mulched plots were 200 to 300% higher than those from unmulched plots. In grower trials, aphid and whitefly numbers and the incidence of squash silverleaf were significantly lower and yields significantly higher in cucumber, pumpkin, and squash grown over metalized reflective mulches. In sweet corn, metalized mulched repelled the corn stunt leafhopper, , , resulting in a significant reduction in the incidence of corn stunt disease, , , and produced significantly higher yields.
Leslie Doyle, April 2002
© Sweet Tomato Test Garden 2003 - All Rights Reserved