William Bronson wrote: I garden in a city lot, tires are not as bad as what's already there.
The Environmental Protection Agency acknowledges that more studies of crumb rubber need to be done, and has retracted an earlier assurance that crumb rubber turf is safe. Both the EPA and the Consumer Product Safety Commission, however, recommend and promote rubber mulch. The EPA has worked with industry representatives and state officials to increase the use of tire mulch in playgrounds, and the CPSC recommends mulch in the “Bible” it provides to playground planners across the country.
According to the EPA, benzene, mercury, styrene-butadiene, polycyclic aromatic hydrocarbons, and arsenic, among several other chemicals, heavy metals and carcinogens, have been found in tires. Studies have found that crumb rubber can emit gases that can be inhaled. When the material gets hot, it can increase the chances that volatile organic compounds, or VOCs, and chemicals can “off-gas,” or leach into the air.
Dr. Landrigan, whose research in the 1970s on children exposed to lead by a smelting company, is credited with spurring the widespread regulation of the heavy metal, said that currently available studies on rubber infill are “inadequate.”
There is not one study, he said, that attempts to measure the effects that long-term, repeated exposure to tire shreds or ground rubber could have on young children.
While the International Agency for Research on Cancer says that, at low levels of exposure, carcinogenic chemicals are safe, Landrigan said the repeated exposure of children to such carcinogens and chemicals put them at greater risk than adults, even at low levels.
“My concern as a pediatrician when somebody says that the levels are low is to ask the counter-question, 'What's low for a child?' ” Landrigan said. “I think for little children who play right down with their faces on the ground, who pick up stuff and put it in their mouths, who get crumb rubber on their skin in ways that adults would almost never get it on their skin, that any level of exposure to a known human carcinogen is too much.”
Behavioral traits unique to children, like putting things in their mouths, increase their risk of exposure. They breathe, eat and drink more relative to their body weight than adults. They also have many more years of life in which to develop disease triggered by early exposure to a carcinogen.
“Children’s cells and organs are rapidly growing and developing,” Landrigan said. “Developmental processes are very complex. They’re easily disrupted.”
Several substances found in tires are concerning, Landrigan added. “Butadiene is a known human carcinogen,” he said. “Styrene is a neuro-toxic chemical. It can cause injury to the brain and nerves. Truck tires also contain other toxic chemicals. All of these chemicals that are part and parcel of the tires get into the crumb, which goes into the field.”
Industry representatives and manufacturers say that crumb rubber is safe for children to play on because the manufacturing process binds the various components of tire, including carbon black and solvents, into a “matrix” that makes it impossible for them to leach out.
“Most people look at the raw materials going into tires and say, ‘This is a suspected causer of cancer, this could be an endocrine disrupter," said Blumenthal, the consultant. But after the manufacturing process, he said, “None of the raw materials that go into a tire are available.”
As long as rubber infill remains unregulated and unstudied by government agencies, she said, “We have to be independent thinkers. … If they’re not going to do it, then we have to put the dots together ourselves.”
“Used tires already exist, and in their solid state, they are as safe or safer than any other construction material. The process and the result of this global discard nightmare being recycled by industry, whether grinding them up for road base, burning them as fuel, or recouping the oil, releases more hydrocarbons while costing the global economy billions of dollars for tire cleanup and commercial recycling. Modifying tires to create green space and home gardening available to everyone would not only absorb hydrocarbons, it could well be the key to salvation for practically every family on the planet that is otherwise excluded from adequate sustenance. Personal tire recycling potential benefits far outweigh all perceived hazards.“
Bobo Trampin wrote:Just two ideas without experience on the subject for those, who think they are perfectly safe unless burned and decide to use them accodringly.
1.- stacking them up for potatoes, add a new tire and fill it with soil as the plants are rising above the last one. - I imagine it as an easy and plenty harvest that people have tried (tired?) already.
2.- It might save you the trouble of digging up a burdock root if you plant it on stacked tires of about a meter height.
As far as I can tell, the potato tower began with the idea of growing potatoes in tires. Somebody realized that you could achieve the necessary hilling quite easily by putting a potato on the ground and then filling up the tire with soil. That works very nicely. I’m sure it didn’t take long before someone decided to add a second tire, then a third, and the tower was born.
Articles about potato towers fall into four categories: those that promote the idea and never report on results, those that later report pretty normal potato yield, those that later report failure, and those that promote the idea and then unconvincingly report success (usually in support of selling a tower kit). An hour of research on the Internet provided a ratio of these types of articles of 74 : 11 : 9 : 2.
There are two insurmountable problems with the potato tower concept:
Tuber production is limited by foliage area.
Almost no potatoes produce additional stolons past the first few nodes above the seed piece.
We could kill this idea entirely, based only on the relationship between foliage area and the total energy budget of the plant. The main function of a plant’s foliage is to collect energy. That energy is converted to sugars and moved into the body of the plant for storage. This is where tubers come from. They are little balls of captured energy and water. Evolution does not allow for slackers. Plants have evolved to fully use the capacity of their leaves to capture and store energy. There is no excess energy for the plant to use to form more tubers, no matter how many stolons that you might convince it to produce. If you somehow forced the plant to produce ten levels of stolons, then you would get 10 times as many tubers that would be 1/10th as large (actually less, because so much energy would have to be expended on the formation and maintenance of all those stolons). If you want more yield, you need more foliage. Nobody claims that towers produce more foliage though.
The other problem is that potatoes simply don’t produce an endless number of stolons. Stolons are formed from the first few nodes above the seed piece and rarely any higher. Hilling up in excess of six inches is a waste of time and effort and only makes the plant work harder. The reason for hilling is not to make the plants form more tubers but to ensure that the tubers are covered by soil. Tubers need to be covered to protect them from pests, diseases, and sunlight, which will turn them green and increase the content of toxic glycoalkaloids. Plants will often survive extreme hilling, but you aren’t doing them any favors; they have to pump photosynthate and water farther, which costs the plant energy. The greater depth of soil can also be a barrier to water reaching the roots.
Nicole Alderman wrote:On the subject of potato towers, according to this article by a plant breeder (they specialize in rare South American tubers, so I trust their word), potato towers don't actually work and can actually be detimental. Here's the article https://www.cultivariable.com/potato-towers/
And some quotes:
I hilled up my potatoes a good three feet last year, filling in with mulch, duck bedding, wood chips, etc. I got quite a few potatoes...and they were ALL below all that mulching. The mulching did a great job of suppressing weeds, but there were no potatoes growing more than probably 6 inches above where I planted the seed potato. So, stacking tires will probably increase toxins in your garden, and is likely unnessesary for growing potaotes. And, if you want to turn grass into a garden bed, growing potatoes is a great way to do that. I made my potato bed last year on top of grass and buttercup, surrounded by grass and buttercup. There is NO grass or buttercup in the bed this year. I call that a major success!