{"id":2967,"date":"2020-03-27T00:08:15","date_gmt":"2020-03-27T07:08:15","guid":{"rendered":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-594\/"},"modified":"2024-04-13T12:35:13","modified_gmt":"2024-04-13T19:35:13","slug":"growing-edible-plants-in-galvanized-containers","status":"publish","type":"pal","link":"https:\/\/depts.washington.edu\/hortlib\/pal\/growing-edible-plants-in-galvanized-containers\/","title":{"rendered":"Growing edible plants in galvanized containers"},"content":{"rendered":"

Is it safe to use galvanized containers (in this case a large<\/strong>
\ngalvanized tub like the kind used for watering livestock) in which to<\/strong>
\ngrow root vegetables, herbs, etc? I’ve seen some sites sell these for this<\/strong>
\nuse, but there are also some postings referring to the potential for ill<\/strong>
\neffects of anti-rust coatings.<\/strong><\/p>\n

 <\/p>\n

You may want to consider both what goes into the galvanizing process, and what could be leaching out of containers as the coating wears down over time.<\/p>\n

Here is information on the process of galvanizing from the American
\nGalvanizers Association.<\/a> Excerpt:<\/p>\n

“What are the steps in the galvanizing process?”<\/p>\n

    \n
  1. Pre-inspection – where the fabricated structural steel is viewed to
    \nensure it has, if necessary, the proper venting and draining holes,
    \nbracing, and overall design characteristics necessary to yield a quality
    \ngalvanized coating<\/li>\n
  2. Cleaning – steel is immersed in a caustic solution to remove organic
    \nmaterial such as grease and dirt, followed by dipping in an acid bath
    \n(hydrochloric or sulfuric) to remove mill scale and rust, and
    \nfinally lowered into a bath of flux that promotes zinc & steel reaction
    \nand retards further oxidation of the steel… (steel will not react with
    \nzinc unless it is perfectly clean).<\/li>\n
  3. Galvanizing – the clean steel is lowered into a kettle containing 850
    \nF molten zinc where the steel and zinc metallurgically react to form
    \nthree zinc-iron intermetallic layers and one pure zinc layer<\/li>\n<\/ol>\n

    Based on the above, one concern would be whether the zinc would be
    \nharmful. Zinc is one of many nutrients needed by plants, but I couldn’t
    \nhazard a guess as to what effect the zinc from the coated steel would
    \nhave, if any, or whether the galvanizing process involves other
    \nsubstances.<\/p>\n

    The book The Edible Container Garden<\/em><\/a> by Michael Guerra (Fireside, 2000)
    \nsays the following:<\/p>\n

    “Galvanized buckets are increasingly popular but don’t use them for
    \nericaceous or acid composts.” (This would be a compost which is
    \nlime-free. Usually soils in the Pacific Northwest tend to be acidic. I
    \ndon’t know from your message what part of the country you live in, but
    \nthis might be something to consider as well).<\/p>\n

    Another issue is that the metal containers will probably heat up quickly,
    \nmeaning that your plants might need more attentive watering.<\/p>\n

    Los Angeles County Cooperative Extension<\/a> offers the following information, in an
    \narticle on trace elements and urban gardens. Excerpt:<\/p>\n

    “Cadmium is a contaminant of many manufactured products containing zinc.
    \nAny zinc plating or galvanizing operations and galvanized metal
    \ncontainers sometimes used in horticulture and gardening operations are
    \npotential sources of cadmium.”<\/p>\n

    I certainly don’t think you want to grow vegetables in a cadmium-laced
    \ncontainer. In situations where there is any doubt about safety, I would
    \nrecommend growing ornamental plants in the tubs, and growing edibles in
    \nuntreated wood or clay pots.<\/p>\n

    Container gardening<\/a>, <\/span>Soil contamination<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"

    Is it safe to use galvanized containers (in this case a large galvanized tub like the kind used for watering livestock) in which to grow root vegetables, herbs, etc? I’ve seen some sites sell these for this use, but there are also some postings referring to the potential for ill effects of anti-rust coatings.   You may want to consider both what goes into the galvanizing process, and what could be leaching out of containers as the coating wears down…<\/p>\n

    Continue reading Growing edible plants in galvanized containers<\/span><\/a><\/div>\n","protected":false},"author":4,"featured_media":0,"menu_order":0,"template":"","keyword":[247,511],"class_list":["post-2967","pal","type-pal","status-publish","hentry","keyword-container-gardening","keyword-soil-contamination"],"acf":[],"_links":{"self":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal\/2967"}],"collection":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal"}],"about":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/types\/pal"}],"author":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/users\/4"}],"wp:attachment":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/media?parent=2967"}],"wp:term":[{"taxonomy":"keyword","embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/keyword?post=2967"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}