The safest options for producing non-radioactive foods are growing in a green house, sprouting indoors, growing hydroponically indoors, and covering outdoor growing beds during rain storms to prevent exposure to rain water. However, if you plan to continue growing outside under standard conditions, there are things you can do to help protect your soil.
Use Filtered Water to Irrigate the Garden: You can use Zeolite filtered rain water or filtered tap water to water your garden. Zeolite is a mineral formed over time when volcanic ash combines with salt water. It's unique structure allows it to bind up heavy particles such as radioactive Cesium. It is used extensively in nuclear waste clean up. A filter can be made from PVC components, a scouring pad, and Sweet PDZ, which is trade name for Zeolite powder. Sweet PDZ is inexpensive and available at animal feed stores, because it used in horse stalls for reducing odors.
Feed Your Soil: The most important method for reducing soil to plant uptake of radioactive particles, as demonstrated in studies with radioactive Cesium and Strontium, is providing rich healthy organic matter to the soil. Organic gardeners with good composting habits are already a step ahead when it comes to protecting their plants. Personally, I think that the mineral rich additive such as Azomite, a volcanic ash, may also be beneficial, though I haven't found any research to confirm that. Azomite contains minerals and trace elements that improve overall soil function.
Sandy Soils Need Special Attention: Sandy soils, such as the soil we have here in Central Florida, is a factor which increases soil-to-plant uptake of radioactive particles. For this type of soil reducing the relative sand content by adding clay and organic matter is important.
Special Soil Amendments Clay, Calcium, and Zeolite: All soils that are not already rich in clay will benefit from this soil additive. Clay helps reduce soil-to-plant transfer of radioactive Cesium and Strontiun. After clay, Calcium is also important for reducing soil-to-plant transfer of radioactive Cesium and Strontium. Agriculture Lime is one option for supplementing Calcium. From what I understand it is particularly important to supplement with Calcium prior to harvest of leafy green vegetables. The addition of Clay and Calcium is most effective in soils that are low in organic matter. Adding it to healthy rich organic soils will also have some effect in reducing soil-to-plant radioactive Cesium and Strontium transfer, but not as significant as compared to undernourished soils. Zeolite is a mineral that can also be added to soils to reduce the uptake of Cesium to plants. The Japanese Government ordered farmers to add Zeolite to their rice fields after the Fukushima accident in the hopes of preventing radioactive contamination of rice. About 6 grams of Zeolite powder per 1 square foot of is what I calculated to be required after reading acreage recommendations at Acsending Star Seed. I am not sure what the acreage calculations were based on. I added powdered Zeolite to my soil in the form of Sweet PDZ using Joel Tippens' powdered donut method for applying blood meal, bone meal and cottonseed meal. I simply sprinkled the soil with a light layer of Sweet PDZ powder until it was lightly covered like a powdered donut. This soil amendment does not change the soil pH.
Inoculate your Soil with Mushroom Spores: Darkly pigmented fungus have been shown to feed on gamma radiation. Adding mushroom compost to your soil or adding spores from mature melanin pigmented mushrooms, may be able to divert radioactive particles out of your soils and away from your veggies. The area underneath a mushroom cap holds the spores. You can simply tap the tiny spores into your garden beds by patting the top of a mature brown mushroom.
If you are concerned about radiation, but are unsure if you should take preventative measures, you might want to take advantage of free radiation testing tor your home or car air filters or check out the Radiation Network for real time citizen reported radiation monitoring. I purchased a geiger counter kit last week from one of my husband's regular suppliers and we tested our Central Florida (32117) soil and rain water, Hepa filter and various foods. Thankfully there were no issues with anything we tested, but I am still very much acting with precaution.
In my next related blog post I will be sharing about a common wild flower that acts as an indicator for radioactive contamination and share some images of common herbal weeds with very strange mutations from the Northern United States. I'm very curious what you all think of the pictures and if you have seen anything like it before.
Recommendations for Organic matter, Clay, Lime, and Zeolite additives are based on research published in the following articles:
A review of literature on the effectiveness of chemica amendments in reducing the soil-to-plant transfer of radiostrontium and radiocaesium by J. Lembechts. Science of The Total Environment Vol. 137, Issues 1-3, 2-4 September 1993, pages 81-98
Effect of Different Treatments on 85Sr Plant Uptake in Various Soil Types by E. Koblinger-Bokori and P. Szerbin. Proceedings Congress of IRPA Hiroshima: 2000. CD-ROM.
Influence of zeolite on the availability of radiocaesium in soil to plants. by M.A. Shernber and K.J. Johanson. Science of the Total Environment. 1992. Volume: 113, Issue: 3, Pages; 287-295