Substantial land areas used for agriculture are located in arid zones including the Arava Valley where large amounts of irrigation water are required for crop production. The Arava valley exhibits limited water resources. The Judea Group and the Kurnub aquifers are the major available water sources for agricultural use in the region. In both aquifers high concentration of radium isotopes were found. Some of the wells exceeding the Israeli drinking water quality regulations (²²⁶Ra = 0.6 Bq•l^-1 and (²²⁸Ra = 0.5 Bq•l^-1). At Shizafon well the ²²⁶Ra concentration is 1.76 Bq•l^-1. Radium availability for plant uptake depends upon soil texture, organic matter content, iron-manganese oxides content, cation exchange capacity and distribution of the radium between the solid phase and the soil solution. Results of radium activity concentrations in soil, water and plant tissues of Cucumber, Melon, Lettuce and Radish, under varied 226Ra in the irrigation water are reported. The concentrations of ²²⁶Ra in the plant tissues of the different crops increase with its concentration in the irrigation water. For all grown crops, concentrations in the leaves are always higher than the concentrations in the edible tissues. The concentrations in the edible tissues of all grown crops are lower than the maximum allowed activity concentration of 10 Bq•l^-1, tentatively set by the Ministry of Health. Radium uptake from soil solution was found to be ruled by environmental conditions (water availability and climate) and it is not plant specific. HYDRUS 1-D simulations of 15 years of crop irrigation with Shizafon water demonstrate that soil surface interactions simultaneously decrease the Ra concentration in the soil solution and significantly narrow its fluctuations during the growing seasons. The Ra activity concentration reaches a steady-state level of 1.65 Bq•l^-1 after 3 and 12 growing seasons in the soil solution and in the drainage water, respectively.