To measure the soil-to-plant transfer factors (

-fresh) of radionuclides deposited during the growing season of potato, a radioactive solution containing

and

was applied to the soil surfaces in soil boxes 2 d before seeding and three different times during the plant growth. For the pre-seeding application (PSA), radionuclides were mixed with the topsoil (loamy sand and 5.2 in pH). The plant parts investigated were leaves, stems, tuber skin and tuber flesh. The

values of

and

from the PSA were in the ranges of

,

,

,

respectively, for different plant parts. The TFa values from the growing-time applications were on the whole a few times lower than those from the PSA. For

and

, the

values from the early- or middle-growth-stage application were higher than those from the late-growth-stage application, whereas the opposite was true for

. Leaves and tuber flesh had the highest and lowest

values, respectively, in most cases. The total uptake from soil by the four plant parts was in the range of

. In the third year following the PSA, the

values of

and

were

,

and

of those in the first year, respectively, depending on the plant parts. The present results can be used for estimating the radiological impact of an acute radioactive deposition during the growing season of potato and for testing the validity of relevant food-chain models.