Abstract: Healthy potted alfalfa plants grown in a greenhouse are commonly used in pathogenicity tests. The growth of such test plants is strongly influenced by the environmental conditions, especially nutrient supply. In order to determine the most suitable nutrient solution for the healthy growth of potted alfalfa plants, two-day-old seedlings were transplanted into pots filled with sterilized soil, and supplied either compound fertilizer (CF), Hoagland's solution (HS), tap water (TW), or distilled water (DW). Plant growth status, plant heights and other data were recorded during the next four weeks, and biomass of seedlings at the end of the fourth week was determined. It was found that CF was obviously superior to other treatments; in this treatment, the plant growth status was the healthiest, and the leaves of the CF plants had no discoloration or dryness. Moreover, the growth rate of these plants was up to 1.15 cm·d^-1 with on average 4.28 branches per plant whereas the growth rate of TW plants was just 0.28 cm·d^-1 with no branches formed. The leaves of the TW plants were more or less dry or had even died by the end of the 4th week. Hoagland's nutrient solution proved inferior to the plant growth fertilizer. There were no significant differences between the DW and TW plants. Compared with TW plants, plant height, fresh weight, ground dry weight, root fresh weight, root dry weight, root surface area, root diameter, numbers of leaves and internode numbers of CF plants were increased, respectively, by 256%, 731%, 655%, 384%, 445%, 101%, 27%, 84% and 112%, with P<0.05 in all cases. For comparison, corresponding plant size increases for HS plants were 88%, 117%, 188%, 105%, 117%, 40%, 7%, 30% and 40%, respectively (P<0.05).

Key words: Medicago sativa, compound fertilizer, Hoagland's nutrient solution, tap water, plant growth status