The effect of sporadic cultivation on seedling establishment on a field abandoned for 1-4 years was investigated in small-plot trials at Prague-Ruzyně in the spring periods 1993-1995. Cultivation included autumn ploughing, spring harrowing and rolling on all plots that were subsequently left to spontaneous weed infestation. Some plots were then mowed or shallowly cultivated in mid-June and late July, others were left without treatment. No significant differences in seedling establishment were found between plots with different treatments. The number of species varied between years, but without a trend to species enrichment or impoverishment. In all years most species were annuals, and species composition did not change in the course of the experiment. The dominant species were Amaranthus retroflexus, Lamium amplexicaule, Echinochloa crus-galli, Chenopodium album, Silene noctiflora and Thlaspi arvense. Species diversity during the experimental years increased due to decreasing dominance of A. retroflexus.