Sphagnum peat (peat), spruce bark compost (compost), peat + perlite (1 : 1, v : v) and compost + perlite (1 : 1, v : v) substrates were inoculated with vegetative alginate-bead inoculum of Hebeloma crustuliniforme, Hygrophorus agathosmus or Paxillus involutus or left uninoculated prior to the addition of Norway spruce seed. Growth and percentage of mycorrhization of bareroot seedlings cultivated in a greenhouse were evaluated after the first growing season. Seedlings grown in peat-based substrates had significantly larger aboveground and total dry weight, but significantly lower mycorrhization percentage than those grown in compost-based substrates. There were no significant differences between fungal treatments (including control) for both the percentage of mycorrhization and growth of seedlings. The artificially introduced fungi were not efficient in mycorrhizal formation – naturally occurring fungi were common in all treatments. However, a significant interaction between substrate and fungus treatments in root dry weight was detected. Hebeloma-inoculated seedlings grown in peat showed the highest value of root dry weight. This fact indicates other possible effects of the fungi on root growth independent of mycorrhization. Growth parameters were negatively correlated with the extent of mycorrhization, indicating allocation of host photosynthates to the fungi. To the best of our knowledge, operational inoculation of Norway spruce seedlings with the test fungi has not been reported previously.