Containerized Virginia pine seedlings were inoculated with Pisolithus tinctorius and grown monoxenically in various substrates consisting of peat:vermiculite amended by mine spoil. Significantly better seedling growth and ectomycorrhizal development occurred when substrates were inoculated three weeks before or at seeding, rather than three weeks after seeding or not at all. Low levels of mine spoil substrate amendments did not affect seedling growth, but did result in significantly lower ectomycorrhizal development. A concurrent open-air greenhouse study showed that mine spoil amendments aided seedling growth more than inoculation did. Mycorrhizal infection was not affected by spoil substrate. Recommendations for the production of mycorrhizal container stock were presented.