A method for estimating frost hardiness in seedlings ofLarix leptolepisin their first stage of acclimation is demonstrated. Cuttings of the shoot tip were frozen linearly from +2°C to ‐36°C. The viability was determined by TTC‐assay. Data were fitted to a logistic regression model, and hardiness was calculated from the fitting parameters. It was shown that hardiness is influenced by the duration of the fertilizer application period. No effect of the nutrient status of N, P or K in the shoots was found.