Objectives  Using garden waste compost and cow manure instead of imported peat to carry out soilless cultivation of Calendula officinalis, expecting to verify the availability of using garden waste compost and cow manure to replace imported peat.

Methods  In all the substrate, 10% perlite and 10% vermiculite (in volume) were added firstly, then the left 80% were garden waste compost and cow manure in mixed volume ratio of 4∶0 (T1), 3∶1 (T2), 2∶2 (T3), 1∶3 (T4) and 0∶4 (T5), and using 80% imported peat as control (T0). The marigold seedlings (Calendula officinalis L.) were grown for 180 days in a greenhouse before sampled. The root and aboveground parts fresh weight, root length, flower number, crown width and plant height of the samples were measured. The importance of these indexes was ranked by RDA analysis.

Results  The development of marigold roots in T0 and T1 treatment were better than that in T2 –T5 treatments; the growth of the aboveground part in T1 –T5 treatments was better than that in T0, with the highest plant height and crown width in T5 treatment, and the most flower number in T2 treatment. The biomass accumulation of marigold of T1 –T5 treatments was higher than that of T0. According to the RDA analysis, the growth, total fresh weight and aboveground fresh weight of marigold were mainly affected by the available P, readily available K, total N, pH, EC and bulk density of the cultivation substrate. The growth of the underground part was mainly affected by the EC, organic matter, total porosity, aeration pore and water holding pore of the cultivation substrate. The main morphological indexes were all the highest under the T1 treatment (0.72).

Conclusions  The mixture of garden waste compost and cow manure is suitable to all right to replace imported peat to make substrates for soilless cultivation of marigold. The best substrate is the composition of 10% vermiculite + 10% perlite + 80% garden waste compost, which has the best chemical and physical properties for the growth of both shoot and root development of Calendula officinalis, thus is recommended as the best cultivation substrate for Calendula officinalis production.