JÜrg Steiger's famous temperate PINGUICULA collection

Jurg Steiger is a well-known botanist, talented author of numerous publications and articles and the Precursor of the culture of Temperate Pinguicula with his famous Steiger wall. He lives in Switzerland, in Bern (see Map).

Here is the presentation of the original dripping wall by Jurg Steiger : Pinguicula (lentibulariaceae) : The cool climate species of the northern hemisphere - morphology, biology, cultivation; a presentation he gave in the Second conference of the International Carnivorous Plant Society, Bonn, Germany, May 30 - June 1st, 1998 :

"I live in Central Europe, in a suburb of Bern, at 600m, 25km north of the Prealps. Summer maxima reach+30°C, winter minima -15°C. I grow most Pinguicula on vertically positioned PVC sheets (20mm thick) equiped with horizontal 'lamellas' put into 45° angle slits. The vertical distance from lamella is 40mm. The lamellar sheets are fixed within a greenhouse along the north-east wall of his house which is surrounded by some trees on the east side. From mid-December till mid-January the plants do not get any sun at all. In summer they get 1-2 hours of sun in the morning when the sun appears between the trees and the projection of the roof. A timer allows water to trickle from time to time though the substrate which never be too soggy (to avoid rootness). The greenhouse is divided into three climate compartments. In all three compartments there are fans to produce wind for 15 minutes each hour and ultrasound fog machines to produce high air humidity.    

Compartment A is kept open all spring, summer and autumn but closed and slightly heated in winter to avoid frost (winter temperature +1° to +8 °C). In this compartment I grow the Isoloba species (P. crystallina/hirtiflora and P. lusitanica).  

Compartment B is kept open all the year except in winter days with heavy frost. In light frost it is open allowing the substrate to get slightly frozen. In this compartment I grow P. vallisneriifolia, P. longifolia ssp. caussensis and subsp. reichenbachiana, P. dertosensis, P. mundii and P. macroceras ssp. nortensis.

Compartment C is kept open all winter except in heavy frost but closed from spring to autumn. It is cooled with a professional cooling system allowing e.g. a night temperature of +5°C and a day temperature of +10°C even if it is 25°C or more outside. Household air conditioners are useless as their compressor is not constructed for temperatures below 18°C. In this compartment J grow P. alpina, balcanica, corsica, fiorii, grandiflora, leptoceras, longifolia ssp. longifolia, macroceras, nevadensis, ramosa and vulgaris. These species are infested by fungi if not exposed to an ultraviolet source.

From mid-June to the end of August P. variegata and villosa (and hopefully in near future P. algida) are grown in a horizontal refrigerated box similar to those used in food markets. As the air humidity is constantly reduced due to the condensation at the surface of the cooling pipes, the entering cooled air must be rehumidified to at least 70% relative humidity. From the beginning of September to the beginning of June the named species are kept in a deep freezer at -15°C."