Green Plaza Greenhouse, Shōnai Ryokuchi Park (庄内緑地グリーンプラザ 温室)

Shōnai Ryokuchi Park occupies the Odai retarding basin (小田井遊水地) of the Shōnai River, in Nagoya's Nishi ward. The land was designated an air-raid defence green space in 1940, but postwar land reform returned it to farming; in February 1958 it was reclassified as "Green Space No. 3 Shōnai" and development began with the purchase of private plots around the basin. The city-planning project was approved in December 1968 under the theme "water, greenery and sunshine".

The Green Plaza, built on a raised-fill district, opened in April 1986; Japanese Wikipedia and Wikidata give the same date for the opening of the park. The Nagoya Greenery Association (名古屋市みどりの協会) explains that it was carried out ahead of the rest of the country as the model for the "Green Fitness Park" concept, one of the pillars of the national fourth five-year plan for urban parks. It combines an indoor hall for physical exercise with a greenery-promotion facility built around a greenhouse, exhibitions and workshops. The site is now run by a group designated by the city, which includes the Nagoya Greenery Association.

The greenhouse is a faceted glass volume with a glazed roof as well. In photographs published on Wikimedia Commons, one façade forms a tall gable of glass panels with dark mullions, standing on top of a planted bank reached by a staircase; another view shows an angular volume of glass facets with a glazed ridge. Inside, a steel frame carries the glass roof above the planting, according to photographs the park published in January 2017.

The park's website places a herb garden on the second-floor terrace, and its blog mentions a pond at the centre of the greenhouse, which is crossed by a curving path.

The official site states that more than 100 kinds of plants are displayed in the greenhouse, without publishing the list. A post by the park's staff dated 17 January 2017 shows a monstera in fruit, which the text calls rare, and a platycerium; it also notes that it is warm inside and that a pond occupies the centre. On the upper-level terrace, a herb garden completes the greenhouse.

The City of Nagoya describes the Green Plaza as a place for advice and guidance on greenery, with reference materials, exhibitions and workshops. Outside the greenhouse, the park has a rose garden and themed gardens of irises, camellias and rōbai, according to the Aichi prefectural tourism portal.

The greenhouse stands at the main entrance of the park, just south of exit 2 of Shōnai-ryokuchi-kōen station (Nagoya Municipal Subway, Tsurumai Line). Access is free, as for the rest of the Green Plaza apart from the paid indoor hall. A short visit is enough for the greenhouse; the park then invites a walk to the rose garden, the large fountain, the boating pond and the 3.5-hectare lawn, one of the largest in the city according to the managing association. The Green Plaza's closing days are best checked on the park's official website before travelling.