Split plots into east and west. Required some find/replace and sorting in google spreadsheet to generate insert statements

split_polygons.sql

with foo as
(WITH season1 AS (select id, sitename, geometry as geom from sites where sitename like '%Season 1%' and geometry is not null)
	SELECT
    sitename,
		geom,
		blade
	FROM
		season1 
	CROSS JOIN LATERAL (
		SELECT
			ST_xMin (geom) + (
				ST_xMax (geom) - ST_xMin (geom)
			) / 2
	) AS axis (x)
	CROSS JOIN LATERAL ST_MakeLine (
		ST_MakePoint (axis.x, ST_yMin(geom), 353),
		ST_MakePoint (axis.x, ST_yMax(geom), 353)
	) AS blade
) SELECT
/*	ST_AsText (ST_SetSRID(geom, 4326)),
	ST_AsText (ST_SetSRID(blade, 4326)), */
   sitename,
	ST_DUMP(ST_Split(ST_SetSRID(geom, 4326), st_setsrid(blade, 4326))) as g
FROM
	foo;

Further cleanup and parsing to insert statements are here: https://docs.google.com/spreadsheets/d/1s-kQc3K0h4-hfwMzKOU_zpRXN5loByIpKW8Rvw76mh0/edit?usp=sharing

Based on https://gis.stackexchange.com/q/239801/1239