spawn-brickn. a brick-shaped mass of compost containing mushroom-spawn.
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the world > food and drink > farming > cultivation or tillage > cultivation of plants or crops > cultivation of specific crops > [noun] > mushrooms > compost containing spawn
spawn-brickc1820
c1820 in Loudon Encycl. Gard. (1824) §3413 I shall next give directions how to form spawn-bricks.