Abstract: A seed cotton dryer system of the parallel flow tower type, having hollow vertically spaced horizontal shelves alternately extending from opposite sides of the tower to locations near but spaced from the opposite side to define a continuing zig-zag cotton flow path from the top to the bottom of the dryer through which the cotton travels impelled by conveying heated air. The hollow interior chambers of the shelves are supplied with heated air to heat the shelf surfaces and thereby facilitate drying, and the vertical spacing between shelves increases in one or more stages below the uppermost shelves providing for higher shelf velocity over the uppermost shelves. Means for recycling the cotton conveying air through the dryer and for monitoring the dew point of this conveying air to proportionately introduce fresh ambient air into the system and/or for monitoring cotton moisture content and automatically regulating heating of the drying air to regulate moisture content levels may be provided.