IMPAIRMENT, RESTRUCTURING AND OTHER - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		27 Months Ended
	Dec. 28, 2024	Dec. 30, 2023	Dec. 30, 2023
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, long-term	$ 7.7
Severance charges	9.5
Loss on exchange of convertible debt instrument	7.0
Employee Severance and Impairment Of Property, Plant, And Equipment
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		$ 3.7
Hawthorne
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	3.7		$ 300.9
U.S. Consumer
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	1.4		59.8
Corporate Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		2.4	25.1
Other
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			$ 2.9
Cost of sales—impairment, restructuring and other \| Hawthorne
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		7.7
Cost of sales—impairment, restructuring and other \| U.S. Consumer
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		2.0
Impairment, Restructuring, And Other
Restructuring Cost and Reserve [Line Items]
Gain (loss) on resolution of dispute	12.1
Impairment, Restructuring, And Other \| Hawthorne
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		0.3
Impairment, Restructuring, And Other \| U.S. Consumer
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		0.8
Operating expenses
Restructuring Cost and Reserve [Line Items]
Loss on exchange of convertible debt instrument	$ (7.0)	$ 0.0