TABLE 1.

Coded and un-coded factors for each treatment of the response surface analysis experiment investigating the effect of nitrogen (N), phosphorus (P), and potassium (K) rates on cannabis production in deep-water culture.

	Coded factors			Un-coded factors (mg L–1)
Treatment	A	B	C	Na	P	K
1	–1	–1	–1	120	40	120
2	+1	-1	–1	250	40	120
3	–1	+1	–1	120	80	120
4	+1	+1	–1	250	80	120
5	–1	–1	+1	120	40	280
6	+1	–1	+1	250	40	280
7	–1	+1	+1	120	80	280
8	+1	+1	+1	250	80	280
9	–1.682	0	0	70	60	200
10	+1.682	0	0	290	60	200
11	0	–1.682	0	180	20	200
12	0	+1.682	0	180	100	200
13	0	0	–1.682	180	60	60
14	0	0	+1.682	180	60	340
15	0	0	0	180	60	200
16	0	0	0	180	60	200
17	0	0	0	180	60	200
18	0	0	0	180	60	200
19	0	0	0	180	60	200
20	0	0	0	180	60	200

^aN-NH₄ + N-NO₃.