Example expand last two columns. Row 10 and columns 1 and 2
python 2
import Tkinker as tk
python 3
import tkinter as tk
btnOff = ttk.Button(self, text = "OFF", command = tc.Off). grid(column = 1, row = 10, columnspan = 2, sticky = tk.W+tk.E)
when you want to use columnspan you will need to make sure sticky W and E selected, similar for rowspan you will need N and S
W
E
N
S