Apply gradient color to a whole row

Butanium 

Conditional formatting with color scales, icon sets or data bars only works on the cells with the values; there is no way to extend it to other cells.

You'd have to create multiple rules of type 'Use a formula to determine which cells to format', one for each color.

For example:

• Select the rows you want to format.
• As an example, I will assume that you selected rows 2 and down, and that you want to color them based on the value of column B.
• The active cell in the selection should be in row 2 (the top row of the selection.
• Select Conditional Formatting > New Rule...
• Select 'Use a formula to determine which cells to format'.
• Enter the formula =$B2=10
• B is the column you want to look at, and 2 is the row of the active cell; 10 is the value to check.
• Click Format...
• Activate the Fill tab.
• Select red.
• Click OK, then click OK again.
• Repeat, but with formula =$B$2=20 and a lighter color red, etc.