It depends on the seeds, for one thing, and on the food colouring used for another.

It can happen, as this example shows: You can plant cress seeds and add food colouring to end up with a different colour for the plant. And a flower, for example, that is already grown, will often change colour if you add food colouring to the water for a few days.

Also, there is a practice called colour feeding, which involved feeding small birds, such as canaries, on different coloured foods to eventually change the colour of their feathers, and if it works on canaries why not on some plants?

Growing seeds with food colouring has sometimes been tried as a school experiment, but the results are very variable as it does depend on the colouring, when it was added and the type of plant. You can see an example here.