depends how big you want the end result and how quickly realy.

You're a bit late for potatoes so I would concentrate on carrots if I were you!
Carrot seed is extremely small so what tends to happen is you sow them thinly in rows approx six inches apart then thin out the rows as the carrots develop.
A tip to avoid carrot fly is to only thin out on damp mornings, this way the flies can't smell the carrots so easily.

Cheers folks, think I will stick to carrots. Thinking of planting lettuce, cabbage and sprouts today. Not very exciting I know lol

well at least you will get a crop look on the bright side well lettuce you will im not sure about the others .