To dig up and turn over soil or some body of soil with or as with a spade. A noun or pronoun can be used either before or after "up." You'll want to spade up the flower bed and mix in some fresh compost before sowing the new seeds. The ground was so full of stones and weeds that spading the soil up was an absolute chore.
spade something up
to turn over the soil in a garden plot with a spade. Please go out and spade the garden up so I can plant the potatoes and onions. I will spade up the garden when I have time.