Well, if I did my math right, you'd have to fudge either the sizes or the distances.
The radius if the Solar System (Sun to Neptune) is approx 4.545x10^12 meters.
Scaling that down to 50 meters, gives you a ratio of 9.09x10^10:1
The largest planet, Jupiter has a radius of 7.1492x10^7.
Scaling that down to your 50m garden would mean Jupiter has a radius of 7.865x10^-4m or 0.7865mm.
Anyone, please confirm/correct my math.