How do you lime a plot that has a perennial in it? I know your supposed to till after spreading the lime to get good soil contact, but how do you do it with clover or something already standing in the plot?

Best thing I know of is pelletized lime. It's in a granular form similar to fertilizer. Very easy to spread on established plots but it is more expensive than pulverized and takes longer to raise the pH level.

Just let it lay on the surface? I guess when it rains it will slowly leach into the soil.

lime and let lay.

Yes to WT1...

Clovers roots are at the surface, so they would still benefit from a surface spreading of lime. Kura clover is one of the few that spread from underground root system.

Brasicas are heavy uses of calcium, but have a deep tap root, so would not benefit from surface spreading lime.