Hi Tallulah please don't try to kill the spiders, try to think of them as a vital and natural insecticide, just think how many flies we'd have if there were no spiders!
How big are they? If they are money spider size, chances are they have just hatched and will gradually disperse, if they are bigger they are probably garden spiders, either way they are harmless. I know its difficult if you have a phobia (if thats the case) i used to be a bit phobic around slugs - sounds silly now, still can't stand them but got used to them cos I like being in the garden so much