Fill a window box or 8-inch plant pot (or larger) with a soilless potting mix. The pot or window box should have drainage holes in the bottom.
Pour all-purpose granular fertilizer into the soilless potting mixture according to the package directions. Mix the granules into the soil with a hand spade.
Wait until a cloudy day to transplant the ivy, to prevent shock from direct sunlight exposure. Dig up the ivy with a hand spade, getting up as much of the root ball as possible.
Remove the lowest two leaves from the vine. Plant the ivy in the pot so the soil is up to the newest lower leaves. This will stimulate root growth along the vine length.
Water until the soil settles. Set the pot in a spot that gets partial shade.