To start, get ahold of a shallow dish to hold your home-made nectar. You can use the drip-catching saucer from a hanging planter, or a ceramic or glass plate. Or use things you already have around the house, like a plastic picnic plate or the lid from a wide jar. You might want to paint its concave side with splashes of red, orange, and yellow, or glue on cut-up bits of kitchen sponge in those colors, to make the feeder resemble flowers.
Next, you need a way to hang up your feeder. You can punch three equidistant holes around the rim such that the contents of the dish don’t run out. Thread baling wire through these holes to meet at a point above the center of the plate, and hang the feeder from this point. For materials too tough or too easily cracked to pierce, you can use hemp twine or clothesline to make a macrame-style hanger (or purchase one at a garden-and-greenhouse supply store).
You can add a rain shield by running the baling wire or macrame hanger through a larger plate suspended upside down a foot or so above the feeder plate. Another optional feature you can add is a covering of fiberglass window screening to keep other insects out. Secure the screening to the rim with a few paper-clamps. Just make sure the screening isn’t so far away from the food that a butterfly’s proboscis can’t reach it.
Butterflies like the sun, so you’ll want to hang your feeder where it’ll receive direct sunlight at least for part of the day. You’ll also want to make sure you can reach it safely to fill it. If you can’t reach it with a stepladder, it’s too high. Make sure the ground below the feeder is flat so that the stepladder won’t wobble or fall down with you on it.
Squirrels might get a little too interested. To deter them, hang your feeder plate well below any tree branches and well away from tree trunks. This will make it difficult for them to leap onto the plate. Some will try it, regardless; if your feeder is sturdy enough, it’ll tip the squirrel off but not fall apart under the impact.
The easiest faux nectar to make is a soup of rotting fruit. Cut up any fruit that’s getting over-ripe, mushy, or bruised, and mix this with sugar and/or molasses. You can add a can of beer, too, or a few cups of orange juice. Let this mixture sit in a sealed container for a few days, and pour it into your feeder as needed. You can sometimes acquire ingredients from your local grocery for very cheap or even free, since they often throw out fruit that’s past its prime.
Some species of butterflies prefer fresh to fermented. You can try placing slices of bananas, strawberries, or other raw fruit in your feeder and pouring a little water or juice over them to keep them from drying out. Since butterflies taste with their feet, these chunks of fruit make tasty places for them to perch.
You can also make a nectar similar to the kind used in hummingbird feeders by boiling four parts water to one part granulated sugar. Let it cool, then pour it into your feeder plate. Try lightly coloring this liquid red or orange with food coloring.
Additionally, you might reserve one of your feeder plates for “puddling”–when butterflies sip water from puddles or mud patches. Fill your feeder with sand or mud or a mixture of the two. Add just a pinch of salt. Over-water this mixture a little, so that a bit of liquid stays on top. You can place a few stones in the mud or sand for perching. You might place this feeder in a bucket lid set into the ground instead of in a hanging plate.
Make sure to clean your feeder every few days with hot water and a little bleach to keep mold from taking over. Rinse thoroughly, rehang, refill, and watch the butterflies rediscover your offerings. With very little effort and expense, you’ll keep them flocking to your home for years to come.