Grow Your Own Purple Martin Home
Grow Your Own Purple Martin Home
By: Judy Hominick
Much like Jack and his beanstalk, the tenacious tendrils of the gourd vine rapidly galloped up the trellis, captured by a nearby neighbor’s tree and headed for the sky. Not content with its upward march, the vine swooped down to the ground and took off running.
Hard-shell gourds (Lagenaria siceraria) are described as a vigorous vine needing lots of room, but until you have seen a gourd vine in action, it is hard to imagine just how much space it demands. Despite its hoggish needs, though, this vine is fascinating to grow and the resulting gourds can come in a myriad of shapes and sizes and be fashioned into birdhouses, dishes, baskets – even musical instruments.
There is something almost magical about growing gourds, says Marilyn Terry, 1998 president of the Texas Gourd Society (TGS). Growing at an astonishing rate, they seem to appear out of nowhere. "Gourds are called the clowns of the garden."
Hard-shell gourds – not to be confused with the colorful ornamental gourds used as fall decorations – can be treated just like wood once they are thoroughly cured and cleaned. A simple coat of linseed oil applied to the surface gives a wonderful natural finish. More creative sorts can saw, drill or carve gourds as well as paint, varnish or decorate with a wood-burning tool.
PLANTING
The required long, hot growing season fits our Texas weather perfectly. After the last average frost date, plant the seeds about an inch deep in good soil, amended with compost and a little extra fertilizer. Withhold nitrogen once the vines get off to a good start to avoid getting all vine and no fruit. Vine grown on the ground should be inspected frequently for fungus or insect damage. Many growers prefer letting them clamber up a strong trellis so the fruit hangs down where it will grow in a more symmetrical fashion.
When the vine is about 10 feet tall, pinch off the top of the main gourd vine to encourage lateral side branches where female flowers – and future gourds – will form. The flowers open at night and hand pollination is recommended to guarantee good-sized fruit, especially if pesticide use in the garden has reduced the number of moths and other night flying insects. Female flowers have a small "baby gourd" below the stem whereas the male flower has only a long stem.
HARVESTING
Keep plants well watered until fall, then withhold extra water to induce the fruit to ripen. After the vine is completely dead, gourds can be harvested.
"The hard shell gourds will shrivel if picked before they mature sufficiently. People usually leave them until first frost to maximize the chance of getting mature gourds with shells that will hold their shape in the drying process," says Terry.
Gourds can also be left on the vine all winter to dry although seeds may not remain viable. Cure the gourds in a dry, well-ventilated area where air can circulate around the them. Squishy gourds should be thrown out but it is normal and harmless for mold to form on the drying gourds. Depending on the size and environment, gourds can take anywhere from two to three months up to a year to dry thoroughly. Thoroughly dried gourds feel very light and, when shaken, seeds can sometimes be heard rattling inside. When cured, remove the thin outer layer of skin covering the gourd and layers of mold by soaking gourds in hot soapy water for 15 to 30 minutes. When skin is softened, scrape with a dull knife to remove the skin and finish off with some fine steel wool. Rinse and allow to dry thoroughly.
MARTIN HOUSES
The gourds are now ready to be crafted in any number of ways – a popular one is birdhouses. The aptly named birdhouse gourd – or bottle gourd – makes excellent bird abodes for purple martins. In fact, purple martins who live east of the Rockies will only nest in martin condominiums or natural (or artificial) gourds. James R. Hill, III, founder and executive director of the Purple Martin Conservation Association (PMCA), gives these steps for making martin gourd houses.
Choose a cured and clean bottle gourd with a diameter of 8 to 13 inches that is at least 1/4 inch thick. Gourds that are too thin can lead to overheating.
Drill a 2 1/8 inch entrance hole on one side of the gourd. Add seven 5/6-inch drainage holes spaced about 2 inches apart in the bottom.
Drill two sets of hanging holes about 2 inches down from the top of the neck, using a 5/16 inch drill bit. Drill four 1/2 inch ventilation holes, approximately 2 inches below and immediately beneath the hanging holes. Ventilation holes are optional and should only be put on a vertical surface of the neck to prevent rain from getting in.
Clean out seeds and membranes from inside the gourd with a long-handled metal spoon or screwdriver. NOTE – when cutting into a gourd, first pour some water inside the gourd to prevent inhalation of the irritating dust.
Preserve the gourd by dipping it in a conventional wood preservation until saturated. A homeade substitute can be made by dissolving one pound of copper sulfate in a 5 gallon bucket of warm water. Wear gloves and follow package directions. Submerge gourds for 15 minutes. Let dry for several days before painting. Save the copper sulfate solution for redipping gourds every few years.
Paint gourds with two coats of white, polyurethane, high-gloss enamel. Be careful not to clog drainage holes. Although martins are known to nest in gourds painted other colors, white definitely attracts martins the best, says Hill. White also keeps the interior cooler during our hot summers.
Hang six to eight prepared gourds on a pole or line 10 to 20 inches high facing the most open direction, about 30 to 120 feet from human housing. Keep tall bushes, shrubs and vines away from the pole. Here in the south, housing can be placed within 15 to 20 feet of trees and still attract martins but the farther away the better. Use a 24 inch piece of plastic-coated, copper wire through the neck of the gourd and attach to the support structure in two spots to allow the gourd to swing but not twist in the wind. This will make them less attractive to nest-site competitors who will significantly reduce martin occupancy. PMCA recommends frequent checks to oust unwanted birds.
The first average arrival date for adult martins returning to established sites for Texas is from February 1 to February 15, notes the PMCA. PMCA recommends waiting four to six weeks after this date to attract yearling martins who will arrive later and is the only age group who will typically colonize new breeding sites.
Other cavity nesting birds may use birdhouse gourds too small for purple martin use. Wrens will tolerate a swinging house but for other birds, the gourd should be secured to a board or tree. For a house wren, use a gourd that is 5 to 6 inches in diameter with the entrance hole measuring 1 to 1 1/4 inch in diameter placed in the side. Just as with the martin houses, use a wood preservative and drill drainage holes in the bottom. To prolong the life of the gourds, it is best to take down the gourds for the winter once the birds have departed – late August or early September for martins. While wearing a dust mask, remove the nests by sticking the handle of a wooden spoon into the nest through the entrance hole to break it up. Pull or shake out the nest. Rinse out the gourd and let dry. Store where rodents will not chew on them.
Whatever birds you are trying to attract, Maurine Lee with the Dallas County Audubon Society says there is one vital item to remember.
"The most important thing that people forget about attracting birds is to provide water." Birds need the water for drinking and for keeping their feathers clean. In the winter, clean feathers makes for better insulation.
PEEK-A-BOO
Wayne Nagel of Houston goes one step further with his martin gourd houses. Mr. Nagel drills a 3 1/2 to 4 inch diameter hole on the side – 90 degrees from the entrance. Cutting off the top of a wide mouth plastic jar – about an inch or so below the lid – he fits this into the hole in the side of the gourd and then caulks it with latex caulk. The jar top is painted black to prevent light from getting in and then white to keep the interior cool. By lowering the martin house and unscrewing the lid, Mr. Nagel is able to check on the birds and babies without disturbing them. The PMCA reports that nest checks will not cause martins to abandon their nest sites and daily checks are desirable to evict nest site competitors and to check on martin nestlings.
SCARY BEGINNINGS
In the 18th and 19th centuries, Native Americans used dried gourds as purple martin birdhouses, meaning purple martins have been managed by man longer than any other North American bird. It is thought that these early Americans used martins as "scarecrows" to frighten away vultures from meat and hides hung out to dry and to keep crows out of the corn patches.
MOSQUITO DIET?
Alas, while purple martins eat a varied insect diet – including flies, midges, mayflies, stinkbugs, June bugs, grasshoppers, bees, wasps and more – they are not the ravenous devourer of mosquitoes as so often suggested. After an intensive three year study, PMCA reports that it failed to find a single mosquito among the 350 diet samples collected from parent martins bringing food to their young.