Proper harvest timing, handling and curing are important to ensure maximum longevity of gourds. Each year I observe more direct market and wholesale growers adding gourds to their fall sales mix, along with pumpkins, ornamental corn and fall mums. Proper harvest timing, handling and curing are important to ensure maximum longevity of gourds once the consumer brings them home.
Gourds can be divided into 2 major groups, the thicker shelled, often warty, bright and multicolored types in the Cucurbita genus, and the hard, smooth shelled "utility" bottle/birdhouse gourds of the Lagenaria genus. The two types are cured under similar conditions, however the Lagenaria group requires months to cure before it can be marketed, while the Cucurbita group needs only a few weeks to properly cure for market. The Lagenarias when cured properly will last for many years, the Cucurbita types up to six months for best color retention.
The Cucurbita gourds include such types as the crown of thorns, smooth and warted pear shapes, egg types and Turks turban. These gourds are frost sensitive even when mature, so should be harvested before first frost. Usually many fruit become ripe on the vine before frost and can be harvested early. Look for full color development and drying and hardening of the stem and skin before harvesting. Immature fruit generally will not cure well, and should be left in the field.
The Lagenaria gourds come in many shapes and sizes, including the cave mans and Hercules club, dolphin or swan gourd, drum and dipper types. They are more frost tolerant, and because of their longer maturity period will often be found green at first frost. When mature they will begin to change from a bright green to a pale green, eventually to tan.
The stem will also become more rigid. In contrast to the Cucurbita gourds, most fruit, if they have reached a "mature" or "firm" green stage will still cure out well. Ideally if the season allows, it is best to leave them in the field until they are as near maturity as possible. Frost may affect the final tan color, but usually not the integrity of a mature Lagenaria.
Harvest all gourds with 1-2" of stem intact; an intact stem enhances their value. Care should be taken not to bruise or scrape them, and always clip, not tear the fruit from the vine. Freshly harvested gourds can be washed in warm, soapy water, using a soft brush to clean warty types. A light pressure rinse may suffice, followed by a dip in clean water with a household disinfectant, rubbing alcohol, or a light bleach solution (1-2%). This step is important to reduce fungi and bacteria on the surface that can find entry through surface injuries. Curing is a two-step process, involving first a short period for surface drying, and a second longer period for internal curing. Surface drying hardens the outer skin and sets surface colors. Spread out cleaned gourds on a screen or newspapers in a well-ventilated area, partially sunny area, and turn them regularly. Many growers will cut gourds from plants and leave them to dry initially in the field, or in mesh bags. Surface drying should take from a few days to a week. Un-cleaned, field dried gourds should be rinsed and wiped down with a disinfectant solution before continuing with internal curing. Packing boxes and shipping crates are not a good place to cure gourds, as the lack of air movement will result in rotted gourds.
Internal curing takes longer, and a warm (80F), dark and dry location is ideal. Warmth encourages rapid drying, darkness prevents color fading and dryness discourages mold. Artificial heat can be used, but without ventilation it will lead to molding. Cucurbita colored gourds will need 2-4 weeks to final cure, while Lagenaria species may take up to six months. Seeds rattling inside indicate the gourd is fully dry. Under the long-term drying period of the Lagenaria types, it is common to see mold growing across the gourd surface. The mold can leave desirable, unique patterns on the gourd, and its integrity is not diminished. Regular wiping with alcohol or a light bleach solution can discourage this mold growth if a solid tan color is desired. Always monitor the drying operation so that shriveled or rotted gourds are removed, this is especially important for colored cucurbita types, and when potentially immature fruit may have been harvested in the rush to beat frost.
Following curing, gourds can be waxed, laquered or painted. For colored types, well-cured gourds may last 3-4 months without this treatment, while coating with wax or varnish will help extend storage life and color retention of the gourd another 3-4 months or more. Paste wax will provide a soft luster to the gourd, while varnish or laquer adds a greater shine. Gourds can be sanded smooth and painted as well, which can greatly extend the life of the Lagenarias that are used outdoors, such as for a birdhouse.
Seeds from both types can be saved successfully, however keep in mind that any Cucurbita species (and there are many, including squash and some pumpkins) can inter-cross freely. However the Lagenarias and Cucurbitas will not cross. Random crosses within species will result in progeny generally not true to the parent, but some interesting, and unique gourds types may occur from your breeding efforts.
Virginia Vegetable, Small Fruit and Specialty Crops, August 2002; Volume 1, Issue 8
Tony Bratsch, Extension Horticulture Specialist, Virginia Tech
Virginia Cooperative Extension, www.ext.vt.edu.