Gherkins, often referred to as cornichons when pickled in the French style, are a specific variety of small cucumber cultivated primarily for preservation. These pickling cucumbers are distinctly different from the long, smooth-skinned slicing varieties found in most grocery stores. Gherkins are characterized by their petite size, typically bumpy or spiny skin, and firm flesh that holds up exceptionally well during the pickling process. Cultivating these small fruits requires specific techniques concerning site preparation, daily maintenance, and precise harvesting timing.
Preparing the Site and Sowing Seeds
Gherkin plants thrive in locations that receive full sunlight, needing a minimum of six to eight hours of direct sun exposure daily for optimal growth and fruit production. The soil must be rich, well-draining, and heavily amended with organic matter like compost or well-rotted manure, which should be worked into the top six inches of the planting area. Cucumbers prefer a soil pH that is slightly acidic to neutral, ideally ranging between 6.0 and 6.8.
Timing the planting correctly is crucial, as gherkins are highly sensitive to cold temperatures and frost. Seeds should not be direct-sown outdoors until the soil temperature consistently reaches 70°F or higher, and all danger of the last frost has passed. Planting earlier can be achieved by starting seeds indoors about three to four weeks before the intended outdoor planting date. Whether direct sowing or transplanting, place seeds or seedlings approximately one-half inch deep in the soil.
For direct sowing, plant seeds about four inches apart initially, which allows for thinning later to achieve the best spacing. Once the seedlings develop their first set of true leaves, thin them to a final spacing of six to twelve inches apart, selecting only the healthiest plants to remain. This spacing ensures proper air circulation and reduces competition for nutrients in the soil.
Daily Maintenance and Vertical Support
Consistent and deep watering is a requirement for successful gherkin production, especially once the plants begin to flower and set fruit. The goal is to keep the soil evenly moist but never saturated, as drought stress causes bitterness in the fruit and can halt production. Applying a thick layer of organic mulch around the base of the plants helps to regulate soil temperature and retain necessary moisture.
The nutritional needs of the plant change significantly once flowering begins, requiring a switch from a balanced feed to a high-potassium, low-nitrogen formulation. Nitrogen-heavy fertilizers will encourage excessive leaf and vine growth at the expense of fruit development. A fertilizer with an NPK ratio like 5-10-10 or a liquid tomato feed, which is naturally high in potassium, should be applied every one to two weeks to support heavy fruiting.
Vertical support is highly recommended for vining gherkin varieties. Installing a sturdy trellis, cage, or netting at least six feet tall before planting offers numerous benefits. Growing the fruit vertically improves air circulation around the foliage, which helps prevent fungal diseases like powdery mildew. Furthermore, it keeps the developing gherkins off the damp soil, resulting in straighter, cleaner, and more uniformly colored fruit.
Harvesting and Storage for Preserving
The timing of the harvest is the most important factor when growing gherkins for pickling, as the window for perfectly sized fruit is quite short. Gherkins must be picked when they are immature and very small, typically measuring between one and three inches in length. Harvesting at this size ensures the characteristic crisp texture and prevents the fruit from developing large, watery seeds and a tough skin.
Harvesting must occur daily or at least every other day, as the fruit can rapidly grow past the ideal pickling size. Allowing gherkins to mature fully on the vine signals to the plant that its reproductive cycle is complete, causing it to slow or stop producing new blossoms and fruit. This frequent picking encourages the plant to continue flowering and producing a greater overall yield.
To prevent damage to the vine, which can be easily injured, the fruit should be removed using a sharp knife or small pruning shears. Cut the stem just above the gherkin, leaving a small piece of stem attached to the fruit, which can help keep the gherkin firm during the pickling process. Immediately after picking, fresh gherkins that cannot be pickled right away should be washed and then stored unwashed in the refrigerator. Wrapping them loosely in a plastic bag or storing them in a crisper drawer will maintain their crispness for a few days until enough have accumulated for a full batch of pickles.
Identifying Common Pests and Diseases
Gherkins, like all members of the Cucurbitaceae family, are susceptible to a few common garden pests and fungal diseases. Powdery mildew is a frequent issue, appearing as a white, dusty or flour-like coating on the surface of the leaves, especially later in the season. Proper plant spacing and trellising help increase airflow, which is the best preventative measure against this fungus. Organic treatments include spraying the affected foliage with a solution made from baking soda and mild liquid soap or a diluted milk mixture.
Insect pests like the striped cucumber beetle and the squash bug can cause significant damage to gherkin plants. Cucumber beetles are small, yellow insects with black stripes or spots that feed on leaves and flowers and can transmit bacterial wilt. Squash bugs are brownish-black, shield-shaped insects that suck the sap from the leaves, causing them to yellow and wilt.
For young plants, the use of floating row covers can physically block both types of pests until the plants are large enough to withstand minor feeding damage. Hand-picking adult squash bugs and destroying their reddish-brown egg clusters, found on the underside of leaves, is an effective organic control method. Applying neem oil or insecticidal soap can manage populations of both cucumber beetles and squash bug nymphs, especially if applied thoroughly to the undersides of leaves.