Small, round lemon cucumbers (Cucumis sativus "Lemon") feature a thin bright yellow skin. Their color rather than their mild flavor earns the name. Lemon cucumbers produce their first ripe fruits within 65 days of planting when given proper care and growing conditions. These cucumbers are suitable for those living in cooler climates, as the fruits ripen in conditions that are less hot than some other cultivars require.
Cucumbers need full, all-day sun and moist, well-drained soil rich in organic matter to grow well. Lemon cucumbers grow best when temperatures are at least 65 degrees Fahrenheit, so plant them outdoors after the last frost in spring. Although the cucumbers are small, the sprawling plants are large and require a 48- to 60-inch spacing in all directions so they have room to grow. If you are short on space, space lemon cucumbers 12 inches apart along a fence or trellis, and train and tie the vines up the support instead of allowing them to sprawl over the garden bed.
Lemon cucumbers need 1 to 2 inches of water weekly. Water deeply, providing about 1 inch of moisture, at least once a week if there isn't comparable rainfall. The top 6 inches of soil should remain evenly moist at all times; don't allow the plants to wilt from drought stress. Pull any weeds that invade the bed promptly so they don't rob moisture or nutrients from the cucumbers. Covering the soil with a 2-inch layer of mulch suppresses weed growth while helping maintain the moisture in the soil. Apply any mulch after soil temperatures rise to 75 degrees Fahrenheit.
Early and Midseason Feeding
Add 4 inches of compost to the growing area prior to planting, and till it in. Work four to six cups of 10-10-10 fertilizer into the top six inches of every 100 square feet of soil before planting. Fertilize when the lemon cucumbers begin sending out runner vines to give a nutrient boost that will aid flowering and fruiting. Sprinkle ¼ cup of 21-0-0 fertilizer along every 10 feet of cucumber row, applying the fertilizer 6 inches away from the base of the plants and keeping it off the vines and foliage. After fertilizing, water the bed thoroughly so the fertilizer soaks into the soil.
At maturity, lemon cucumbers turn deep yellow and measure 3 to 4 inches in diameter or about the size of a tennis ball. Cut the mature fruits from the stem, taking care not to damage the vine. Lemon cucumber plants will continue to flower and produce more fruits through summer if you pick the mature fruits promptly as they ripen.
Problems and Pests
Powdery mildew and fungal problems are the main diseases on lemon cucumbers. Pull off and destroy badly infested leaves and avoid planting too closely, which can inhibit air circulation, to manage fungal issues. Aphids and spider mites may sometimes feed on the foliage, especially on the underside of broad lemon cucumber leaves. Rinse these pests off with a sharp spray of water. Lemon cucumbers may sometimes develop a bitter flavor. This is caused by drought stress or extreme heat, but proper watering will correct the problem during future fruiting.