Cucumber

Sow cucumber outdoors only after the danger of frost has passed and soil has warmed to roughly 60–70°F, since seed germinates poorly below 50°F; plant seeds about an inch deep in hills of several seeds or in rows, later thinning to two or three plants per hill or 8 to 18 inches apart in rows. Seeds can also be started indoors two to six weeks ahead in plantable pots to limit root disturbance, since the taproot is easily damaged when transplanting; harden off seedlings before moving them out, and remove any row covers once flowering begins so bees can pollinate the blossoms.

Cucumbers need full sun and a fertile, well-drained soil rich in organic matter with a near-neutral to slightly acidic pH, along with consistent, plentiful moisture right up until fruit ripens; dry conditions can make the fruit bitter. They are heavy nitrogen feeders and benefit from fertile soil or added nitrogen, and watering should target the roots rather than the foliage to help prevent fungal disease. Vining types can be trained up a trellis or fence to save space, improve air circulation, produce straighter fruit, and ease harvest, though trellised plants lose moisture faster; bush types suit containers of at least a gallon and 8 inches deep. Successive sowings every few weeks extend the harvest, and pinching off new flowers about a month before the first fall frost redirects the plant's energy into ripening existing fruit.

Cucumber beetles, aphids, and squash vine borers are common pests; beetles can be excluded from young plants with fine netting or floating row cover, aphids can be knocked off with a strong water spray, and borers are best removed by hand with crop residue destroyed afterward. Controlling cucumber beetles matters because they can spread bacterial wilt, a disease that requires removing and destroying infected plants; rotating away from previous cucumber ground and improving air circulation by trellising also reduce disease pressure.

Poor pollination can leave fruit misshapen, since female flowers must be fertilized to develop properly. Nutrient shortages show up as foliage symptoms: pale, yellowish leaves signal nitrogen deficiency, while bronzed leaves point to a lack of potassium.

Fruit should be picked green once it reaches the desired size, cutting the stem with a clean, sharp knife or clippers rather than pulling it from the vine. Fruit left to turn yellow has become overripe and tough, and picking often is necessary to keep the vine producing further fruit.

Once harvested, fresh cucumbers keep in the refrigerator for about a week.

Culinary: Cucumber fruit is grown mainly to be eaten fresh in salads or preserved by pickling.

Ornamental: The range of fruit sizes, shapes, and colors also lends cucumber to ornamental use in edible landscaping, and trellising can be used to display the fruit more prominently.

Cucumber's native growing region runs from the Himalaya to northern Thailand, and the crop is thought to have originated in India before spreading into Africa and Southeast Asia. It is not native to North America, where it has long been grown instead as an introduced garden vegetable.