The caigua (Cyclanthera pedata), also known as the Inca cucumber, is widespread in Peru, but not widely grown elsewhere. Here is how you can grow this annual climber at home and produce its distinctive horn-shaped fruits.
Origin of caigua
The caigua (Cyclanthera pedata) is native to Peru. Like the real cucumber (Cucumis), it is a cucurbit (Cucurbitaceae), but forms a separate genus. The Incas, the indigenous people of Peru, have been cultivating the plant as a vegetable for hundreds of years. But the cucumber is not only in demand as a food. Peruvian shamans have long known of its medicinal properties. This healing power has now been proven in numerous studies. For example, caigua contains immune-boosting, antioxidant and cancer-inhibiting flavonoids. It also lowers blood pressure, regulates cholesterol levels and helps overweight people lose weight.
Appearance and growth of caigua
The caigua is an annual climbing plant that can grow up to four metres (12 ft) high if placed on suitable trellis. The plant branches out strongly as it grows upwards, making it a good quick screen for balconies and patios. Apart from its five-fingered, hemp-like leaves, its most striking feature is the yellowish-green cucumber fruits, which are about 10 cm (4 in) long and elongated to tear-shaped. The fruits are often covered with spines. Inside the fruit are very firm black seeds embedded in the flesh of the partially hollow fruit. The seeds are only eaten when the fruit is young. The fruit is ready to be harvested towards the end of August. Caigua are self-fertile and produce both male and female flowers. While the male flowers form clusters up to 35 centimetres (14 in) long, the female flowers are single and rather inconspicuous. Both are greenish-white.
Location and soil
The Inca cucumber prefers a sunny and warm spot in the garden as well as humus-rich, nutrient-rich soil with a good water supply. In its natural habitat in the Peruvian Andes, it even grows at altitudes of up to 2,800 metres / 9,200 ft. For this reason, it does not mind lower temperatures. The caigua can be grown both in a bed and in a pot. It can also be grown in a greenhouse. With the latter, you can enjoy a somewhat earlier harvest, but the yield cannot be significantly increased by this protected cultivation.
Sowing and planting caigua
Caigua is one of those plants that germinates very quickly and immediately forms long tendrils. That’s why you don’t have to start pre-cultivation until April. After the last frosts, just a few weeks after sowing, the young cucumbers can be transplanted to the bed or a larger pot. When planting out, make sure the cucumber has a suitable climbing aid. As it produces very long shoots, this should not be lower than two metres. To meet the plant’s high nutritional requirements, it is best to add some ripe compost to the soil when planting.
Like the real cucumber, the caigua is a heavy feeder, which means it has a high nutritional requirement. It is therefore important to supply it with nutrients, especially at the beginning of its growth. Semi-rotted manure or compost is best. Occasional applications of horn meal or an organic liquid fertiliser are also recommended during the ripening period. To meet the high potassium requirements of the caigua, it is best to use comfrey slurry. Cucumbers have a high water requirement as well as a high nutrient requirement. For a good crop, water regularly throughout the growing season.
The caigua grows fast and forms long shoots that are held in place by vines. The shoots need to be moved up the trellis regularly to allow the foliage to dry quickly. This will prevent the plant from being attacked by fungal diseases such as downy mildew.
Mixed culture and crop rotation
When planting in a bed or greenhouse, make sure that no cucumbers have been in the same place for the last four years. Cabbage and corn are also poor previous crops, but pulses, celery and leeks are ideal. To allow the leaves to dry well after rain, it is best not to plant cucumbers in mixed crops, as the other crops may shade the sun-hungry exotics too much.