Cucamelon and Achocha: two tough climbers for the fence

There is that moment in high summer when the classic garden cucumber already shows powdery white leaves and you wonder for the third time whether spraying is still worth it. That is exactly where two little-known exotics shine: the cucamelon and the achocha. Both climb the fence willingly, turning it green and screening, and one bears fruit that looks like watermelons in doll size. Anyone who has snacked a handful of these mini cucumbers straight off the vine understands why they are addictive.

Why two exotics instead of yet another cucumber

The ordinary cucumber (Cucumis sativus) is a wonderful vegetable, but it is also a diva. Powdery mildew, downy mildew, cool nights where it sulks and lets its leaves droop. The two climbers in this piece are made of sterner stuff. They come from regions with rough weather swings and keep bearing stubbornly when the classic cucumber has long given up.

Both belong to the gourd family (Cucurbitaceae), but neither is a true cucumber. That is the good news for anyone who has despaired over mildew: the typical cucumber diseases bother them far less. And because they grow so vigorously, you only need one or two plants to green a whole stretch of fence.

The cucamelon: watermelon in miniature

The cucamelon (Melothria scabra) goes by several names: Mexican sour gherkin, mouse melon, cucamelon. All mean the same dainty little fruit, barely bigger than a grape, with a pattern that is startlingly like a watermelon. The taste, though, is pure cucumber, with a fresh, slightly lemony kick at the end.

The plant itself is delicate and fine. Thin tendrils, small yellow flowers, filigree foliage that threads effortlessly through a trellis. It grows far less bulky than a garden cucumber and therefore also fits a large container on the balcony, as long as there is a support to climb. A single well-tended plant will give you a handful of fruit again and again over weeks.

Harvest while they are crunchy

Harvest the fruits best when they are about 2 to 3 cm long and still firm. Wait too long and they turn soft and the seeds grow larger. They are snacked raw, skin and all, straight off the vine. In the kitchen they do brilliantly pickled like cornichons, or chopped small into a summer salad, where their citrus note comes as a surprise.

The achocha: the stuffable horn of the Andes

The achocha (Cyclanthera pedata) is the tougher, wilder character of the two. In its home, the Andean countries from Peru to Bolivia, it is called caigua or achocha and has been cultivated for centuries. The fruits are pale green, hollow, slightly curved like little horns and carry soft, harmless spines. Inside sit black seeds in an airy chamber.

The taste of young fruit recalls a mix of cucumber and green pepper. Harvested young they are crunchy raw, riper they are usually steamed, fried or indeed stuffed: because they are hollow, they can be filled like small peppers with minced meat, rice or cheese, a classic of Andean cuisine. The plant climbs strongly and persistently, far more vigorously than the dainty cucamelon, and therefore covers larger fence areas too.

Vigorous and grateful

The achocha is one of the most low-maintenance climbers in the vegetable garden. It shrugs off cooler summers, sets fruit into autumn and is barely bothered by pests. A trellis of at least 2 m and a sunny spot are enough for it. In mild locations it even self-seeds and reappears in the same place the following year.

How to raise and plant out both

The process is almost identical for both exotics and follows the rhythm of every heat-loving crop: start indoors, harden off, out after the Ice Saints.

1. Sow from mid-April · CW 16

   Place one to two seeds per pot about 1 cm deep in seed compost. At 20 to 24 degrees they germinate within one to two weeks. The achocha often germinates a little more stubbornly, so be patient.

2. Grow on bright and warm

   Once the seedlings are up, they need the brightest spot in the house, or they get leggy. A south-facing window or a grow light keeps them compact.

3. Harden off from early May

   Put the young plants outside during the day for about a week before planting out, in a sheltered spot, so they get used to sun and wind.

4. Plant out after the Ice Saints · CW 18 to 22

   Only when there is no more risk of night frost, usually from mid-May, do they go to the fence or trellis. Keep about 40 to 50 cm between plants.

5. Guide the tendrils

   In the first weeks you help the young shoots onto the mesh a little. After that both climb on their own and find their way.

Site, soil and care through the year

Both climbers are heavy feeders and reward a well-prepared soil with lush growth. Work in mature compost before planting, which usually covers the base supply for half the season. During the main growing period from July to August · CW 27 to 35, both enjoy an extra feed, such as diluted nettle brew.

The most important factor is water. Gourds with their large leaf areas transpire a lot, and the cucamelon in particular repays drought stress with bitter fruit. Water deeply in the morning rather than a little every day, and mulch the soil so it holds the moisture. The achocha copes with short dry spells better than its dainty colleague, but it too bears best under even moisture.

A trellis is a must. Both want to go up, not crawl over the ground, where the fruit would rot. A wire mesh fence, an espalier or a simple net between two posts will do. Reckon on 2 to 3 m of height for the achocha, while the cucamelon stays a little daintier at around 2 m. Set both side by side and you get a lovely green wall with two kinds of harvest.

Harvest, kitchen and seed saving

With the cucamelon the rule is: the younger, the crunchier. Harvest as soon as the fruits are grape-sized and firm, then the yield is highest, because regular picking prompts new flowers. Harvest the achocha young for eating raw or a little riper for stuffing and steaming. Both keep bearing until the first frost.

If you want to sow again next year, let a few fruits fully ripen at the end of the season. With the achocha they turn soft and the black seeds inside dark and hard. With the cucamelon you let a fruit go overripe and slightly wrinkled. Extract the seeds, dry them, store them cool and dark, and there is your seed for next year. In mild locations both also self-seed.

If the appetite for unusual climbers has got you, you will find more of them in our magazine. And if you prefer the classics, the tried-and-tested salad and pickling cucumbers are for you.