Cucumbers are not a particularly important food crop, but they do bring some interest to food dishes and provide refreshing taste to summer salads. Cucumbers can be eaten raw and sliced into salads, pureed into soups or chopped and cooked into Indian-style vegetable dishes. Additionally, young parts of the plant (leaves, shoots, seeds and roots) are also consumed as food. Cucumber do very well in hot climates, with plenty of water for fruit set, and new cultivars are highly productive and only require one or two plants to provide enough for a family.
The present day cucumber is thought to have its origins on the foothills of the Himalayas from the wild Cucumis hardwickii. The plant has been cultivated in India for 3000 years, from Cucumis hystrix, and was introduced to ancient Egypt, Greece and Rome. Several varieties of cucumbers can be found worldwide today with three main varieties; slicing, pickling and burpless cucumbers.
Cucumbers (including gherkins and melons) belong to the same family as the squash and pumpkins, the Cucurbitaceae, but cucumbers belong to a different genus, namely Cucumis. The most widely cultivated species of cucumber is Cucumis sativus. Several wild cucumbers are also available, but are not commercially grown, specifically the native African cucumbers. Here is a quick run-down of each;
Cucumis sativus – three main varieties. Slicing cucumbers are eaten raw and unripe (green). These are mainly used in salads and cooked dishes. Pickling cucumbers are pickled for flavour and are shorter and thicker than slicing cucumbers. Burpless cucumbers are sweet, nearly seedless and have a thinner skin. This makes them more popular for raw consumption, but need to be grown in a greenhouse to prevent pollination by insects.
Cucumis metuliferus – the African horned cucumber. This is a round variety with large spines. It is eaten when fully ripe (bright yellow-orange) and is supposed to have notes of banana, melon and citrus – but I highly disagree (see later for more details).
Cucumis hirsutus & Cucumis quintanilhae– two African varieties, but largely undescribed.
Cucumis hemifructus – another African species, known as the ‘Aardvark cucumber’. It is also known as the Kiwano, melano, African horned melon, horny cucumber, hedged gourd or English tomato (who knows what’s on with the last name). This is a round variety with large spines. The fruits can be eaten young, mature green or when fully ripe (bright yellow-orange). It is used mainly in desserts and is supposed to have notes of banana, melon and citrus – but I highly disagree (see later for more details J). It originated in Africa, the Kalahari desert. It was introduced to Australia, where it became a weed, and is now cultivated in California and New Zealand.
Cucumis melo – that’s the melon. Not fond of melons, but I imagine the growth requirements are largely the same as cucumbers.
Cucumis anguria – the burr gherkin. A West African species that cannot be interbred with the commercial gherkin, but it can be eaten and pickled.
Cucumis myriocarpus – the paddy melon, a mostly inedible species from Spain.
Cucumis zeyheri – an African species, very bitter and inedible. Also known as the wild cucumber or bitterappel (again Afrikaans for “bitter apple”).
As you can see, most of the other cucumber species are bitter and inedible. This is due to a compound found in cucumbers, known as cucurbitacins. The cucurbitacins are cytotoxic (causes death to cells) and are often poisonous to livestock, we (humans) perceive this as a bitter taste. Cucurbitacins are species related, where Cucurbitacin C is found in Cucumis sativus, and Cucurbitacin A in other species of Cucumis.
The burpless cucumbers are parthenocarpic, meaning that they can produce fruits without pollination/fertilisation. This prevents the production of Cucurbitacins that results in bitter tasting fruits and hence they are grown in greenhouses to prevent pollination. The varieties of slicing cucumber that I have (and the African horned cucumbers) do not produce fruits without pollination. Thus I will be discussing cucumber pollination hereafter.
Cucumbers are grown outdoors in regions with warm climates. In temperate or colder regions, cucumbers are grown indoors under glass- or greenhouses (and thus it would be better to get the burpless varieties, since pollinators are not available).
Cucumber seeds are sown directly into the ground, or can be started indoors and moved out to the garden once the plant has 3-4 leaves and the threat of frost is over. Seeds should be sown in soil that has reached at least 16oC (60oF), this means well into spring or started indoors under a cloche (this can be an overturned transparent plastic bowl or bottle).
There are two main ways to grow cucumbers:
1 cucumber) Over the soil. This is where the cucumber vine is left to trail over the ground. Problem with this is that fruits either rot on the wet ground or they become hard and yellow on the side that is in contact with the ground. This can be prevented by placing straw or plastic underneath developing fruit.
2 cucumber) Trellis. Many different trellises have been fashioned for cucumbers both in pots and directly in the garden. I have my trellis propped diagonally against the wall with enough space between the wall and the trellis for the cucumber vine to grow and bear fruits. This negates the soil contact issue and also saves soil space for some other vegetables!
The cucumbers will start to produce 1-2 months after sowing. Many standard cultivars are very prolific and two plants produce about 6 cucumbers (a good 30-25 cm) every two weeks. You can also stagger the crop, by planting the second set cucumber(s) one month after the first or after the first set has started to flower.
I do not limit the amount of cucumbers on a plant, since they have such a quick turnaround time for fruit set and increased soil fertilisation (every two weeks) during fruiting should help it along. Pinch out the growing tip (with your fingernails or cutters), two leaves after the first fruit – this will encourage a more bushy nature with more fruiting side-shoots.
The first flowers produced are males, after which female flowers emerge (small cucumber behind the flower). If you have a lack of pollination (our bees only have eyes for the basil flowers!) – then the flowers need to be pollinated by hand. The female flowers are easily pollinated by using a soft paint brush, scoop out some pollen (yellow dust) from the male anthers and deposit on the female stigma. The male anthers have a single yellow structure, whereas the female sigma is a light yellow three-lobed structure, see Squash for more details on hand pollination. For burpless varieties, remove the males, since the females develop fruit without pollination.
The fruits will hang from the trellis as they swell, you can support them with thick twine tied around the stems several times- this prevents stem breakage.
Cucumbers can be harvested when small (10 cm) or fully swollen (30 cm). Some cucumbers have spines, but these are easily removed by scraping with a butter knife. Cucumbers do not keep well after harvest. The shelf life can be extended by refrigeration (in a plastic bag with a few drops of water to prevent shrivelling), will keep for about a week.
Seed Collection & Storage
Cucumber seeds are harvested from botanically ripe fruits. This is the same for squash. Botanically ripe cucumbers are yellow and mushy, bitter and inedible! The seeds are extracted and the pulp washed from the seeds. You can also ferment the seeds, but all I manage to get is germination and not fermentation – so pick mushy fruits that have already done that for you. The seeds can be stored in labelled glass jars for up to 5 years.
I have the Starke Ayers Ashley variety – produces thick, up to 30 cm cucumbers and is very prolific. Some spines are present.
African horned cucumber – I decided to try this. The plants grow very well –trailing all over the place, but they are slow to produce fruits. The fruits are horrible – very bitter – I was not impressed especially after being lied to about how nice they are! They do have a large ornamental value, for those interested in some strange looking plants, but as an edible crop – no.
Bitterappel – We have a bushveld next to our house on the same property. We find all kinds of interesting things in there. This year, for the first time that I noticed, we came across some wild cucumbers. I first had them wrongly identified as there is loads of confusion on the internet about the African cucumbers. So I thought I till give it a sampling (this was before sampling the commercial African horned cucumber) and it is so horrible that the bitterness will even stick to water,Eish! After that unpleasant experience, I had tons of suspicion about the African one – so did not have such a humongous bite of that! The other problem is that they smell so wonderful, much like a banana melon, but Egh! So, I think it is safe to say that these wild cucumbers are likely Cucumis zeyheri and that I won’t be planting any African cucumbers again.
On that note, I think it was a bunch of people who have the genetic defect for tasting bitterness that wrote the descriptions! Yes, about 70% of the population can taste bitterness, whereas the other 30% have a mutation in the gene and they cannot taste bitterness – and will likely have more appreciation for ‘other’ flavours of bitter cucumbers! Apparently there are non-bitter cultivars … so maybe I got cheated instead!
Last note, I had some lemon cucumber seeds, but got confused about whether I planted them or not. Thought that some of the African ones were lemons until they started fruiting – oh the horror! J After a second round of seeding I realized that the lemons aren’t all good to eat, some of them are bitter too! Not as much as the African ones, but there are one or two that come out bitter. Besides I don’t taste the difference between them and normal cucumbers (maybe a bit sweeter?) – so I decided to stick to my Ashley!