How to Grow Cucumber

Botanical Name: Cucumis sativus

Plant Type: Tender Annual

The cucumber is a vegetable that to some degree can be considered something of a staple in the Australian diet. In the past, the smaller gherkin types were preferred, but in modern times, the fresh, slicing cucumbers are more popular.  Fortunately, pickles and preserves are once again rising in popularity, which is where the heirloom cucumbers shine.

The cucumber is another annual plant of the family Cucurbitaceae and is believed to have its origins in the Himalayan region of India but was certainly cultivated in Europe during the Roman Empire. It is the fastest and easiest of vegetables to grow, cucumbers are native to Asia and Africa before they were grown by the Greeks, and then adopted by the rest of Europe. Naturally a sprawling vine, they can also be grown up a teepee or trellis to save space.

Cucumbers need a rich soil that does not dry out and has a pH above 6.5. Seeds sprout readily at soil temperatures of 20°C and above. They do best in a well-ventilated and sunny spot. Pick regularly as soon as they are an edible size to encourage flowers and fruit for up to 2 months. Ideal for growing in pots.

Varieties

Cucumber varieties seem to fall into two main groups – those for eating fresh, and those suitable for pickling and preserving.  Selection is largely determined by the intended end use of the fruit, personal tastes, and the environmental conditions under which the cucumbers are to be grown. In general, some varieties are best used for slicing and others for pickling, but many types are very good ‘all-rounders’, and a characteristic which is important to some, is whether the fruit is ‘burpless’ due to an intolerance of cucurbitacin.

Cucumbers can also be divided by their pollination requirements:

• Parthenocarpic Cucumbers are usually hybrids bred for glasshouse growing because they do not require pollination in order to set fruit, but they rarely set seed either, and if they do, it is not viable.
• Monoecious Cucumbers are what most open-pollinated, heirloom varieties are. They produce both male and female flowers (depending on day length) and require pollination from wind, insects, and bees to set fruit.
• Gynoecious Cucumbers produce predominately female flowers and are also hybrids. They should always be planted with at least one Monoecious variety nearby to improve pollination and fruit set.

Cultivation

Growing cucumber is very similar to growing other cucurbits, such as pumpkin, however cucumbers are more sensitive to acidic conditions than other cucurbits, so soil pH should not be below 6.5.

One problem that gardeners may encounter results from the fact that the proportion of male and female flowers produced by cucumbers depends on day length, with more female flowers being produced during shorter days. In southern regions of Australia, this is usually not a problem because soil temperatures are not warm enough for seed sowing until very late spring, so fruiting does not occur until after the summer solstice. In more temperate and northern regions of the continent, with extended growing seasons, this attribute can result in a shortage of fruit during the middle of summer because of the predominance of male flowers.

Sun: Full Sun           

Pollination: Wind, bees, and insects, depending on their type (see description in variety).

Soil: Cucumbers love organic matter in the soil, so the beds intended for production should have lots of well decomposed manure  and compost worked through them. Cucumbers require plenty of potassium to prosper, and utilize greater quantities of nitrogen, without producing more leafy growth.   

Growing from Seed

Sow: Direct, sow after frost.

Ease of Germination: Easy

Germination Temperature: 15°C–35°C.

Germination Time: 7-10 days

Spacing: 70cm-1m apart

Harvest: 52-90 days

Yield: 5-30kg per plant

Seed should be sown when soil temperatures exceed 15°C and are preferably over 20°C. At the latter temperature, seedlings should appear within a week. Being less vigorous than pumpkins, the mounds used for sowing cucumbers can be spaced more closely, about one metre apart. A popular approach to growing cucumbers in small gardens is to encourage the vines to grow up a trellis, making them tidier, easier to manage and harvest.

If using a trellis, sowings can be even closer together at around half a metre. Training cucumber to grow up a trellis is relatively straightforward because once the vines have been initially tied to the trellis, they will grow upwards, supporting themselves by their tendrils.

Maintenance and Additional Care

Bitterness is partially controlled by genetic factors, but some environmental conditions exacerbate it, such as underwatering plants or harvesting fruit late in the season. Some varieties are meant to be harvested when young because, when fully mature, they can be quite bitter.

Companion Planting

Good companions: Beans, Cabbage, Celery, Chamomile, Corn, Dill, Lettuce, Nasturtium, Onion, Radish, Sunflower.

Bad companions: Sage.

Pests and Diseases

Cucumbers are particularly susceptible to powder and downy. Plant is a well-ventilated, sunny position to minimize the likelihood of infection. 

Cucumber can also be badly affected by nematodes, though, some varieties do show some resistance. Crop rotation is the best way to avoid these soil-borne pests. If you suspect a build-up of nematodes, uproot some plants, and check for the presence of numerous lumps or nodules on the roots. If nematodes do build up in your cucumber bed, move the bed to a new location and rest the old bed for a couple of seasons.

Growing in Containers

Cucumbers grow well in containers. Select a premium organic potting mix for vegetables and position your pot in full sun. A trailing vine, position a trellis in your pot if you would like to train them upward, or select a position where the vine can trail over the side without becoming a tripping hazard. Select a large pot at least 30cm in diameter to accommodate 3-4 plants. This will give you the best harvest per square metre. Water regularly and apply a liquid fertilizer with seaweed (such as Ocean Brew) every 3-4 weeks. Try growing bush types, like Cucumber ‘Spacemaster’ when growing in pots.

Harvesting

Cucumbers should be harvested in around 60-70 days from sowing in optimal conditions. Easy to harvest, simply check the recommended length for your variety and carefully cut the cucumbers off the main vine using secateurs or snips. Cucumber lengths differ according to variety, with slicing cucumbers generally growing to around 20-40cm, while ball shaped cucumbers may only reach around 12cm, and Mexican Sour Gherkins reach only 1-2cm. Consume fresh from the vine for optimal flavour.

Seed Saving

Seed Longevity: 5 years

Isolation Distance: 800m

How to Save Seed: Cucumbers grown for seed must be left on the vine until they are mature. This is a lot longer than when they are picked for the kitchen, as cucumbers are usually harvested when immature for consumption. Mature cucumbers will usually change from green to either yellow or orange, depending on the colour of their spines, and become soft.

When harvesting the seed, slice the mature cucumber open lengthways and scoop out the seeds and pulp. Place in an open container to ferment for about 3-4 days before rinsing with water. The viable seeds will sink to the bottom, while the pulp and non-viable seeds will float to the top. Place on paper towel to dry for several weeks prior to placing in an envelope and storing in a dry environment until sowing.  

Tips and Tricks for Success

• in cold climates, fruit can be left to over-ripen on the vine for seed saving.
• if you are growing cucumber along the ground and are concerned about them sprawling all over the garden, then the technique of pinching off the stems, once sufficient fruit have set, will limit their growth.