How To Grow Cucumbers

Why not plant an exotic variety of cucumber in your garden this season and perk up those summer salads! Cool, crisp cucumbers from the garden are perfect in summer salads - or on their own with sour cream and fresh dill.

Types of Cucumbers

If you go by your local produce section, you might think 'a cucumber is a cucumber'. And well, you'd kind of be wrong - as there is a bewildering array of different cucumber types, with some types overlapping (e.g. some cucumber varieties are bred to be good for both slicing and pickling).

Standard cucumbers are often called slicers. Slicers are usually 6-9 inches (15-23 cm) long, but may be as short as four (10 cm) and as long as 14 (36 cm) inches.
"Burpless" varieties have been bred to avoid a common side effect.
Pickling cukes are usually shorter (6 inches or 15 cm) and "blockier" than slicing cucumbers, and have a bumpy or spiny skin. They're also crunchier, which is why they're best for pickling.
Gherkins are actually the fruits of the 'West Indian Gherkin' (Cucumis anguria), a close relative of the cucumber, which produces 1-3 inch long (25-76 mm) spiny fruits. Gherkins are grown just like cucumbers. Many pickles called "gherkins", however, are made from regular pickling varieties.
Round, yellow "lemon cucumbers" are about the size of a tennis ball. Lemon cucumbers are sweet and don't contain as much of the chemical that can make some cucumbers bitter. They also make colourful pickles.
English hothouse (also called Dutch or European) cucumbers have a ridged or smooth skin, virtually no seeds, and do not require peeling. As the name implies, they are usually grown in greenhouses.
Japanese cucumbers are long, slender, thin-skinned, and virtually seedless, and are often used in sushi or pickles.
Armenian cucumbers (Cucumis melo) are long and light green with thin, ridged skins that also don't need peeling. Asian cucumbers come in a wide variety of lengths, colours, and flavours.

Starting Cucumbers Indoors

To get a jump start on the season, start seeds indoors. This is important, as the outdoor season here can often be too short for cucumbers to thrive.

Cucumbers need a lot of warmth: ideally you will need a propagator or a warm south-facing windowsill. The reason early sowings can be difficult is that cucumbers grow very fast and will quickly outgrow the propagator. We reckon early April is the sweet spot; any earlier and their growth will be somewhat stifled once they germinate.

Sow 2 to 3 seeds about 1.5 cm deep in small (9cm) pots.
Keep at 20 degrees C in the propagator until the seedlings emerge.
The seeds should germinate in 3 -5 days.
The temperature after germination should be kept at a minimum of 16 degrees C.
Some will advise to plant cucumber seeds on their edge because if they go in on their flat they may rot. I'm not so sure about this but as cucumber seeds are expensive you might want to play it safe!
Thin to the strongest plant before translanting outside (see below).

Cucumber Seedling Care

When growing seedlings indoors you need to be careful that they don't get leggy, i.e. long spindly plants.

Seedlings become 'leggy' when they get too much heat and not enough light. If you are starting them off on a windowsill make sure they get as much daylight as possible. You can create a makeshift 'light box' by placing a sheet of reflective tinfoil on the room side of the seedling tray. This will reflect daylight onto the darker side of the plant.

If the plants are on a heat bench or in a propagator and they are looking spindly, turn the heat down and try to give them as much light as possible.

If 2 cucumber seedlings have germinated in any of your pots you need to remove the weaker one. Don't pull the seedling out, as you'll damage the roots of the one you want to keep. Instead nip the unlucky one with your fingernail or cut with a scissors.

Hardening off Cucumbers

Cucumbers raised in a propagator will need to be hardened off, even if you are still planting them indoors. A sudden temperature drop from the propagator to the temperature of the tunnel can kill the plants so you need to be careful.

If the spring is mild and the tunnel is warm enough, it will be fine to leave the plants out in the tunnel during the day and covering with a layer of fleece at night. If nights are still cold however return the plants to the propagator before darkness falls.

Remember to keep the compost moist but not soaking. Once the plants are planted into the larger bed in a week or so this will no longer be a problem.

Be careful transplanting, as cucumbers do not like their roots disturbed. Growing in biodegradable pots and transplanting pot and all can solve this problem.

Planting Cucumbers in Hills

A common way to grow cucumbers outdoors is in hills. This method ensures warmer soil and good drainage.

Dig a hole 18 inches (46 cm) wide and a foot (30 cm) deep.
Add compost to create a mix of half soil/half compost, and fill the hole with this mixture, creating a six-inch-high (15 cm) mound.
Plant five to six seeds per hill, one inch (25 mm) deep in a ring on top of the hill.
When the seedlings are about three weeks old, thin them to the two or three strongest plants per hill.
Snip off rather than pull out the unwanted plants, so as not to disturb the roots of the remaining plants.
Allow 18 inches (46 cm) between hills for bush varieties and 36 inches (91 cm) for trailing varieties.

Training Cucumbers on Supports

Cucumber plants can be either a) vining varieties with long vines or b) bush varieties with shorter vines. Vining cucumber plants will need a framework to grow up; otherwise they will trail along the ground. Growing vertically can save space as well as increasing yields.

To grow cucumbers vertically on a trellis, fence, or stake, the support should be 4-6 foot tall.
For trellising, sow seeds at the base of the trellis, one inch (25 mm) deep, three inches (8 cm) apart.
Thin to one foot (30 cm) apart.
To grow on a stake, train a primary runner to the stake and tie at 12-14 inch (30-36 cm) intervals like a tomato plant.
Cucumbers can also be trained to grow on a wire mesh arch.

If you have a tunnel it's handy to push a stick or bamboo in beside the plant and run a string from the stick to the crop bars or hoops on the tunnel.
Simply twirl the growing vine around the string as it grows.
You can use a tie every now and then to stop the vine sliding down the string.
I like to make a bamboo wigwam to support the vines. Once they out grow the wigwam they can be trained further up the tunnel structure.

Cucumbers can be planted in large pots (25cm would be a minimum) or in growbags.

Making a Cucumber Hotbed

This method depends on whether you can get your hands on a supply of new or fresh manure.

Place a generous pile of compost on top of some fresh strawy manure; the pile will need to be about a metre in diameter per plant.
A small timber raised bed would be ideal for this purpose.
Let the manure cool for a couple of days until the first burst of heat has subsided.
The pile will depend on how many cucumbers you're planting, but the distance is 45cm between plants to give you an idea.
Plant your cucumbers into the compost at a distance of 45cm apart.
The trick here is that the strawy manure keeps the roots of the cucumber warm and well-drained, helping to avoid problems with root rot.
If the night gets cold after planting out, you can drape some fleece over the plants: the heat from the manure will keep them cosy.

If you can't get your hands on the manure you can still grow a good crop of cucumbers, unless you're unlucky with very cold nights after you plant.

Make a pile of mound of compost and soil where you want to plant your cucumber.
Mix a good quantity of seaweed / manure pellets through the soil.
Plant in the top of the mound at a distance of 45cm apart.
The mound will aid drainage and help keep the roots from getting waterlogged.
If you do get cold nights after planting, place a layer of fleece over the young plants.

Watering Cucumber Plants

Cucumbers contain about 90% water, so it's no surprise that they need plenty of watering. However this is a bit of a balancing act, as cucumbers need the soil to be kept thoroughly moist but never water logged. This is a good reason for growing in raised beds or using a mound system (see above).

Keep a close eye on your plants and never let them dry out. The more moisture your cucumbers absorb, the sweeter they'll be.
Cucumber's roots can rot if left in a pot of soggy compost, so you need to be careful not to overwater when growing in containers. If in doubt leave them a little on the dry side. Be careful not to let the compost plug completely dry out or it will form a crust on top and won't absorb the moisture the next time you water.
It will all depend on the weather of course: on a hot day you will need to water twice a day; if it's dull every 2 days will be fine.

Cucumber Troubleshooting

If the plants are a little on the dry side you can get powdery mildew (a white powdery coating) on the leaves. You can combat this by using a diluted milk spray: mix 10% milk with water, and spray using a pump-action hand sprayer.

Be careful with root rot (already mentioned). The soil must be kept moist but not waterlogged. Earthing up plants with compost around the stem to produce new roots will help.

Male Flowers & Mature Fruits

Unless you chose an all female variety (recommended) you will need to remove the male flowers regularly, or else the fruits will have a bitter taste. Nip the flower out just below the flower head: this prevents the male flower from pollinating the female.

Don't let mature fruits stay on the vine: the cucumber will think it has done its job (namely producing seeds) and cease production of new fruit.

Feeding Cucumbers

Once the fruits start to swell you can feed the cucumbers by sprinkling some seaweed or poultry manure pellets in a wide spread around the base of the plant.

It is also a good idea to apply garden compost around the base of the stem. New roots will grow into the compost from the stem. This will also combat the problem of root rot, as a new batch of healthy roots are produced.

Harvesting Cucumbers

Cut your cucumbers from the vine; don't pull them off or you'll damage the vine. Each vine can produce between 20 and 50 fruits in a season. You'll get some odd shapes but they will all taste as good!

As already mentioned, make sure you harvest the mature fruit from the vine (even when you don't want it) because the plant will stop producing if you don't.