Growing Cucumbers in a Greenhouse

Cucumbers are a much more diverse crop than most people realise: supermarkets have given most people the impression that the waxless English cucumber and the gherkin are the only two options available, but most gardeners know better.

Lesser-known selections have diverse flavours and textures. The sweet, round, yellow Lemon cucumber is great for making cucumber water and for fresh eating. Slightly bitter, thick-skinned German Schälgurken are perfect for frying. Round Dosakai cucumbers, hailing from India, are great for making chutney.

Choosing Your Cucumbers

Cucumbers can be a complicated crop to grow perfectly, so choosing the right cultivar for greenhouse growth is crucial.

Climate: Outdoor or Greenhouse?

Some cultivars of cucumber can be grown outdoors, so while they can be started in the greenhouse, they are best moved out into the garden once temperatures allow for it. Cucumber plants take up a lot of space, so only the ones that need to be in the hothouse for the whole season should remain there.

Shape: Bush or Vine?

Bush cucumbers have very short vines on which they bear their fruits, as they have been bred to take up a minimal amount of space. Generally, they will require about 1 m2 of space.

Vine cucumbers require a trellis or support, as they will attach and grow vertically if given the chance. Alternatively, they can be left to grow along the soil, but using vertical space gives a much better economy of limited greenhouse real estate.

Pedigree: Heirloom or Hybrid?

Heirloom cukes can offer some really interesting colours and flavours. Cultivars like Crystal Apple White Spine and Boothby’s Blonde have unique characteristics that aren’t necessarily matched in newer hybrids.

Hybrids do, however, usually have the advantage of being easier to crop as well as heavier cropping, and more disease-resistant.

Thus the choice is mostly a matter of personal preference. Why not try both?

Purpose: Slicing, Pickling, or Burpless?

Slicing cucumbers are for fresh eating, and are generally long, smooth fruits that are picked early, while they are still sweet.

Picking cucumbers--"gherkins" or "wallies" in the vernacular--are pretty self-explanatory: they are the best selections for long-term preservation. Most sliced cucumbers can also be pickled mind you, but the best picklers have been bred for uniformity in length and diameter, as well as a consistent, void-free interior flesh. They also never have waxed skin.

So-called “burpless” cucumbers are grown for their thin skin and lack of seeds, which are purported to give some people gas. They can be used for either slicing or pickling.

Planting and Care

Sowing

Cucumber seeds should be sown roughly three weeks before they are to be transplanted, so calculate according to where they will be planted and temperature predictions for the season. The germinate best at a soil temperature of between 21 to 29 ?C.

Transplanting

Most squash-type plants don’t particularly like being transplanted, so moving the plant from the cell or pot in which it germinated to its permanent home for the season is advisable.

Fruiting

Cucumber pollination is slightly complicated, and depends heavily on which type of plants have been selected.

Parthenocarpic or seedless fruits--like “burpless” cukes--are usually grown inside a greenhouse that excludes bees, in order to keep them from being pollinated.

Some cucumber plants that require pollination, on the other hand, have male flowers and female flowers that bloom at different times, or are “self-incompatible.” They require a pollination partner of another cultivar.

Newer hybrid cultivars produce mostly female flowers, which means they bear more fruit, provided adequate pollination.

Pests and Diseases

The greatest insect threats to cucumbers--and most squash-type plants--are stem borers and certain beetles. Good hygiene and careful inspection of plants can help stop problems before they begin.