When I think of cucumbers, I think of the idiom “cool as a cucumber” , which may be based on the fact that even in hot weather, the insides of cucumbers remain cooler than the air.

Cucumbers, the second most popular greenhouse crop after tomatoes, certainly do not like cool weather. In fact, they thrive in hot humid greenhouse conditions combined with a very generous amount of water.

There is a dizzying assortment of cucumber seedling available at the various garden centres, however, cucumbers can be broken down into four categories.

Dark green slicing types of cucumbers, such as Marketmore and Fanfare, are early varieties and have been popular. They should be peeled before using because the chemicals that cause digestive gas are found just below a cucumbers skin. These types of cucumbers need to be pollinated.

Then there are the “burpless” varieties, so called because they lack the chemicals that cause gas so they are more easily digested. Varieties include English Telegraph (sometimes called English Long), Sweet Slice and Sweet Success. The Sweet Slice and Sweet Success cucumbers are identical to the normal slicing cucumbers, but the taste is very mild and sweet and they are self-pollinating.

Pickling cucumbers are shorter, thicker and lighter in color than slicing types and often will produce higher yields of smaller fruits, making them ideal for harvesting in larger batches and, of course, for pickling. Recent developments in pickling cucumbers are varieties that produce only female flowers, thereby resulting in earlier and more abundant fruit set.

Unusual varieties are also fun to grow. You might want to try “Lemon” is sweet-tasting heirloom cucumber with round, yellow, baseball-sized fruit.

Cucumbers like very warm, well drained soil.I recommend using plastic mulch on the soil to keep it at a temperature in the 18°–21°C range. Using plastic mulch with cucumbers is now standard practice for a lot of the commercial growers. Cucumbers, similar to tomatoes, respond well to a liberal amount of nutrients, and if you’re using organic fertilizers, 1 cup of complete organic fertilizer per plant is not too much (you can also use Miracle Grow or 20-20-20).

Once the fruit is pollinated, cucumbers take a tremendous amount of water. When you think about it the “cool” of cucumbers part is in part that they are made up of large portions of water. I remember looking at small cucumbers at the beginning of the week and wanting to take them to market by the weekend, we would literally try to drown the plants. In combination with hot July weather, you could practically watch them grow and within a week the cucumbers would be ready to go to market.

For all of the slicing cucumbers, and some pickling cucumbers, the flowers must be pollinated. This year, we seem to have more bees than what I have seen other years, but in greenhouses the bees may not always be present.

The English cucumbers as well as Sweet Slice and Sweet Success are self-pollinating, consequently you don’t have to worry about finding the male and female flowers.

In my own greenhouse, I found that the Sweet Slice and Sweet Success cucumber varieties did better than any of the other slicing types.

We had encountered some problem with bitter-tasting fruit, which we learned by trial and error could be caused by wide temperature fluctuations, cool soil, or using cold water, all of which contribute to the malfunction of one of the enzyme systems that prevent bitterness in cucumbers. Once we switched to Sweet Slice cucumbers, the bitterness problem was resolved.

Cucumber plants are indeterminate in growth, continually producing fruit on new growth, similar to greenhouse tomatoes. Greenhouse cucumbers are more sensitive to low temperatures than tomatoes. Ideally minimum temperatures should be no lower than 18°C for sustained production.

Keep cucumbers plants in your greenhouse warm, give them adequate moisture (especially once the fruit starts to develop) and sufficient nutrients, all summer long and you will be rewarded with cool cucumbers that are a delight to eat.