Soil
These plants tend to like loamy soils. Dark in color, it has a lot of organic material and feels as moist as a rung-out sponge. If you compost, or know where to get very good quality compost, fantastic. Use pure compost in my opinion. Or, plant in the ground and mix compost into your native soil. 
Compost is rich soil created from the breaking down of leaves and food scraps by either bacteria or critters like worms. Pre-made potting soils will be made of inert and unsustainable material, usually peat moss, that features the correct drainage and texture needed for root stability. BUT it will have added non-organic fertilizer that completely drains out over time, requiring you to add more. Peat is unnecessary! You want your soil to be alive with microorganisms creating nitrogen, phosphorous, and potassium continuously. Compost has the right stuff for cucumbers, with the added benefit of providing the plant with just the right moisture throughout the day.
Hot tip: You can test drainage before planting by placing the soil into a small flower pot. Pour water over it, and if the soil uniformly moistens and drains easily, you’ve found what you need.
Soil and Heat
The greater the soil volume, the better your cucumber plant will fare, and the more cucumbers you will get. Soil volume correlates directly with crop output. Planting in the ground will protect your plant’s roots from heat, allowing the roots to grow deeper, and to seek out water wherever it is. If you must plant in containers, here are a few helpful tips.
When deciding on a location, take into consideration the amount of heat your area gets during the day. The sun will heat up the soil and dry it out faster, not to mention bake the cucumber’s roots. Water more often, and try to shade the container – but only the container. This will regulate the temperature of the roots, causing less stress and giving a healthier cucumber plant.
In Tucson, we get temperatures upwards of 110F (43C) so shade is required. In cases like this, take as much advantage of the morning sun as possible. It is cooler and will still give the right amount of light throughout the day. See Protecting Cucumber From Heat Stress for more info.
Soil Depth
The deeper the soil, the better the cucumber plant health. But remember, you can grow cucumber successfully in containers with the right care, placement, and soil mixture. If planting in the ground, amend the soil to a depth of 1.5 to 2 feet. If you are growing in a container, at least 3 cubic feet of soil is a must, and ideally, the container will be equal in size on all sides. Wide and flat or tall and skinny are not practical for heat tolerance or water retention.
Excited to start? Check out how to grow cucumbers for more.
