I find cucumbers quite finicky to grow in the zone 3 gardening climate here in Calgary Alberta! If you have previously tried growing cucumbers and it has not gone well, know that you are not alone. Lets discuss some tips on growing cucumbers from seed in Alberta (including when to plant your cucumber seeds), transplanting cucumbers, watering your cucumber plants as well as other tricks to help you successfully grow cucumber plants in cool gardening climates.
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Cucumber Varieties to Grow in Your Garden
There are both vining and bush varieties of cucumbers. Bush cucumbers are good for containers or small gardens. Vining cucumbers grow well vertically up a trellis or, if you have space, they can sprawl out on your garden bed. Cucumbers are prone to disease when the leaves are wet so growing them vertically on a trellis or on a small mound can be beneficial to keeping the leaves up and out of pooled water.
Other cucumber varieties are slicing or pickling cucumbers. Slicing cucumber varieties grow to be 6 to 12 inches long where pickling cucumbers are 3 to 4 inches in length.
Preparing Soil for Cucumbers
Cucumbers grow best in a full sun location in well drained soil with plenty of compost. High nutrient levels in the soil will promote quick growth in your cucumbers during our short zone 3 growing season. Use a fertilizer high in potassium, as potassium is what encourages blossoming and fruit production in plants. Another option is making a high potassium "fertilizer tea" by adding a banana peel to a quart of water and letting it sit in a cool place for 3 days then using this "tea" to water your cucumber plants.
How to Grow Cucumbers from Seed
Plant cucumber seeds 1 inch deep and around 6 to 12 inches apart. Cucumber seeds require soil temperatures of at least 20°C to germinate. These warm soil temperatures can be difficult to achieve in zone 3 Alberta gardens, making cucumber seeds difficult to germinate in outdoor vegetable gardens.
You will get more consistent germination when starting cucumber seeds indoors. When planting cucumber seeds indoors, seed them 3 to 4 weeks prior to your desired transplant date. I recommend using peat pots to start your cucumbers in as they do not like having their roots disturbed during transplanting and are prone to transplant shock. Check out When to Start Seeds Indoors to find a printable growing chart for starting seeds indoors in zone 3 Alberta.
If you choose to direct seed your cucumbers, consider using a row cover or cloche to keep the soil warm. Uncover the cucumber plants as soon as you begin to see blossoms to allow pollinators access to the blossoms.
Many of us have had our cucumbers wilt and die shortly after transplanting. Did I mention cucumbers can be finicky? Cucumber transplant shock can happen from change in temperature or having their roots disturbed.
The best time to transplant your cucumber plant is once it has developed its true 3rd leaf. (Don't count the first two leaves out of the ground. These leaves will look different than the succeeding leaves and can be snipped off once the 3rd true leaf is developed.) At this stage the plant is strong enough to withstand the change in environment and at the same time not so large as to have devolved to a stage where you will have to disturb it much during transplanting.
To prevent cucumber temperature shock take at least a week to harden off your cucumbers. (See "How to Harden off your Plants in a Week".)
Cucumber plants do not like temperatures of less than 5°C at any time. Plan to wait to transplant until night temperatures are consistently 5°C or above. For me, near Calgary Alberta, this means waiting until the middle of June until my cucumbers go outside. Other options are using a greenhouse, cold frame or covering to insulate the plants from the cool night air.
To protect cucumber plants roots during transplant gently tear or cut the bottom of the peat pot off, leaving the sides intact and plant it like this. Form a small mound around the stem to keep it from sitting in water.
Always water any type of plant in as soon as possible after transplanting to help the soil settle around the plant and to prevent further shock.
Cucumbers love consistent water in well drained soil. Avoid getting the plant leaves wet when watering. If your plants are on a sprinkler system, watering in the morning vs. the evening allows the leaves to dry off sooner. Mulch will benefit your cucumbers by retaining moisture for longer periods and keeping the cucumber leaves out of pooled water. Avoid over watering cucumber plants.
Encouraging Cucumber Production
Most cucumber plants have both male and female blossoms. The female is the one with the mini looking cucumber at the base of the blossom and is the one that produces cucumbers. The purpose of the male blossom is to pollinate the female but it is not fruit bearing. If you want to be sure your blossoms get pollinated you can do this yourself by using a Q-tip or paint brush and gently brushing it over and around the male blossom and then the female blossoms.
Cucumbers will produce more when picked often. Because they grow so quickly, try to pick cucumbers every second day.
Cucumber Pests and Disease
Pests and disease that commonly attack cucumber plants include aphids, cutworms, thrips, cucumber beetle and powdery mildew. If your established cucumber plant begins to show singes of wilt even when watered check for these pests.
Cucumber Companion Plants
Planting marigolds, dill and/or cilantro next to your cucumbers will discourage pests. Nasturtiums attract aphids but can withstand their attack. Planting nasturtiums near your cucumbers can keep the aphids off your more sensitive cucumber plants.
Avoid planting cucumbers near potatoes or sage.
Print of my free companion planting chart for reference when planning your garden.