Growing Cucumber Outdoors

The term “cool as a cucumber” actually comes from the cucumber’s ability to cool the temperature of the blood. It can also kill the bacteria that are responsible for causing bad breath.

Best Cucumber Varieties to Grow in the Garden

There are two types of cucumber that you will see: picklers (stubby & bumpy) and slicers (long & smooth). Here is a list of the top 4 most popular cucumber varieties:

Growing Cucumber: Best Setup for Cucumber Plants

When growing cucumber, you’ll need:

Cucumber Planter:

Ceramic Self Watering Planter (preferred) or pot that is at least 12″ / 5 gal.

Soil:

Standard Potting Mix

Plant Food:

Herb Blend. This should be high in nitrogen (with NPK numbers like 10-5-5).

Grow Light:

A strong grow light that can give the equivalent of 7+ hours of direct sun [DLI of 21+ mol/m²/day].

Preparing your Cucumber Planter & Watering Schedule for It

Cucumber plants do well in moist soil conditions. If the soil dries out completely, the roots will die back, and it will be tough for the plant to recover. On the other hand, if the roots are exposed to standing water for too long, they can rot.

A Ceramic Self Watering Planter filled with a standard potting mix self-regulates to keep the soil at consistent moisture for your plant to thrive (and no watering guesswork for you).

To set one up:

1. Fill up the planter with dry soil from the bag, gently tamping down the top.
2. Dump the soil into a large mixing bowl and add water until the soil is moist, but not sopping wet (about ½ Cup)
3. Mix in 1 tablespoon of the Herb Blend Plant Food.

If you are using a regular pot instead, it should be a little bit bigger (at least 12″ / 5 gal) and will need drainage holes to prevent it from being overwatered. Let the top of the soil dry out between watering.

Starting Growing Cucumber: Seed vs Propagate

Cucumber plants are best to start from seed in the area they will grow to their full size (known as “direct sowing”). They’re not practical to propagate from cuttings & they don’t handle transplanting well. Fortunately, starting from seed is simple and they sprout quickly!

How to Plant Cucumber seeds and Seedlings

Cucumber grows quickly from seed. Plant 2 sites in a 12″ / 5 gal container. In larger containers, space sites 8″ apart. For each site, plant 2 seeds 1″ deep. Keep the soil warm (60-90°F, ideally 80°F). Sprouts typically appear in 7 days but can be as quick as 3 days or as long as 10 days depending on your conditions. To speed things up, you can soak them in water for 12-24 hours before planting.

Why starting Cucumber from Stem doesn’t make sense

Cucumbers are short-lived plants and prone to root rot. Even under perfect conditions, they lack the genetic makeup to readily produce roots from their stems.

Growing Cucumber: Where to grow your Cucumber plants

Cucumber plants have the highest light needs of any plant – so unless you have a totally unobstructed southern-facing window and plan on only growing in the summer – you’ll need a grow light. We still recommend taking advantage of your bright window (sunlight is free and great for plants!) and supplement it with a grow light.

For an introduction to grow lights, head over to our post on grow lights for indoor gardeners. We’ve also got a buying guide for screw in types, but to keep things simple in this guide, we’ll just provide directions for the 24W Screw in Bulb by Sansi.

How bright should your grow light be?

Cucumber plants need the equivalent of 7+ hours of direct sunlight [DLI of 21+ mol/m²/day] to grow their best. In order to provide an equivalent amount with a grow light, it needs to be pretty bright! The 24W Sansi bulb should be placed 6 inches away from the top of the plant. This will give your PPFD (the standard measure of brightness) of 500 μmol/m²/s.

How many hours per day do your Cucumber plants need under a grow light?

Cucumber plants are “day-neutral” and can grow under a range of daylight lengths. To ensure they get enough light, we recommend setting up a timer to keep your grow light on for 14+ hours per day.

Cucumber Plants Grow Faster in Warmer Temps

Cucumber plants are warm-weather crops that prefer temperatures around 80°F. They can grow well in conditions between 70 and 85°F but may lose their fruit if temperatures drop below 40°F. If it's too hot, they will drop their blossoms, wilt, and stop ripening. Most homes are in a good range, and a south-facing sunny window can provide extra heat if needed.

Week 1-2: Check for Cucumber Sprouts

Seedlings can appear as quickly as 3 days (though 7 days is more typical). If it’s been 10 days without any sprouts, your setup might be too cold.

Week 3: Thin Your Cucumber Seedlings

Thin your planter to only have 1 seedling per site, leaving the largest plant. If you are using the recommended planter (at least 12″ / 5 gal), this will mean you’ve got 2 plants after thinning. By removing the smaller seedlings, you’re allowing the biggest and strongest one to flourish by reducing competition for water, food, and space. If your seedlings are under 2 inches, stretching out, or folding over, they may not have enough light.

Month 1: How to Prune & Grow Cucumber on Trellis

Cucumber plants are vines that will continue to grow, so regular pruning is essential. Start trimming around the second month, or when you have 5 branches. Cut (or pinch) off the main stem above the 5th branch to encourage the plant to focus its energy on these branches. Consider training these branches up a fan trellis using plant clips for better support.

Month 2+: How to Pollinate Your Cucumber Flowers

We recommend using self-pollinating cucumber varieties because manual pollination can be cumbersome. Once flowers open, give them a gentle shake or lightly "rub the nose" of the flower to aid in pollination.

Month 3+: How to Harvest Cucumbers

Pick cucumbers often and thoroughly. They are at peak crispness for a short time, so frequent harvesting is key to enjoying their best flavor. Missing even one cucumber can cause the plant to end its lifecycle early, so stay diligent!

Month 12+: End of Life

Cucumber plants can last up to a year, but they will eventually become less productive. Once you notice a significant drop in yield despite adequate care, it’s time to start fresh with new seeds.

Shop This Blog

The right supplies can make caring for your plants much easier and turn maintenance from a daily chore into a weekly one. Here are some products we recommend for growing cucumbers successfully:

Best Containers for Cucumber: Ceramic Self Watering Planters

Plants thrive on consistent moisture but can suffer if they’re waterlogged. A semi-porous ceramic self-regulates ideal conditions. Our favorite is the COSWIP planter. A good alternative is the XS Self Watering Planter by Wet Pot.

Best Soil for Cucumber: Standard Potting Mix

Cucumbers prefer a rich, moist root zone, so a standard potting mix works best. We like the Potting Mix by Rosy Soil.

Best Nutrients for Cucumber: Herb Blend

Opt for nutrients that are high in nitrogen (with NPK numbers like 10-5-5). For a good herb blend, we recommend Joyful Dirt All Purpose.

Best Light for Cucumber: DIY or Soltech

If you lack bright windows, consider a grow light. For a higher-end option, we love the Aspect Light by Soltech. For a more budget-friendly setup, a DIY solution with a 24W Screw-in Bulb by Sansi, Clamp Light, and Mechanical Timer works well. Check out our complete guide on a DIY setup for less than $40 or our buying guide for screw-in bulbs.