How to Grow Cucumbers from Seed

It's easy to grow crisp, fresh cucumbers from seed at home! This guide walks you through all the steps for a bountiful harvest this season.

There's nothing better than biting into a juicy, homegrown cucumber on a warm summer day! Growing your own cucumbers from seed is really easy, and you can enjoy the fruits of your labor in less than two months.

Cucumber plants love warm weather and lots of water. Many like to climb on a trellis, making them easier to harvest and less susceptible to pests and disease.

So, grab your gardening gloves and let's start growing cucumbers from seed!

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Cucumber Cultivars

There are two types of cucumbers: bush and vining. Bush varieties are smaller plants and perfect for containers. Vining types usually produce more fruit over a longer time, but providing a trellis is crucial.

Here are a few of the most popular cucumber varieties and their days to harvest. 

• ‘Marketmore’: Vining, 68 to 76 days
• ‘Straight Eight’: Vining, 58 days
• ‘Burpless Hybrid’: Vining, 62 days
• ‘Fanfare’: Bush, 63 days
• ‘Bush Pickle’: 48 days

This year, I'm growing Sashimi cucumbers from seed. This variety is a seedless hybrid that does not need pollination to grow fruit.

Growing Cucumbers from Seed Indoors

Starting cucumbers indoors will give you a head start on the growing season. This gives you more control over temperature conditions, pests, and fertilizing so you can plant the most vigorous seedlings in the garden. Transplanted seedlings generally mature about two weeks before direct sown plants. 

Start seeds indoors two to three weeks before you want to transplant them outside. Remember that cucumbers like it hot, so wait until daytime temperatures are consistently in the range of 70°F, after all danger of frost.

To grow cucumbers from seed indoors:

• Sow the seeds in small peat pots or large cell trays in a seed starting mix. 
• Plant one or two seeds per cell, ½ to 1 inch deep, and firm down the soil. 
• Water thoroughly after planting and keep at a soil temperature between 65 and 85°F. 
• Give the seedlings bright light as soon as they emerge to prevent them from getting leggy. 

Cucumber seedlings germinate quickly, typically in 5 to 10 days. Transplant outside when you see three sets of true leaves, being careful not to disturb the roots while handling.

Direct Sowing Cucumber Seeds

Direct sow cucumber seeds when the daytime soil temperature reaches 65°F. Use a soil thermometer to test the temperature before planting. Cucumbers are highly frost-sensitive, and even a light freeze can damage them.

When sowing cucumber seeds directly into the garden, make small hills about a foot in diameter and 4 to 5 feet apart, planting about five seeds per mound. Thin the plants to a 1-foot spacing after germinating, or grow 3 or 4 plants close together with about 18 inches between groups.

But you don't have to plant directly in the ground! I'm growing cucumbers in grow bags this year, with a string trellis to guide them upward. This one took off like a rocket and grew over two feet in just a couple of weeks, and is already fruiting!

Transplanting Cucumber Seedlings

Cucumbers benefit from rich, fertile, well-draining soil and lots of water. In hot weather, plan to water at least once per day. In extreme heat, the plants might need water in the morning and evening, especially when fruiting. I have my cucumber plants set up on a drip irrigation system that automatically waters them every morning.

If the soil is low in nutrients, mix plenty of high-quality compost or 5-10-10 fertilizer into the soil before planting. Give the plants another dose of nitrogen fertilizer after flowers appear and then three weeks later. However, be careful not to over-fertilize, or you'll get more foliage and less fruit.

Cucumbers grow well with straw or mulch (plastic or organic) over the soil to heat the roots and retain moisture. Another benefit is a reduction in weeds around the plants. Wait until the soil temperature gets to 75°F before applying organic mulch, or it can keep the soil too cool.

If you grow cucumbers under a cover to keep them warm, remove it when the flowers appear to allow insect pollination. Also, cucumbers dislike being under cover when temperatures get above 90°F. 

Cucumber plants typically produce between 7 and 10 pounds of fruit for every 10-foot row over eight to ten weeks. They mature quickly and can get over-ripe if you don’t pick them regularly. Harvesting triggers the plant to go on flowering and making more fruit for a longer time.

Caring for Cucumber Plants

Cucumbers are bothered by a variety of pests and diseases. Most of these are easy to control if you choose cultivars to match your location, plant them in full sun with good soil drainage, and provide lots of water.

Monitor the plants for pests and remove them as soon as possible. The most common issues are cucumber beetles, powdery mildew, and aphids. Cucumber beetles can cause the plants to succumb to bacterial wilt and die when the flowers first appear.

Start harvesting fruits 5 to 7 days after the flower opens and when the fruits are bright green. Regular water during harvest is essential to prevent the fruits from getting bitter.  

Break or cut the stem about ½ inch above the top of the fruit when picking, and immediately store cucumbers in the refrigerator away from apples to keep them fresh.

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Now that you know how to grow cucumbers from seed, you can enjoy your harvest all summer long! Whether you slice them up for salad, store them in vinegar for pickles, or eat them straight off the vine, they're one of the best summer vegetables that are super easy to grow yourself!