Growing cucumbers from seed is fast and easy. They germinate very quickly, and you can either start them indoors or plant them directly into your garden.
In this post, I’ll show you everything you need to know. Even if you’ve struggled with it in the past, you’re sure to be successful after reading my complete guide.
Here you’ll learn all about how to grow cucumber seeds. Including when and where to sow them, the best method to use, exactly how to plant them step by step, how long it takes them to germinate, seedling care tips, and much more.
Growing Cucumbers From Seed
| Days to germination: | 3-10 days |
| When to start indoors: | 4-6 weeks before transplanting |
| When to sow outside: | 1-2 weeks after your last spring frost date |
| Days to maturity: | 50-70 days |
| Sun exposure: | Full sun to partial shade |
| Seed planting depth: | 1” deep |
| Plant spacing: | 12-18″ apart |
| Soil temperature: | 60-80°F |
Types To Grow
There are tons of different types of cucumber seeds you could plant in your garden. The variety you choose depends on what you want to use them for, and your preferred flavor or texture.
A few of my favorites are Marketmore, Homemade Pickles, and Baby Persian. It’s also fun to grow an heirloom lemon variety for something different.
How Long From Seed To Harvest?
In general, the amount of time it takes from when you plant the seeds to when you can expect to start harvesting your cucumbers is between 50-70 days.
Some types are faster than others, so the exact length of time will depend on the variety you have. It also depends on your climate and the growing conditions.
Related Post: How To Grow Cucumbers
Tips For Planting Cucumber Seeds
Below I will give you all the details you need about exactly when and how to plant your cucumber seeds. But first it’s important to choose the best sowing method and prepare for planting.
Cucumber Seed Starting Methods
There are two methods you could use for planting your cucumber seeds: 1. direct sowing or 2. starting them indoors.
They don’t like to be transplanted, and they grow very fast. So I prefer planting them directly into my garden, which is usually the best way to do it. But you can use whichever technique works for you.
- Direct sowing (best method) – Sowing them directly into your garden is usually the best and easiest method to use. This way you don’t have to worry about caring for them indoors or transplanting them later on.
- Starting indoors – Use this method if you have a very short summer, or if your garden soil isn’t ideal for direct sowing. I recommend using either plantable pots or large pellets, which will help to minimize transplant shock.
Related Post: 3 Seed Starting Methods That Every Gardener Should Try
When To Start Cucumber Seeds
You can plant your cucumber seeds directly into your garden a week or two after your last spring frost date. The cold will stunt them, so wait until the ground warms to 60°F or higher. You can use a soil thermometer to check it.
If you want to start them indoors, then you’ll need to plan ahead. In that case, you should sow them 4-6 weeks before the average last spring frost date in your area.
Related Post: When To Start Seeds Indoors
Preparing Cucumber Seeds For Planting
There’s nothing special you need to do to prepare cucumber seeds for planting. You can simply sow them directly out of the packet.
However, soaking them in warm water for 12-24 hours beforehand will soften them up and can help them germinate faster.
Related Post: 13 Unique Cucumber Trellis Ideas
Cucumber Seed Germination Time
One of the reasons it’s so fun to grow cucumbers from seed is because they sprout very quickly. The germination time can be anywhere from 3-10 days.
They will germinate faster in warm soil. So if you want to speed it up, then use a heat mat indoors to keep them warm, or wait to plant them outside until the ground has reached at least 60°F.
What Do Cucumber Seedlings Look Like?
The first two leaves that open right after they germinate are oval and slightly pointy at the tips. Those are called the “seed leaves”.
All of the others that form after that are called “true leaves”, and they look like tiny cucumber leaves. As the true leaves grow larger, the seed leaves will eventually turn yellow and die back.
Related Post: Why Do Cucumbers Turn Yellow & How To Prevent It
How To Care For Cucumber Seedlings
If you planted your cucumber seeds right in the garden, then you can skip this entire section. But, if you started them indoors, here’s how to properly care for your seedlings:
Light
Once they pop out of the soil, cucumber seedlings grow very fast. So it’s important to use a grow light as soon as they germinate, otherwise they will quickly get tall and leggy. A sunny window won’t be bright enough.
Position the light so it hangs 3-4″ above the top of the leaves at all times. Use an outlet timer to make sure they get 14-16 hours of light every day.
Related Post: How To Use Grow Lights For Seedlings
Water
They also need consistent moisture, so never let the soil dry completely. It should always stay damp, but never wet or soggy. Use a moisture gauge and keep the reading between 4-6 to ensure you get it right.
Fertilizer
As soon as your cucumber seedlings get their first true leaves, feed them with a 1/2 dose of organic liquid fertilizer. They love fish emulsion or compost tea as well.
Potting Up
Pot up your cucumber seedlings as soon as they are twice as tall as the original container or seed tray. I recommend using plantable pots made out of peat moss, coco coir, or dried cow manure.
That way the roots won’t be disturbed when you move them into your garden, which will help to prevent transplant shock.
Related Post: How To Grow Cucumbers Vertically
Transplanting Cucumber Seedlings Into The Garden
If you started them indoors, then it’s crucial that you take the proper steps to transplant your cucumber seedlings into your garden to ensure they will thrive.
The first step is to harden them off to prepare them for the transition. Do not skip this, or they may not survive.
They hate the cold, so wait until all chance of frost is gone, and the soil is at least 60°F before planting them into your garden. Use a soil thermometer to check it.
FAQs
If your cucumber seeds won’t germinate, it’s likely that it was either too wet or too cold and they rotted. Wait to plant them until the soil has warmed to 60°F or more, and keep it evenly moist. Otherwise the seeds may not have been viable, so if you’re using older ones then plant 2-3 per hole.
No, cucumber seeds do not need light to germinate. However, the seedlings need 14-16 hours of light daily as soon as they begin to sprout, or they will quickly become leggy.
You can germinate your cucumber seeds faster by giving them plenty of warmth. Keep the soil between 60-80°F at all times. You could also try soaking them before you sow them, which can help to speed things up as well.
Planting and growing cucumbers from seed is simple and fast. No matter which variety you choose, you are sure to be successful if you follow the step by step instructions in this detailed guide.
If you’re tired of struggling, and want to learn how to grow any plant you want from seed, then enroll in my online Seed Starting Course. It’s a wonderful, fun, self-paced course that will teach you everything you need to know to easily grow your own seedlings. Enroll and get started today!
Or, if you just need a refresher, then my Starting Seeds Indoors eBook is for you! It’s a quick-start guide that will get you planting seeds in no time.
Share your tips for how to plant cucumber seeds in the comments section below.
Printable Step-By-Step Instructions
How To Plant Cucumber Seeds Step By Step
Follow these steps for planting cucumber seeds indoors or outside. The instructions are the same no matter which variety you choose to grow.
Materials
Instructions
- Prepare the soil or pellets - When planting outdoors, loosen up the top few inches of soil and remove any weeds. Indoors, pre-moisten the pellets or seed starting mix before filling your trays or pots.
- Decide how many seeds to plant - Indoors, plant one seed per hole or pot. In the garden, sow the seeds 12-18" apart.
- Plant your cucumber seeds - Lay them on top of the soil, and gently push them down about 1" deep. Or you can make the holes first, and then drop the seeds in.
- Cover the seeds - Fill the hole in with soil, then gently press it down to ensure it comes into contact with the seeds.
- Water them - Gently moisten the soil, taking care not to displace the seeds in the process. It should be damp but never soggy or saturated. Use a moisture gauge to get it just right.
- Cover the trays (optional) - Indoors, cover the seed trays with a plastic dome lid, and place them in a warm location. A heat mat will help them germinate faster.
Notes
Cucumber seedlings don't like to be transplanted, and doing so can stunt their growth. If you want to start them indoors, I recommend using plantable pots or large pellets rather than trays. The plantable pots will help to minimize transplant shock.
kimberly piazza says
Something ate the first two leaves on my cucumber plant will it still grow or should I just buy a bigger cucumber plant and plant it
Amy Andrychowicz says
Oh no, sorry to hear something ate the leaves on your cucumber seedlings. If all of the leaves were eaten, then the seedlings won’t grow anymore. If, however, there are tiny leaves forming in the middle of the seedlings, then there’s hope. In that case, I would leave them and see if they still grow. The good news is that there’s still time to plant more cucumber seeds!