When Should You Start Cucumber Seeds Indoors?

when should you start cucumber seeds indoors

April is the best time to start cucumber seeds indoors. This gives the warm weather plant enough time to soak up the spring and summer sun. They can then be transferred to a (raised) garden bed in mid-May or kept in planter in a sunny spot.

Cucumbers do very poorly in cold conditions but thrive under the sun. This makes them a great vegetable to grow indoors in a room with big windows. They can also be grown outdoors but wait for late spring or early summer to do so.

Want to learn more about how to grow cucumbers at home? This is what you need to know about the best time to start cucumbers indoors.

When Should I Start Cucumber Seeds When Growing Indoors?

There are two parts to this question; whether cucumbers grown from seeds should be started indoors and if so, when the best time would be to do so. Let’s address both.

Should You Start Cucumbers Indoors?

It is best to start cucumbers indoors if you live somewhere with big changes between the seasons.

In other words, if you can say that you get a clear winter, spring, summer and fall, your cucumber seeds have a better chance of succeeding when started inside.

This is because the roots of cucumbers are quite slow to grow. They are very fragile during the first weeks of their growth cycle and not resilient enough to acclimatise to unpredictable cooler weather.

Even the slightest chance of frost is a good enough reason to grow cucumbers indoors. Once they have developed into sturdier seedlings, they can be transplanted to your garden or an outdoor planting pot.

growing cucumbers indoors

What Month Should You Plant Cucumbers?

When growing cucumbers from seeds, start them indoors at the beginning of April.

The first few days of April, or even towards the end of March, are a good time to start growing cucumbers indoors. This gives the seeds plenty of time to germinate before outdoor planting season starts.

By the time they are big enough to move outdoors, it will be at least May. For most countries in the western hemisphere this is well into spring and nearing summer. This means there is practically no more risk of frost and the soil has warmed up significantly.

If you want to start cucumbers outdoors, you can wait until the end of May or the beginning of June. This gives you the best odds for consistently warm weather.

How Do You Start a Cucumber Indoors?

We have a complete article outlining how to plant cucumbers seeds so this is just a quick summary. This is also the best way for how to grow cucumbers in an apartment.

  1. Fill the starter container with seed starter mix
  2. Poke holes of 1/4 inch, spaced 1/2 inch apart
  3. Place 1 cucumber seed in each hole
  4. Fill each hole with more seed starter mix
  5. Gently press down the soil, adding more soil if it forms a sink
  6. Water the soil without it becoming soggy
  7. Press down the soil to make it more compact but still keeping it airy
  8. Place the container in a spot with full bright sunlight
  9. Check daily to make sure the soil constantly stays moist

How Long Do Cucumber Seeds Take to Germinate?

In ideal conditions, cucumber seeds can germinate within 3-14 days. 

When starting the seeds indoors, it is very important that they receive lots of sunlight. Window sills are often best, as are very bright rooms.

All the sunlight and warmth that they get does put the soil at risk of drying out. That is why the soil of cucumber seeds should be monitored daily.

Water daily if necessary but don’t let the container stay flooded, either. If the soil gets too soggy the roots might rot.

Can Cucumbers Be Grown Indoors Completely?

If you are worried about the weather being too cold for your cucumbers, you can grow them inside, from start to finish. However, these are vegetables that need quite some space to grow so consider whether your home is large enough.

Depending on the specific cucumber variety, you will need a plant container that can hold at least 5 gallons of soil. It doesn’t have to be too deep, around 10 inches is best.

Look up the specific requirements of indoor cucumber species. Below is a list of cucumbers that are best grown indoors.

Indoor Cucumber Varieties

These cucumbers grow well in a container.

  • Bush Champion
  • Corinto
  • Fanfare
  • Pot Luck
  • Salad Bush
  • Tyria
  • Unistars

Frequently Asked Questions:

Still have more questions about starting cucumber seeds and growing them indoors? Let’s do a quickfire round.

Can you plant cucumber seeds from a cucumber?

Sorry, this is highly unlikely. The cucumbers we buy in stores are often harvested too early for the seeds to mature. Many of today’s varieties are also modified to have non-germinating seeds.

Can you grow cucumber in winter?

Cucumbers are very sensitive to cold so they cannot be grown outdoors in winter. However, you might be able to grow them indoors if the room temperature is consistently warm and placed in a spot with lots of direct sunlight.

How long does it take to grow a cucumber indoors?

It takes about 2 months for cucumbers grown indoors to reach maturity. This is in addition to the seed germination time of 3-14 days.


Cucumbers grow best in the spring and summer. If you are growing cucumbers from their seeds, you can start them indoors around April. Once germinated and grown into more resilient seedlings, they can be grown outdoors from mid-May onwards.

Alternatively, you can continue growing cucumbers indoors. Just make sure the container is large enough and receives enough sunlight. Exact soil and climate conditions depends on the indoor variety you are planting.

You need to wait approximately 2 months from the time the seeds are planted to the time the cucumbers are ready to eat. Start now and have you own homegrown cucumbers this summer.

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