Here is the BEST Time to Start Sunflower Seeds in New Hampshire (2023 Guide)

Do you want to grow sunflower seeds in New Hampshire, but don’t know when to start them?

Starting sunflower seeds is not as easy as it seems.

Here’s why:

  • Sunflower Seeds must be consistently watered, receive at least 8 hours of sunlight a day, & be kept at room temperature of at least 70 degrees Fahrenheit.

So if you don’t consistently water them they won’t germinate. If they aren’t in a room that is at least 70 degrees Fahrenheit they won’t sprout. And if it receives 8 hours of sunlight the plant itself won’t grow.

  • Because New Hampshire’s growing season is not long enough, sunflower seeds cannot be sowed outside and should only be started indoors.

Because of this, I’m going to teach you the ideal time to start sunflower seeds indoors in New Hampshire:

  • To Learn More About HOW to Grow Sunflower, Check Out This GUIDE!

When to Start Sunflower Seeds Indoors

Depending on the type of sunflower, it takes roughly 10 to 14 days to grow sunflower from seed indoors before you can transplant them into your garden. And it could take 12 to 18 weeks for your sunflower to bloom!

The approximate date of when you should start your sunflower seeds indoors can be found by:

  • Finding the last average frost date HERE
  • And then subtract 10 days from it

You can also find the average last frost date for most major cities in the below chart that I have created:

new hampshire frost dates

To help ensure the greatest success of your sunflower seeds germinating you should:

  • Use a heat mat to ensure the gardening pot remains at 70 degrees Fahrenheit
  • Use a grow light to control how much light your sunflower seeds receive
  • Water your seeds with a spray bottle to ensure your seeds are not overwatered

It should also be noted that you will not want to introduce your sunflower plants into your garden until 2 weeks after your last frost or else your plant will potentially die or not bloom

If you want to learn WHEN to start ANY Flower Seed in New Hampshire, head over to HERE and just type in the flower you want to grow.

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