Do you want to grow cosmos seeds in Iowa, but don’t know when to start them?
Starting cosmos seeds is not as easy as it seems.
- Cosmos 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 Iowa’s growing season is not long enough, cosmos 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 cosmos seeds indoors in Iowa:
- To Learn More About HOW to Grow Cosmos, Check Out This GUIDE!
When to Start Cosmos Seeds Indoors
Depending on the type of cosmos, it takes roughly 7 to 10 days to grow cosmos from seed indoors before you can transplant them into your garden. And it could take 3 months for your cosmos to bloom!
The approximate date of when you should start your cosmos seeds indoors can be found by:
- Finding the last average frost date HERE
- And then subtract 7 days from it
You can also find the average last frost date for most major cities in the below chart that I have created:
To help ensure the greatest success of your cosmos 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 cosmos 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 cosmos 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 Iowa, head over to HERE and just type in the flower you want to grow.