Here is the BEST Time to Plant Saint John’s Wort in Iowa (2023 Guide)

Do you want to grow saint john’s wort in Iowa, but don’t know when to plant them?

Planting saint john’s wort is not as easy as it seems.

Here’s why:

  • saint john’s wort are not able to survive frost or cold weather under 50 degrees Fahrenheit.

So if you plant them outside too early in the spring they will die. And if you plant them too late, your saint john’s wort won’t produce a bloom.

Today, I’m going to teach you the ideal time to plant saint john’s wort in Iowa:

  • To Learn More About HOW to Grow Saint John’s Wort, Check Out This GUIDE!

When to Plant Saint John’s Wort in Iowa

As you may have already guessed, you need to pay very close attention to your local weather in the spring. Specifically, you are going to need to watch when the last frost occurs.

In general, when there hasn’t been a frost for two weeks, you are SAFE to plant your saint john’s wort outside in Iowa!

For your reference, I have created this table for average frost dates for most major cities in Iowa. If your city is not listed below you can find its Last & First Frost Dates HERE.

Iowa Last & First Frost Dates

Iowa Frost DAtes

Unfortunately, Mother Nature plays cruel tricks on us every year.

It should be noted that the above dates are just averages.

There are years when the last frost comes MUCH later. Sometimes, the last frost happens much earlier and you can get your saint john’s wort planted outside in Iowa much quicker.

Like I said before, you need to be very diligent in checking your local weather.

So what happens if a frost comes AFTER you plant your saint john’s wort?

When you know a frost is coming you need to take action.

  • If saint john’s wort are in pots, bring them inside
  • If saint john’s wort are in the ground, cover them in burlap and hope they survive

Also, make sure not to plant your saint john’s wort in your garden too late.

  • Planting saint john’s wort too late will cause small blooms or even worse, no blooms.

When Should You Start Your Saint John’s Wort Seeds Indoors?

Depending on the type of saint john’s wort, it takes roughly 10 to 20 days to grow saint john’s wort from seed indoors and then transplant them to your garden. And then another 1 years to bloom!

For a specific date that you should start saint john’s wort seeds indoors you should:

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

Not only this, but I recommend again paying close attention to your local weather report.

It should also be noted that the best technique for bringing your saint john’s wort plants outside is to introduce them (in their pots) outside for an hour. And then increase the amount of time they spend outside each day by an hour until they have been outside for 8 hours.

This will “harden” your saint john’s wort plant, increasing its chances of fighting off diseases, insects, droughts, and wet conditions.

If you want to learn WHEN to plant ANY Flower in Iowa, head over to HERE and just type in the flower you want to grow.

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