Here is the BEST Time to Plant Lupin in Montana (2023 Guide)

Do you want to grow lupin in Montana, but don’t know when to plant them?

Planting lupin is not as easy as it seems.

Here’s why:

  • Lupin are not able to survive frost or cold weather under 50 degrees Fahrenheit.

So if you plant them outside too early in the fall they will die. And if you plant them too late, your lupin won’t produce a bloom.

Today, I’m going to teach you the ideal time to plant lupin in Montana:

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

When to Plant Lupin in Montana

As you may have already guessed, you need to pay very close attention to your local weather in the fall. 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 lupin outside in Montana!

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

Montana Last & First Frost Dates

Montana 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 lupin planted outside in Montana 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 lupin?

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

  • If lupin are in pots, bring them inside
  • If lupin are in the ground, cover them in burlap and hope they survive

Also, make sure not to plant your lupin in your garden too late.

  • Planting lupin too late will cause small blooms or even worse, no blooms.

When Should You Start Your Lupin Seeds Indoors?

Depending on the type of lupin, it takes roughly 98-112 days (14 to 16 weeks) to grow lupin from seed indoors and then transplant them to your garden. And then another 2 to 3 months to bloom!

For a specific date that you should start lupin seeds indoors you should:

  • Find the last average frost date HERE
  • And then subtract 98 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 lupin 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 lupin plant, increasing its chances of fighting off diseases, insects, droughts, and wet conditions.

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

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