When to Plant Dahlias in Monmouth, OR

One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Monmouth should be used to determine when to plant dahlias.


Planting Calendar for Dahlias

Frost tolerance for dahlias: Not tolerant of frost.
When to plant: After all chance of frost has passed.

It's probably not a good idea to plant dahlias until after the last frost when the weather gets warmer because they do not do well in cold weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant dahlias
Possibly ok, but a risky time to plant dahlias
Probably not a good time to plant dahlias

The earliest that you can plant dahlias in Monmouth is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant dahlias and expect a good harvest is probably August. If you wait any later than that and your dahlias may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your dahlias indoors.

Last Frost Date

In Monmouth the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Monmouth may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Monmouth last frost occurs after March 15 so be sure to be ready to protect your dahlias in the event of a late frost.

USDA Zone Info for Monmouth

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)March 15
Average Date of First Frost (fall)November 15
Lowest Expected Low15°F
Highest Expected Low20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Monmouth

You may be interested in your other planting guides for Monmouth.