How to know when to plant certain seeds in the DC region as the climate changes

With spring in full bloom and summer around the corner, gardeners around the D.C. region are hard at work planting seeds and tending to their plants.

But how do you know when is the best time to bury a particular seed? It’s determined by planting zones.

Packages of seeds often include a map of the U.S. divided into zones. Each zone indicates which plants will do well in that area and when to plant them. The planting zones are based on the average lowest winter temperature in an area.

“More importantly, it’s based on climate data — which, as you know, is not weather data, it’s climate — so it’s looking at long-term weather information over a period of time,” 7News First Alert Chief Meteorologist Veronica Johnson said.

And those zones are changing as the climate does.

“Over the U.S., about two thirds of the locations since 1960 have shifted into warmer zones, because winters just aren’t getting as cold,” Johnson said.

For gardeners, that means some plants, such as beans and Brussels sprouts, can be planted earlier.

“What folks were putting in the ground in North Carolina, now we can start putting on the ground here in D.C. and Maryland,” Johnson said. “Maybe another 30 years from now, we’ll continue to see that shift northward, where plants in North Carolina we’re able to see thrive are starting to shift more to the north.”

After this past winter’s snow and ice that seemed to never melt, Johnson said it’s important to remember that this data is collected over decades.

“It’s not a single winter and it’s not any single storm,” Johnson said. “This is over a 30-year period with that average coldest temperature to help gardeners know what they can put in the ground and when they can put it in the ground.”

Johnson said the best way to ensure you’re planting the right seeds at the right time is to read the information on the back of the seed packages — and not to use old seeds, because they might have outdated information.

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