Garden Guide: Is it safe to plant your summer garden?

The start of May is safe for most of us to start our summer gardens, but there are a few cold pockets that have to wait a bit longer before planting in the ground.

Alex Calamia

May 3, 2024, 9:31 AM

Updated 162 days ago

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You may have heard gardeners recommend waiting until Mother's Day before starting a garden. It's easy to remember, but it's not the most accurate because the date changes every year, ranging from as early as May 8 to as late as May 14. The start of May is safe for most of us to start our summer gardens, but there are a few cold pockets that have to wait a bit longer before planting in the ground.

The problem with the average last freeze date

Most summer plants will die if they freeze, so the last freeze date is a great tool for gardeners, but it's not the final say in when it's time to start a garden. This date is actually usually too early to start a garden. One reason is right in the name! It's just an "average date" based on 30 years of climate data. Cold weather happens before and after this date. I prefer to use the "latest 35 F." I feel this is a better guideline. Here are those dates for a few data sites across the Tri-state area.
Latest 35 F since 2000
ISLIP, NY - May 9
WESTHAMPTON, NY- June 7
MONTAUK, NY - May 8
BRIDGEPORT, CT - May 9
DANBURY, CT - June 1
NEWARK, NJ - May 10
TRENTON, NJ - May 22
ATLANTIC CITY - May 9
CENTRAL PARK, NY- May 9
PASSAIC COUNTY NJ - June 1
ORANGE COUNTY AIRPORT, NY - June 1
WESTCHESTER AIRPORT, NY- May 21
Check out our forecast around these dates, and if you don't see temperatures in the 30s at night, you are safe to grow your tender summer plants. Our 10-day forecast goes out to the middle of May as of writing this article, so it is now looking safe to plant in urban parts of New Jersey, the 5 boroughs, Nassau, Suffolk and Western counties, and the Hudson Valley along and south of the I-287. It also looks safe to start planting south of Merrit Parkway in Connecticut.

Frost does not deserve its bad reputation

The presence of frost on your windshield or grass is usually a sign that it's too cold for your tender plants, and you may have even noticed that it forms when air temperatures are as warm as the upper 30s. The frost itself is not damaging your plants! It's just a symptom of the problem. Frost develops in the presence of humidity and freezing temperatures. The official air temperature doesn't have to drop below freezing on a calm and clear night for frost to develop because the ground releases heat faster.
You can save your plants from frost damage on nights like these by tucking them under a porch or tree where temperatures remain a few degrees warmer.

Is it hot enough yet?

There are plenty of plants and some summer flowers that love cooler weather. Leafy greens prefer cooler weather, and petunias and geraniums can handle light freezes. These are totally safe to plant now. In fact, May is too warm to grow some leafy greens from seed because they'll become bitter in the heat. There are some plants like tomatoes, eggplant, and summer annuals like caladiums, Madagascar periwinkle, coleus, sunflowers, and squash that require a lot of heat to grow quickly. I like to buy these plants this time of the year, but if they aren't rootbound in their pots, I'll delay planting them so I can place them in a warm part of my garden. It gives me more time to brainstorm where I'd like to put them too!