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The best time to plant watermelon in Maryland is from late May through mid-June, once the soil has warmed to at least 70°F and all danger of frost has passed.
Timing is everything when you plant watermelon in Maryland, because this heat-loving fruit absolutely hates the cold.
If you plant watermelon in Maryland too early, the seeds rot in cool, damp soil, and if you wait too long, your melons won’t have enough time to ripen before the first fall chill.
In this post, we’ll walk through exactly when to plant watermelon in Maryland, how to pick the right window for your region, and how to set your crop up for a sweet, juicy harvest.
Let’s dig in.
When to Plant Watermelon in Maryland
You should plant watermelon in Maryland between late May and mid-June for the best results.
Here’s what makes that window so important:
1. Maryland’s Last Frost Date Sets the Clock
Maryland’s last frost date varies across the state, and that date is your starting point.
In central Maryland, including Baltimore and Annapolis, the last frost usually falls around mid-April.
On the Eastern Shore and in southern Maryland, it can be as early as late March or early April.
In western Maryland, though, the last frost can hang on until mid-May, so the planting window shifts later.
Most gardeners plant watermelon in Maryland about four to six weeks after that last frost date.
Transplants go in the ground sooner than seeds since seedlings are more cold-sensitive, but the same general rule applies.
2. Soil Temperature Matters More Than the Calendar
Watermelon seeds won’t germinate in cold soil, no matter what the calendar says.
When you plant watermelon in Maryland, check that your soil has reached at least 70°F, ideally closer to 75°F.
You can grab an inexpensive soil thermometer and check a few inches down before you plant.
If your soil is still in the low 60s, wait another week or two, because cold, wet soil is the fastest way to lose a crop.
Once soil temps hold steady above 70°F, you’re clear to plant watermelon in Maryland with confidence.
3. Starting Seeds Indoors Gives You a Head Start
One of the best tricks for Maryland gardeners is starting watermelon seeds indoors.
Begin your seeds about three to four weeks before your target transplant date.
So if you plan to plant watermelon in Maryland around late May, start seeds indoors in late April or early May.
Use biodegradable pots since watermelon roots resent disturbance.
Harden the seedlings off for a week before you plant watermelon in Maryland outdoors, and wait for a stretch of warm, settled weather.
Regional Planting Tips for Watermelon in Maryland
Maryland isn’t one single climate, so your exact planting date depends on where you live.
Here’s how to fine-tune things region by region.
1. Central Maryland and the Baltimore Area
In central Maryland, aim to plant watermelon in Maryland between late May and early June.
This area sits in a moderate zone where frost usually exits by mid-April, but nighttime temps can still dip into the 40s well into May.
Waiting until Memorial Day weekend is a safe bet for seeds and transplants alike.
2. Southern Maryland and the Eastern Shore
These regions warm up first, thanks to the Chesapeake Bay and the Atlantic influence.
You can often plant watermelon in Maryland here by mid-to-late May.
The longer growing season also means your melons have more time to size up and ripen fully before fall.
Just watch for late cold snaps, which can still sneak in.
3. Western Maryland and Higher Elevations
In the mountains, the growing season is shorter and cooler.
Wait until early to mid-June to plant watermelon in Maryland here, and choose short-season varieties like Sugar Baby or Blacktail Mountain.
Starting seeds indoors is almost mandatory in western Maryland if you want ripe fruit.
A black plastic mulch can also warm the soil and buy you a few extra weeks.
How to Plant Watermelon in Maryland for a Big Harvest
Timing is only half the battle, so here’s how to plant watermelon in Maryland the right way.
1. Pick a Sunny, Well-Drained Spot
Watermelons need at least eight hours of direct sun and loose, well-drained soil.
Plant watermelon in Maryland on raised mounds or hills to improve drainage and warmth.
Space hills about six feet apart so vines have room to sprawl.
2. Warm the Soil With Black Plastic
Laying black plastic mulch a couple of weeks before you plant watermelon in Maryland can raise soil temps by several degrees.
That extra warmth speeds germination and gives your plants a strong start.
It also keeps weeds down and holds moisture in during dry spells.
3. Water Deeply and Consistently
Once your plants are in, water deeply about once a week, aiming for an inch of water each time.
When you plant watermelon in Maryland, remember that consistent moisture matters most during flowering and fruit set.
Cut back slightly as the melons ripen, since too much water near harvest can dilute the sugars.
So, When Should You Plant Watermelon in Maryland?
You should plant watermelon in Maryland between late May and mid-June, once the soil hits 70°F and frost is long gone.
Central Maryland gardeners can target Memorial Day weekend, southern and Eastern Shore growers can start a bit earlier, and western Maryland should wait until early June.
Start seeds indoors for a head start, warm your soil, and pick a sunny spot, and you’ll be rewarded with sweet, homegrown melons by late summer.
Happy planting.