Crops › Watermelon
How to grow Watermelon
in the UK
Sow April to May, plant out June to July, harvest August to September. About 100 days from seed to plate.
Watermelon. A proper challenge, this one, but oh, the rewards! Nothing beats cutting into your own homegrown melon on a warm day, a real taste of summer from the plot. They're a bit of a ground fruit, needing space and warmth, but if you've got a greenhouse or tunnel, it's a cracking project.
Sowing
Right, so watermelons, they're not for the faint-hearted, you know. We're talking April or May for sowing, indoors mind, 'cause they need a proper warm start. Pop a couple of seeds about 2cm deep in a small pot of good compost. Keep 'em somewhere warm, like on a heated propagator or a sunny windowsill, around 20-25°C if you can manage it. Once they've germinated, thin 'em to the strongest seedling. No point faffing about with direct sowing here in the North East, it's just too cold for them early on, and you won't find plug plants for these either.
Growing on
Once your seedlings are big enough to handle, pot 'em on into slightly larger pots. Give 'em a bit of space on the windowsill or in the greenhouse. Hardening off isn't really needed if they're going straight into a warm greenhouse or polytunnel, which, to be honest, is where they really want to be. Plant 'em out after all danger of frost has passed – usually mid to late May for us up here. Give each plant about a metre square, they spread out a fair bit, these ground fruits.
Looking after it
Watering's key, like I say, especially when they're fruiting. Give 'em a good deep soak rather than little dribbles. And a high-potash feed every couple of weeks once flowers appear really helps. Train those lateral shoots, just to keep 'em tidy and get the light to the fruits. Keep an eye on airflow too, proper important in a greenhouse to stop troubles brewing.
What goes wrong
Now, for problems, red spider mite can be a proper pain in a warm, dry greenhouse. Keep the humidity up a bit if you can, and check under the leaves regular. Aphids can pop up too, just squish 'em or wash 'em off with a bit of soapy water. Growing marigolds or basil nearby can sometimes help keep the pests away, you know, a bit of companion planting.
Harvest
You're looking at August or September for harvest, about 100 days from when you sowed 'em. The trick is knowing when they're ripe. The tendril nearest the fruit should be dry and curled, and the patch where it sits on the ground should be yellow. Give it a gentle tap too, should sound a bit hollow. Cut 'em from the vine with a bit of stem attached. They'll keep a week or two at cool room temperature, a cracking treat.
My tip for watermelons is to make sure you've got good sturdy supports for the developing fruits, especially if they're hanging. A little net hammock works a treat, stops 'em snapping off the vine under their own weight.
Dates for your plot
Type the first half of your postcode and the plant-out advice shifts to your area's typical frost dates.
Varieties, and whether the club would grow them again
| Variety | Club verdict |
|---|---|
| Sugar Baby This is one of the classic small-fruited varieties, really popular for getting a decent crop in a UK greenhouse. You'll get lovely sweet melons that ripen up a bit quicker than some of the bigger ones. | No club votes yet |
| Blacktail Mountain A hardy little early melon, Blacktail Mountain gives you proper sweet red flesh even in our trickier climate. It's a good choice if you're keen to try watermelons under cover for the first time. | No club votes yet |
| Crimson Sweet This one's well-regarded for its cracking flavour and vibrant red flesh, a proper treat from the greenhouse. It's a reliable early performer, giving good yields of medium-sized fruits. | No club votes yet |
| Mini Love F1 A really compact plant, Mini Love F1 is ideal for smaller spaces in your polytunnel or greenhouse. You'll get lovely personal-sized watermelons with a sweet, crisp taste. | No club votes yet |
| Yellow Baby If you fancy something a bit different, Yellow Baby delivers sweet, yellow-fleshed melons that are a real talking point. It's an early variety that does well when grown under protection. | No club votes yet |
| Sweet Siberian This variety is known for its unusual orange flesh and really sweet flavour, a bit of a fancy one. It's an early melon that's surprisingly adaptable to our cooler greenhouse conditions. | No club votes yet |
| Ali Baba A vigorous grower, Ali Baba produces good yields of oblong fruits with excellent flavour. It's an early-maturing type, making it a solid choice for a UK covered plot. | No club votes yet |
| Desert King Despite the name, Desert King can perform well in a UK greenhouse, offering pale green, sweet-fleshed fruits. It's a dependable early variety if you give it the warmth it craves. | No club votes yet |
| Little Darling True to its name, Little Darling gives you small, round fruits with a proper sweet flavour, perfect for one or two people. It's a great early choice for a prolific harvest under cover. | No club votes yet |
| Moon & Stars This one's a stunner, with dark green skin speckled like stars and a big yellow 'moon' patch. The flavour's cracking too, making it a bit of a showstopper for your greenhouse. | No club votes yet |
| Golden Crown Golden Crown offers beautiful yellow-skinned fruits with sweet red flesh, a real eye-catcher on the plot. It’s an early variety that responds well to the warmth of a tunnel or greenhouse. | No club votes yet |
| Tigrimini A really pretty little melon, Tigrimini has striped skin and lovely sweet red flesh, ideal for individual servings. It's an early producer, perfect for getting those first watermelons from your greenhouse. | No club votes yet |
Votes are members rating varieties in their Seed Tin, one vote per gardener. Tap a variety for the full page and where to buy.
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Cook the harvest
A classic pavlova crowned with lightly sweetened whipped cream and a tumble of fresh hardy kiwi berries. The tiny, grape-sized fruit are eaten skin and all, and their sweet-tart flavour and vivid green flesh are perfect against the white meringue and cream. A stunning autumn dessert.
90 min · mediumA beautiful, deeply coloured cold soup of blended watermelon, ripe tomatoes, cucumber, red pepper, and sherry vinegar — a refreshing and unexpected starter that is sweet, savoury, and perfectly acidic all at once. Served ice-cold in small bowls with a drizzle of olive oil and a few mint leaves, it is the most impressive thing you can make with a watermelon.
20 min · easyJuicy chunks of watermelon and golden, salty halloumi threaded onto skewers and grilled until the cheese is deeply golden on the outside while the watermelon caramelises at its edges — a combination that sounds unusual and tastes extraordinary. Drizzled with honey, scattered with fresh mint and chilli flakes, and eaten straight from the grill, these are the definitive summer party food.
25 min · easyA crisp pastry tart filled with a thick vanilla custard cream and topped with halved fresh hardy kiwi berries. The jewel-like green berries are visually spectacular against the pale cream filling. A proper patisserie-style tart that showcases the unusual berries at their best.
55 min · mediumWatch for, and grow alongside
Companions: marigold, basil
Questions people ask
When do you sow Watermelon in the UK?
Sow Watermelon from April to May. Plant out June to July, after the last frost.
How long does Watermelon take from sowing to harvest?
Roughly 100 days, with the harvest August to September.
Which Watermelon varieties do gardeners grow again?
Club members rate every variety they grow. This page shows the grow-again votes for Sugar Baby, Blacktail Mountain, Crimson Sweet, Mini Love F1 and more.
Track your Watermelon from packet to plate
Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.
Allotment keeper in the North East of England, the voice behind the Tony C Smith YouTube channel, and the gardener who built GrowMore CookMore. Club numbers on this page update as members log their plots. Last updated 3 September 2026.