How to Grow Watermelon
Watermelon At a Glance
Difficulty
Moderate
Category
Melon
Sun Exposure
Full Sun
Frost Tolerance
Frost Tender
Cold Hardiness
Survives to 2°C
Plant Family
Cucurbitaceae
Growing Season
Warm Season
Plant Lifecycle
Annual
How to Start It
★ Recommended for beginners
Watermelon cannot take frost, so sow it about 1 week after your last frost, once the soil has warmed to about 18°C (64°F), since cold soil rots the seed. Sow 3 seeds 2 cm deep in small groups 90 cm apart, and they sprout in 5 to 10 days. Keep the strongest seedling in each group and snip off the others.
Watermelons need heat, sun, room and about 85 days of warm weather, so pick a small, early variety if your summer is short. Small types can even climb a strong trellis if you hold each fruit in a cloth sling. Steady water while the fruit grows, then less at the end, makes the sweetest melons.
When To Start
Watermelon needs warmth. Wait until your last frost has passed and the soil has warmed before sowing.
We do not have exact sowing dates for this one yet.
When should you plant Watermelon?
Your planting dates depend on your local climate. Sign up and add your location to unlock personalized dates.
Your Watermelon Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
Your Watermelon Calendar
Set your location to turn these into exact dates and reminders.
Optional: start watermelon indoors in pots
3 weeks before your last frost· optional
Sow watermelon outdoors once the soil reaches 18°C
1 week after your last frost
See if watermelons are ripe: dry tendril, yellow ground spot
About 85 days after you plant it
Did you water your watermelon seedlings today? Keep the top of the soil damp until they are up and growing.
About 1 days after you plant it
Your watermelon vines are on the move! Water deeply at the base and give them room to spread.
About 38 days after you plant it
Your watermelons are growing! Set each fruit on a board or straw to keep it off wet soil.
About 67 days after you plant it
Picking time may be here: check your watermelon.
About 85 days after you plant it
The Journey Ahead
Watermelon's Lifecycle
Seedling
Mature Plant
Seed Production
Step 1
Prepare Your Space
2 cm
Seeding Depth
90 cm
Plant Spacing
180 cm
Row Spacing
Vertical Growing
Yes: small-fruited types up a strong trellis with fabric slings.
Succession Planting
No (one long crop).
Good Companions
Bad Companions
Step 2
Planting & Sprouting
Expect sprouts in 5–10 days
Growing Tips
- 1Give watermelons your hottest, sunniest spot, with at least 8 hours of sun a day.
- 2Mix plenty of compost into the soil, since they are hungry plants.
- 3Water deeply once or twice a week while the vines and fruit grow, then water less in the last 2 weeks so the sugars build up.
- 4Feed with compost tea or worm castings every 2 to 3 weeks until the fruit is full size.
- 5Cover young plants with row cover to keep off striped cucumber beetles, then take it off when the flowers open so bees can reach them.
- 6Set each melon on a piece of board or a bed of straw to keep it clean and dry.
Seedling Phase
Step 3
Growth & Maturity
~85
Days to Maturity
40 cm
Mature Height
300 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
Harvest Window
21 days
When to Pick
Pick when the curly tendril nearest the fruit dries brown and the ground-spot turns creamy yellow
How to Harvest
- 1Watermelons do not ripen after picking, so look for all the signs before you cut.
- 2The curly tendril closest to the melon dries and turns brown when it is ripe.
- 3The pale spot where the melon sits on the ground turns from white to creamy yellow, and the skin turns dull.
- 4Cut the stem with a knife, leaving 3 to 5 cm attached.
- 5Keep a whole melon at room temperature for up to 2 weeks, and cut melon in the fridge for a few days.
Step 5
Saving Seeds
How to Save Seeds
Watermelons are pollinated by bees and cross with other watermelons nearby, though not with cucumbers or other melons, so grow one variety or keep varieties about 800 m apart. Hybrid F1 seeds will not grow true, so save only from a variety that is not a hybrid. Take the dark seeds from a fully ripe melon, rinse off the pulp in a sieve, and spread them on a plate to dry for about 2 weeks. Store them labelled in a cool, dark, dry place, where they keep about 5 years.
Seed Production
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