How long does it take to grow a watermelon?
Written by
Olivia Mitchell
Reviewed by
Prof. Martin Thorne, Ph.D.Growing watermelon is heavily dependent on the variety and when you expect to eat them at peak ripeness. Early varieties like ‘Sugar Baby' will have fruit within 75 days. Heirloom varieties like ‘Moon and Stars' need 95 or more days to deliver fruit. I have experience timing crops from seed to harvesting them in eight states, climate and care are the main thing that shifts these timelines; more than the seed packets give credit.
Germination to First Flowers
- Seeds sprout in 4-10 days at 70°F (21°C) soil temps
- Vines produce male flowers first, females follow 7-10 days later
- Hand-pollinate daily during this phase to maximize fruit set
Fruit Development Stages
- 20-25 days: marble-sized fruit with visible stripes
- 35-45 days: rapid expansion phase (1+ lb/week gain)
- Final 10 days: sugar concentration peaks (Brix 10-12%)
Signs of ripeness outweigh calendar dates. The ground spot generally will change from white to a buttery yellow color. Also, the nearest tendril will brown down fully. I once picked ‘Crimson Sweet' in about 80 days and ended up with immature flesh. Now, I wait for the natural sign that the vine is ready to let go, near the fruit.
Accelerate growth using black plastic mulch, raising soil temperatures to 10°F (5.5°C). In my Missouri trial, ‘Sugar Baby' matured 12 days earlier under these conditions. But don't over-fertilize, too much nitrogen encourages leafy growth rather than flowers and fruit. Always use a balanced fertilizer like a 5-5-5.
Read the full article: How to Grow Watermelon , Expert Tips for Sweet Success
