Watermelon
Citrullus lanatus · Cucurbitaceae
- Start indoors3–4 weeks before the last frostMar 13 – Mar 26
- Sow outdoors2–3 weeks after the last frostApr 24 – May 7
- Plant out2–3 weeks after the last frostApr 24 – May 7
- Space0.9–1.8 m (3–6 ft) apart
- Harvest70–100 days after plantingJul 3 – Sep 5
Description
Watermelon is a large, juicy fruit characterized by its green rind and sweet, watery, red or pink flesh. It is particularly known for its refreshing taste and high water content, typically around 90%.
Growing Conditions
30–60 cm (12–24 in) tall, 1.8–4.5 m (6–15 ft) wide
- Smallest
- Largest
Full sun, 8+ hours
Moderate
Keep evenly moist, not soggy.
Ideal 21–32 °C (70–90 °F)
Survives down to 0 °C (32 °F).
pH 6–7 · acidic to neutral
Where it Grows
Planting
When to Plant
- Spring: Ideal planting time is after the danger of frost has passed and soil temperatures are consistently above 70°F (21°C).
How to Plant
- Choose a sunny location with well-drained soil.
- Prepare the soil by tilling and adding organic matter.
- Plant seeds 1 inch deep and 36-42 inches apart in rows.
- Water deeply after planting.
Growth Timeline
- Germination 4–10 days
- Seedlings indoors 4–6 weeks
- Growing in the garden 70–100 days
- Harvest 2–4 weeks
Planting Calendar
- Start seeds indoors: 3–4 weeks before the last frost
- Sow outdoors: 2–3 weeks after the last frost
- Plant outdoors: 2–3 weeks after the last frost
- Germination: 4–10 days
- Start indoors: Mar 13 – Mar 26
- Sow outdoors: Apr 24 – May 7
- Plant out: Apr 24 – May 7
- Harvest: Jul 3 – Sep 5
Care
Care Calendar
- Feed · Apr 17 – Jun 4
Mix compost into the soil at planting, then side-dress lightly when vines begin to run. - Thin · May 1 – May 21
Once true leaves appear, keep the strongest one or two seedlings in each planting hill. - Mulch · May 1 – May 28
After the soil warms, spread straw around the vines, keeping it clear of the stems.
Watering
- Water regularly, especially during dry spells; aim for about 1-1.5 inches of water per week.
Weeding
- Regularly check for weeds and remove them as they compete for nutrients and water.
Mulching
- Apply organic mulch around plants to conserve moisture and suppress weeds.
Fertilizing
- Use a balanced fertilizer when seedlings are established and again when they start to produce fruit.
Thinning
- Thin seedlings to one per hill when they reach about 4 inches tall to ensure adequate space for growth.
Pest Management
- Monitor for pests such as aphids and beetles; consider using organic insecticidal soap or neem oil.
Harvesting
- Harvest when the tendril nearest the fruit turns brown and the fruit shows a dull sheen.
Growing in Containers
Grows well in a pot of at least 40 litres (11 US gallons), with drainage holes. Best kept outdoors.
Propagation
From seed
- Start seeds indoors in individual pots 3–4 weeks before the last frost, or sow outdoors once the soil reaches about 21°C (70°F).
- Sow seeds 2–3 cm (about 1 inch) deep.
- Keep the soil warm and evenly moist until seeds sprout.
- Harden off indoor-grown seedlings and plant them out after the last frost, taking care not to disturb their roots.
- Thin outdoor-sown seedlings to one or two plants per hill.
Companion Plants
Good neighbors
- Borage: Its flowers attract bees that help pollinate watermelon blossoms.
- Nasturtiums: Their flowers attract pollinators when planted near watermelon vines.
Common Problems
- Yellowing leaves
- Sticky residue on leaves
- Black sooty coating
- Curled or cupped leaves
Aphids are small, soft-bodied insects that feed by piercing plants and drawing out sap. The group includes many…
- Holes in leaves
- Wilting
- Stunted growth
- Insects visible on the plant
Cucumber beetles are small leaf beetles that feed on cucumbers, melons, squash, pumpkins, and other cucurbits. In…
- White powdery coating
- Yellowing leaves
- Curled or cupped leaves
- Distorted new growth
Powdery mildew is a group of fungal diseases, not a single species. Different fungi infect different hosts, including…
- Yellowing leaves
- Wilting
- Stunted growth
- Leaves dropping
Fusarium wilt is a soilborne fungal disease that affects many garden crops and ornamentals, including tomatoes, beans…
- Spots on leaves
- Brown or crispy leaf edges
- Bleached or scorched patches
- Leaves dropping
Anthracnose is a name for several fungal diseases, not a single species. Depending on the plant, the cause may be a…
- Blossom end rot
- Powdery mildew
- Fruit fly infestation
- Root rot
Nutrition
Nutritional Benefits
- Low in calories and fat
- High in hydration
- Source of vitamins A and C
Nutritional Composition (per 100g)
| Nutrient | Amount |
|---|---|
| Calories | 30 kcal |
| Water | 91.45 g |
| Carbohydrates | 7.55 g |
| Protein | 0.61 g |
| Fat | 0.15 g |
| Fiber | 0.4 g |
| Vitamin C | 8.1 mg |
| Vitamin A | 18 mcg |
Varieties
Its manageable fruit size makes it a popular choice for home gardens.
- small fruit
- dark rind
This widely grown variety produces round fruit with sweet red flesh.
- striped rind
- red flesh
Its large, elongated melons need plenty of room and a long season.
- oblong fruit
- pale rind
This variety is best suited to gardens with a long, warm growing season.
- large fruit
- striped rind
Yellow speckles on the rind give this large-fruited variety its distinctive look.
- heirloom
- spotted rind
Its relatively short time to maturity makes it useful in cooler regions.
- early
- small fruit
This small-fruited variety offers yellow flesh and a relatively early harvest.
- yellow flesh
- early
More about varieties
- Seedless Watermelon
- Picnic Watermelon
- Icebox Watermelon
- Yellow Watermelon
- Orange Watermelon
Health Benefits
- Hydration due to high water content
- Rich in antioxidants, including lycopene
- Supports heart health and may help lower blood pressure
Fun Facts
- Watermelon is 92% water!
- The largest watermelon ever recorded weighed 350.5 pounds (158.8 kg).
- Watermelon seeds can be roasted and eaten as a snack.
- Watermelon is not a vegetable but a fruit, specifically a berry!
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