How To Grow Watermelon in Canada | Complete Guide

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Although watermelon is often associated with hot, southern climates, Canadian gardeners can enjoy excellent harvests with proper planning. The key is choosing varieties suited to your growing season, providing plenty of warmth and sunlight, and allowing enough time for fruit to develop before autumn temperatures arrive.

Watermelon plants produce vigorous vines, deeply lobed leaves, yellow flowers, and fruit that varies widely in size, shape, rind pattern, and flesh colour. Some varieties produce compact, personal-sized melons, while others develop large fruit weighing several kilograms.

Growing watermelon from seed is especially rewarding because gardeners can choose from a wide range of varieties, including early-maturing selections suitable for shorter Canadian summers.

This complete guide explains how to grow watermelon from seed in Canada, including choosing varieties, indoor seed starting, direct sowing, transplanting, soil preparation, spacing, watering, fertilizing, pollination, fruit development, pest management, harvesting, and identifying when watermelon is ripe.

Watermelon Growing Guide at a Glance

Feature	Growing Requirement / Detail
Botanical Name	Citrullus lanatus
Plant Type	Warm-season annual fruiting vegetable; member of the Cucurbitaceae family
Sun Exposure	Full sun; at least 8 hours of direct sunlight daily is ideal
Soil	Fertile, well-drained soil rich in organic matter; pH approximately 6.0–6.8
Start Indoors	Approximately 3–4 weeks before the intended outdoor transplanting date
Direct Sow	After the last spring frost, when soil temperatures are consistently at least 21°C (70°F)
Sowing Depth	Approximately 2–2.5 cm (¾–1 inch)
Germination Time	Approximately 4–10 days in warm soil; slower in cooler conditions
Plant Spacing	Approximately 90–180 cm (3–6 feet), depending on variety and growing method
Row Spacing	Approximately 180–300 cm (6–10 feet) for vigorous vining varieties
Water Needs	Consistent moisture during vine growth, flowering, and fruit enlargement; avoid waterlogging
Difficulty Level	Moderate; requires warmth, careful timing, and adequate growing space
Container Friendly	Yes, with compact varieties, large containers, and suitable support

Can You Grow Watermelon in Canada?

Yes. Watermelon can be grown successfully in many parts of Canada, including Ontario, Quebec, British Columbia, the Prairie provinces, and Atlantic Canada.

However, watermelon requires more warmth than many other vegetables, and choosing an appropriate variety is especially important in regions with shorter summers.

Watermelon plants grow best during sustained warm weather. Cool temperatures can slow vine development, delay flowering, and extend the time required for fruit to mature.

In Southern Ontario, many early and mid-season watermelon varieties can produce mature fruit when planted at the correct time and grown in favourable conditions.

Gardeners in colder regions may benefit from starting seeds indoors, using black plastic mulch to warm the soil, or growing plants beneath temporary row covers early in the season.

For the best results, choose a variety with a maturity period suited to your local frost-free season.

Choosing the Best Watermelon Varieties for Canadian Gardens

Watermelon varieties differ in fruit size, flesh colour, sweetness, rind pattern, vine length, and days to maturity.

For Canadian gardeners, early-maturing varieties are often the most dependable choice.

Sugar Baby Watermelon

Sugar Baby is a popular heirloom watermelon known for its relatively small, round fruit, dark green rind, and sweet red flesh.

It is well suited to home gardens and is often recommended for regions with shorter growing seasons.

Sugar Baby typically matures in approximately 75–85 days under favourable conditions.

Crimson Sweet Watermelon

Crimson Sweet produces larger, round to slightly oval fruit with a light green rind marked by darker green stripes.

Its sweet red flesh makes it a popular choice for fresh eating.

Crimson Sweet generally requires approximately 80–90 days or longer to mature, depending on growing conditions.

Charleston Gray Watermelon

Charleston Gray is a traditional variety producing large, elongated fruit with a pale green-grey rind and red flesh.

Because of its substantial fruit size and longer maturity period, it is better suited to gardeners with ample space and a sufficiently warm growing season.

Yellow-Fleshed Watermelon

Yellow-fleshed watermelon varieties produce attractive fruit with golden-yellow flesh and a sweet flavour.

Maturity periods vary considerably, so gardeners should select varieties appropriate for their region.

Early-Maturing & Personal-Sized Watermelons

Compact, personal-sized watermelons are particularly useful for Canadian gardeners with shorter summers.

Some early varieties mature in approximately 65–75 days under favourable conditions.

These varieties can also be easier to manage in smaller gardens or on sturdy trellises.

Caribou Growing Note: Choose Early-Maturing Watermelons

For Canadian gardens with shorter growing seasons, early-maturing watermelon varieties offer the best chance of harvesting fully ripe fruit before autumn temperatures arrive. Sugar Baby and other compact, early varieties are often easier to grow successfully than very large, long-season watermelons.

When to Plant Watermelon in Canada

Watermelon is a heat-loving crop that should not be planted into cold soil.

Seeds germinate most reliably in warm conditions, and young plants can be damaged by frost or prolonged exposure to low temperatures.

Starting Watermelon Seeds Indoors

In Southern Ontario, indoor sowing often takes place in late April or May, depending on local frost dates and expected soil temperatures.

Starting seeds indoors provides a useful head start, particularly for gardeners growing longer-season varieties.

However, watermelon seedlings grow quickly and do not tolerate root disturbance well, so avoid starting them too early.

Direct Sowing Watermelon Outdoors

Direct sow watermelon seeds after the last spring frost, once soil temperatures are consistently at least 21°C (70°F).

In many Southern Ontario gardens, this may occur from late May into June, depending on weather conditions.

Direct sowing is generally most reliable in regions with long, warm summers.

Planning for Autumn Frost

Watermelon varieties may require approximately 65–100 days or longer to mature, depending on the variety and growing conditions.

Count backward from your region's expected first autumn frost and choose a variety that can mature within the available growing season.

Because cool late-season temperatures can slow ripening, allow a reasonable margin beyond the stated maturity period.

How to Start Watermelon Seeds Indoors

Starting watermelon seeds indoors can provide a valuable advantage in Canadian gardens, but careful handling is important because watermelon roots are sensitive to disturbance.

Individual pots are recommended.

1. Prepare Containers: Fill individual pots approximately 8–10 cm (3–4 inches) wide with clean, moist seed-starting mix.
2. Sow Seeds: Plant seeds approximately 2–2.5 cm (¾–1 inch) deep.
3. Maintain Warmth: Keep the growing medium around 27–32°C (80–90°F) during germination.
4. Maintain Moisture: Keep the growing medium evenly moist without waterlogging.
5. Provide Light: Once seedlings emerge, provide approximately 14–16 hours of light daily.
6. Thin Seedlings: Keep one healthy seedling per container.
7. Avoid Root Disturbance: Handle seedlings carefully and avoid unnecessary repotting.
8. Harden Off: Gradually acclimate seedlings to outdoor conditions before transplanting.

When using suitable grow lights, position them approximately 5–10 cm (2–4 inches) above young seedlings, adjusting as they grow and following the manufacturer's recommendations.

Transplant seedlings while they are young, actively growing, and not yet rootbound.

Read More | How to Start Seeds Indoors in Canada

Watermelon Germination Timeline & Troubleshooting

Watermelon seeds typically germinate within approximately 4–10 days when planted in warm, evenly moist growing media.

Germination may take longer when soil temperatures are below the ideal range.

Common Germination Problems

• Cold Soil: Low temperatures can delay germination or cause seeds to decay.
• Excessive Moisture: Waterlogged conditions can encourage seed rot.
• Dry Growing Medium: Seeds require consistent moisture during germination.
• Planting Too Deeply: Excessive sowing depth can prevent emergence.
• Old Seeds: Poorly stored or ageing seeds may have reduced viability.

For reliable germination, maintain warm conditions and avoid overwatering.

How to Direct Sow Watermelon Outdoors

1. Choose a Sunny Location: Select an area receiving at least 8 hours of direct sunlight daily.
2. Prepare the Soil: Incorporate finished compost and correct nutrient deficiencies where needed.
3. Create Planting Hills: Form low, broad mounds approximately 15–20 cm (6–8 inches) high if desired.
4. Sow Seeds: Plant approximately 3–4 seeds per hill, 2–2.5 cm (¾–1 inch) deep.
5. Water Gently: Keep the soil evenly moist until germination.
6. Thin Seedlings: Once established, retain the strongest 1–2 plants per hill, depending on available space and variety.
7. Maintain Moisture: Water regularly as vines develop.

Planting in hills can improve drainage and help the soil warm more quickly in spring.

Watermelons can also be planted successfully in traditional garden rows or raised beds.

Hardening Off Watermelon Seedlings

Before transplanting watermelon seedlings outdoors, gradually acclimate them to direct sunlight, wind, and changing temperatures.

Hardening off generally takes approximately 7–10 days.

1. Place seedlings outdoors in a sheltered, shaded location for a short period.
2. Gradually increase outdoor exposure each day.
3. Introduce direct sunlight slowly to prevent leaf scorch.
4. Protect seedlings from strong winds and cold temperatures.
5. Bring plants indoors if frost or unusually cold weather is expected.
6. Transplant once seedlings are sturdy and outdoor conditions are suitable.

Watermelon is especially sensitive to cold conditions, so avoid exposing seedlings to frost during hardening off.

How to Transplant Watermelon Outdoors

Because watermelon roots are sensitive to disturbance, handle seedlings gently and avoid breaking apart the root ball.

1. Choose a Sunny Location: Select an area receiving full sun.
2. Prepare the Soil: Incorporate finished compost and ensure good drainage.
3. Warm the Soil: Consider using black plastic mulch or another suitable soil-warming method.
4. Space Plants: Allow sufficient room for mature vines.
5. Dig Planting Holes: Make holes large enough to accommodate the root balls.
6. Transplant Carefully: Remove seedlings from their pots without disturbing the roots unnecessarily.
7. Plant at the Same Depth: Set seedlings at approximately their previous growing depth.
8. Water Thoroughly: Water immediately after transplanting.
9. Protect Young Plants: Use temporary covers if unusually cool weather is expected.

Avoid transplanting into cold, wet soil because this can slow growth and increase the risk of root problems.

Choosing the Best Location & Spacing

Watermelon plants produce vigorous vines that can spread several metres across the garden.

Providing adequate space is important for healthy growth, good airflow, and fruit development.

Ideal Growing Conditions

• Sunlight: Full sun, ideally at least 8 hours daily.
• Soil: Fertile, well-drained soil rich in organic matter.
• Soil pH: Approximately 6.0–6.8.
• Plant Spacing: Approximately 90–180 cm (3–6 feet), depending on variety.
• Row Spacing: Approximately 180–300 cm (6–10 feet) for vigorous vining varieties.
• Air Circulation: Provide sufficient space to reduce overcrowding.
• Drainage: Avoid locations where water collects after heavy rainfall.

Compact watermelon varieties may require less space than vigorous large-fruited varieties.

How to Keep Watermelon Plants Warm in Canadian Gardens

Warm soil and consistent summer temperatures are especially important for watermelon production.

In cooler Canadian regions, gardeners can use several methods to improve growing conditions.

Black Plastic Mulch

Black plastic mulch can help warm the soil during spring and early summer.

Warmer soil encourages stronger root growth and may help plants establish more quickly.

Raised Beds

Raised beds can improve drainage and may warm more quickly than surrounding garden soil.

Temporary Row Covers

Lightweight row covers or low tunnels can provide additional protection during cool early-season weather.

However, covers must be ventilated during warm weather and removed or opened when flowering begins to allow pollinating insects access to the flowers.

Wind Protection

Planting in a sunny location sheltered from strong winds can help reduce stress and improve growing conditions.

Caribou Growing Note: Warm Soil Makes a Difference

Watermelon is one of the most heat-loving crops in the vegetable garden. In cooler Canadian regions, black plastic mulch, raised beds, and temporary early-season covers can help improve growing conditions. Always provide ventilation during hot weather and allow pollinators access once plants begin flowering.

Watering Watermelon for Healthy Growth & Sweet Fruit

Watermelon plants require consistent moisture during vine growth, flowering, and fruit development.

Although established plants develop extensive root systems, prolonged drought can reduce growth, fruit size, and overall productivity.

Watering Guidelines

• After Transplanting: Water thoroughly to encourage root establishment.
• During Vine Growth: Maintain evenly moist soil.
• During Flowering: Avoid prolonged drought stress.
• During Fruit Enlargement: Provide consistent, deep watering.
• As Fruit Approaches Maturity: Avoid excessive irrigation, particularly when rainfall is sufficient.
• Avoid Waterlogging: Ensure soil drains freely.

As a general starting point, watermelon plants may require approximately 2.5–4 cm (1–1½ inches) of water per week from rainfall and irrigation combined, depending on weather, soil conditions, and plant size.

Water deeply rather than applying frequent, shallow irrigation.

Drip irrigation or watering at soil level can help reduce unnecessary leaf wetness.

Organic mulch can help conserve moisture and reduce competition from weeds.

Fertilizing Watermelon for Strong Vines & Healthy Fruit

Watermelon is a relatively heavy-feeding crop that benefits from fertile soil and balanced nutrition.

Adequate nutrients support healthy vine growth, flowering, and fruit development.

Before Planting

Incorporate finished compost into the planting area and correct nutrient deficiencies according to soil test recommendations.

During Early Growth

Young plants require sufficient nitrogen to support healthy leaf and vine development.

However, excessive nitrogen can encourage vigorous foliage at the expense of flowering and fruit production.

During Flowering & Fruit Development

Maintain balanced nutrition as plants begin flowering and setting fruit.

Potassium and other essential nutrients support normal plant development and fruit quality.

Additional fertilizer may be beneficial in nutrient-poor soils, but applications should be guided by soil fertility and plant condition.

Understanding Watermelon Flowers & Pollination

Successful pollination is essential for female flowers to develop into mature watermelons.

Male Watermelon Flowers

Male flowers develop on slender stems and produce pollen.

They often appear before female flowers, particularly during early vine growth.

Female Watermelon Flowers

Female flowers have a small, immature watermelon directly behind the flower.

When pollination is successful, this immature fruit begins to enlarge and develop.

How Watermelon Is Pollinated

Bees and other pollinating insects transfer pollen from male flowers to female flowers.

Watermelon flowers generally open in the morning, making this an important period for pollinator activity.

Encouraging pollinators and avoiding unnecessary pesticide applications during flowering can help improve fruit set.

How to Hand-Pollinate Watermelon

Hand-pollination can be useful when pollinator activity is limited or when female flowers repeatedly fail to develop fruit.

Step-by-Step Hand-Pollination

1. Identify a freshly opened male watermelon flower.
2. Identify a freshly opened female flower with a small immature watermelon behind it.
3. Carefully remove the male flower.
4. Remove its petals to expose the pollen-covered anther.
5. Gently transfer pollen onto the stigma inside the female flower.
6. Repeat with additional pollen if necessary.
7. Monitor the immature watermelon over the following days.

Successful pollination is usually followed by continued fruit enlargement.

If pollination is unsuccessful, the small immature watermelon may stop growing, turn yellow, and eventually decay.

Growing Seedless Watermelon: What Gardeners Should Know

Seedless watermelon varieties have special pollination requirements.

Most seedless watermelons are triploid hybrids and require pollen from a compatible seeded watermelon variety to produce fruit.

Because seedless varieties generally do not produce sufficient viable pollen, a seeded pollinizer variety must be grown nearby.

Gardeners should follow the specific planting recommendations supplied with their seedless watermelon seeds.

Seedless watermelon seeds may also have more demanding germination requirements than conventional seeded varieties.

For beginner gardeners, traditional seeded watermelon varieties are generally easier to grow.

Why Are My Watermelon Flowers Falling Off?

It is normal for male watermelon flowers to open briefly and then fall from the plant.

However, female flowers may also drop or fail to develop fruit when pollination is unsuccessful or growing conditions are unfavourable.

Possible Causes

• Normal Male Flower Drop: Male flowers naturally fall after flowering.
• Poor Pollination: Female flowers may fail to develop fruit without adequate pollen transfer.
• High Temperatures: Extreme heat can interfere with flower development and pollination.
• Water Stress: Inconsistent moisture can affect flowering and fruit set.
• Nutrient Imbalance: Excess nitrogen or nutrient deficiencies may reduce fruit production.
• Immature Plants: Young vines may produce male flowers before female flowers appear.

Maintain consistent moisture, encourage pollinators, and allow young plants sufficient time to develop.

How Watermelon Fruit Develops

After successful pollination, the small immature watermelon behind the female flower begins to enlarge.

As the fruit develops, it gradually takes on the characteristic shape, size, and rind pattern of its variety.

Watermelons may be round, oval, or elongated, with rinds ranging from dark green to light green or striped.

The flesh develops its mature colour and sweetness as the fruit ripens.

Unlike some fruits, watermelon does not continue to ripen significantly after harvest.

For the best flavour, allow fruit to reach full maturity on the vine whenever possible.

Should You Prune Watermelon Vines?

Pruning watermelon vines is generally optional.

Healthy vines produce leaves that support photosynthesis and provide energy for developing fruit.

Excessive pruning can reduce the plant's ability to mature its watermelons.

When Pruning May Be Helpful

• Removing damaged or diseased leaves.
• Managing vines that extend into pathways.
• Improving airflow in excessively crowded plantings.
• Redirecting vines away from neighbouring crops.

Some gardeners limit the number of developing fruit on large-fruited varieties to encourage larger individual watermelons.

However, fruit thinning is generally unnecessary for most home gardeners growing standard or personal-sized varieties.

Growing Watermelon Vertically

Compact and small-fruited watermelon varieties can be grown vertically on sturdy trellises.

This method can be useful for gardeners with limited ground space.

However, developing fruit can become heavy, so strong support is essential.

Tips for Vertical Growing

• Choose compact or small-fruited varieties.
• Use a sturdy trellis or support structure.
• Position the trellis in full sun.
• Train young vines gently as they grow.
• Use soft plant ties where necessary.
• Support developing fruit with slings made from breathable material.
• Monitor the structure regularly for stability.

Large-fruited watermelon varieties are generally less practical for vertical growing.

Growing Watermelon in Raised Beds & Containers

Watermelon can be grown in raised beds and large containers when provided with adequate growing space, soil fertility, and moisture.

Growing Watermelon in Raised Beds

Raised beds can improve drainage and may warm more quickly than surrounding garden soil.

• Choose a sunny location.
• Use fertile, well-drained soil.
• Allow adequate space for vines to spread.
• Direct vines over the edge of the bed when appropriate.
• Maintain consistent moisture.
• Apply organic mulch to conserve soil moisture.

Growing Watermelon in Containers

Compact varieties are the most practical choice for container growing.

• Container Size: Choose a container holding approximately 75–115 litres (20–30 US gallons) or more for a vigorous plant.
• Drainage: Ensure adequate drainage holes.
• Potting Mix: Use a fertile, well-draining potting mix.
• Sunlight: Provide full sun.
• Watering: Monitor moisture regularly because containers can dry out quickly.
• Fertilizing: Provide balanced nutrition throughout active growth.
• Support: Train vines onto a sturdy trellis or allow sufficient space for spreading.

Container-grown watermelon generally requires more frequent watering and careful nutrient management than plants grown directly in garden soil.

Common Watermelon Problems, Pests & Diseases

1. Cucumber Beetles

Cucumber beetles may feed on watermelon foliage and flowers and can spread certain plant diseases.

Protect young plants with insect netting where necessary, removing or opening covers when flowering begins to allow pollination.

2. Aphids

Aphids feed on plant sap and may cluster on tender leaves and growing tips.

Inspect plants regularly and manage small infestations before populations become severe.

3. Spider Mites

Spider mites may become problematic during hot, dry weather, causing fine stippling and discolouration on leaves.

Maintain appropriate moisture and monitor foliage regularly.

4. Powdery Mildew

Powdery mildew causes white, powdery patches on watermelon leaves and may reduce photosynthesis when infections become severe.

Provide adequate spacing, maintain airflow, and remove heavily affected foliage when appropriate.

5. Anthracnose

Anthracnose is a fungal disease that can cause leaf spots, stem lesions, and fruit damage.

Use healthy seed, rotate crops, maintain good airflow, and avoid unnecessary leaf wetness.

6. Fusarium Wilt

Fusarium wilt is a soilborne fungal disease that can cause yellowing, wilting, and plant decline.

Choose resistant varieties where available and avoid planting susceptible crops repeatedly in the same location.

7. Blossom-End Rot

Blossom-end rot can cause dark, sunken areas near the blossom end of developing watermelons.

It is associated with disrupted calcium movement within the fruit, often influenced by irregular moisture conditions.

Maintain consistent watering and avoid excessive fertilizer applications.

8. Poor Pollination

Female flowers may produce small watermelons that yellow, stop growing, and decay when pollination is insufficient.

Encourage pollinating insects and hand-pollinate when necessary.

9. Frost Damage

Watermelon is highly sensitive to frost.

Freezing temperatures can damage leaves, vines, and fruit, so harvest ripe watermelons before damaging autumn frost arrives.

How to Tell When Watermelon Is Ripe

Unlike some fruits, watermelon does not continue to ripen significantly after harvest.

Harvesting too early can result in pale, less sweet flesh, while leaving fruit too long may reduce eating quality.

1. Check the Tendril Near the Fruit

Look for the small, curly tendril closest to where the watermelon stem attaches to the vine.

As the fruit approaches maturity, this tendril often begins to dry and turn brown.

A fully dried tendril is a useful indicator of ripeness for many varieties, although it should not be used alone.

2. Examine the Ground Spot

The ground spot is the area of the watermelon that rests against the soil.

As the fruit matures, this spot often changes from pale white to creamy yellow or deeper yellow.

A yellow ground spot is a useful ripeness indicator for many varieties.

3. Look for a Dull Rind

Many watermelon varieties develop a slightly duller appearance as they mature.

The rind may lose some of its glossy appearance.

4. Check the Expected Maturity Period

Compare the number of days since planting or transplanting with the maturity period listed for the variety.

Remember that cool weather can delay maturity.

5. Use the Thump Test Carefully

Some gardeners tap watermelons and listen for a deep, hollow sound.

Although this method can provide clues, it is subjective and less reliable than combining several visual indicators.

For the best results, evaluate the tendril, ground spot, rind appearance, and expected maturity period together.

Caribou Growing Note: Don't Rely on the Thump Test Alone

For many watermelon varieties, a dried tendril near the fruit, a creamy-yellow ground spot, and a duller rind are useful signs of maturity. Check several indicators together rather than relying only on the sound of the fruit when tapped.

When to Harvest Watermelon in Canada

In Southern Ontario, harvesting commonly takes place from August into September, depending on planting dates, variety, and weather conditions.

In colder regions, early-maturing varieties may be harvested during late summer before temperatures begin to fall.

How to Harvest Watermelon

1. Check the fruit for several reliable ripeness indicators.
2. Use clean, sharp pruning shears or a knife.
3. Cut the stem approximately 2–5 cm (1–2 inches) above the watermelon.
4. Avoid pulling or twisting the fruit from the vine.
5. Handle watermelon carefully to prevent bruising or cracking.
6. Move harvested fruit to a shaded, protected location.

Harvesting at full maturity is important because watermelon does not become significantly sweeter after being removed from the vine.

How to Store Fresh Watermelon After Harvest

Freshly harvested watermelon is best enjoyed when fully ripe.

Whole watermelons can be stored for a limited period under suitable conditions, but storage life varies by variety and maturity.

Storing Whole Watermelons

• Keep fruit in a cool, dry location away from direct sunlight.
• Avoid prolonged storage at temperatures below approximately 10°C (50°F), which can cause chilling injury.
• Handle fruit carefully to prevent bruising or cracking.
• Inspect stored watermelons regularly for signs of decay.

Storing Cut Watermelon

Once cut, watermelon should be refrigerated promptly.

Store cut watermelon in a covered, food-safe container at 4°C (40°F) or colder.

For best quality, use refrigerated cut watermelon within approximately 3–4 days.

Freezing Watermelon

Watermelon can be frozen for use in smoothies, frozen drinks, and desserts.

Because watermelon contains a high percentage of water, freezing changes its texture, making it less suitable for eating fresh after thawing.

Can You Save Seeds from Watermelon?

Yes. Seeds can be collected from fully mature, seeded watermelons.

However, watermelon varieties can cross-pollinate with other compatible watermelon varieties.

Cross-pollination does not change the appearance or flavour of the fruit produced during the current season, but it can affect the characteristics of plants grown from saved seeds.

How to Save Watermelon Seeds

1. Choose a healthy, fully mature watermelon from a productive plant.
2. Cut open the fruit and remove mature seeds.
3. Separate seeds from the surrounding flesh.
4. Rinse and clean the seeds thoroughly.
5. Spread seeds in a single layer in a dry, well-ventilated location.
6. Allow seeds to dry completely.
7. Store dried seeds in a cool, dry, dark location.

For reliable seed saving, use open-pollinated varieties and maintain appropriate isolation from other compatible watermelon varieties.

Seeds saved from hybrid varieties may not produce plants identical to the parent.

Frequently Asked Questions About Growing Watermelon

Can watermelon grow successfully in Canada?
Yes. Watermelon grows successfully in many Canadian regions when provided with warm temperatures, full sun, fertile soil, and sufficient time to mature.

What is the best watermelon variety for Canada?
Early-maturing varieties such as Sugar Baby are often well suited to Canadian gardens, particularly in regions with shorter summers.

When should I start watermelon seeds indoors in Canada?
Start seeds approximately 3–4 weeks before the intended outdoor transplanting date.

When can I direct sow watermelon outdoors?
Direct sow after the last spring frost when soil temperatures are consistently at least 21°C (70°F).

How deep should I plant watermelon seeds?
Sow seeds approximately 2–2.5 cm (¾–1 inch) deep.

How long do watermelon seeds take to germinate?
Seeds typically germinate within approximately 4–10 days under favourable warm conditions.

Does watermelon need full sun?
Yes. Watermelon grows best with at least 8 hours of direct sunlight daily.

How far apart should watermelon plants be?
Space plants approximately 90–180 cm (3–6 feet) apart, depending on the variety and growing method.

How long does watermelon take to mature?
Most varieties require approximately 65–100 days or longer, depending on the variety and growing conditions.

Can watermelon grow in raised beds?
Yes. Raised beds are suitable when plants have fertile soil and sufficient room for vines to spread.

Can watermelon grow in containers?
Yes. Compact varieties can grow in very large containers with adequate drainage, moisture, and nutrients.

Can watermelon grow vertically?
Yes. Small watermelon varieties can be trained onto sturdy trellises, although developing fruit may require additional support.

Why are my watermelon flowers falling off?
Male flowers naturally fall after opening. Female flowers may fail to develop fruit because of poor pollination, temperature stress, or unfavourable growing conditions.

Why are my small watermelons turning yellow and dying?
Insufficient pollination is a common cause, although water stress and other environmental problems can also contribute.

Do watermelon plants need pollinators?
Yes. Bees and other insects normally transfer pollen between male and female flowers. Hand-pollination can be used when necessary.

Do seedless watermelons need pollination?
Yes. Most seedless watermelon varieties require pollen from a compatible seeded watermelon variety to produce fruit.

Should I prune watermelon vines?
Pruning is generally optional. Remove damaged foliage when needed, but avoid excessive pruning because healthy leaves support fruit development.

How do I know when watermelon is ripe?
Look for a dried tendril near the fruit, a creamy-yellow ground spot, a duller rind, and the expected maturity period for the variety.

Will watermelon ripen after harvesting?
No. Watermelon does not continue to ripen significantly after harvest, so fruit should be harvested when fully mature.

Can watermelon survive frost?
No. Watermelon is frost-sensitive, and freezing temperatures can damage vines and fruit.

How long can watermelon be stored?
Whole watermelons can be stored for a limited period under suitable conditions, while cut watermelon should be refrigerated and used within approximately 3–4 days.

Can I save seeds from watermelon?
Yes. Seeds can be saved from mature, open-pollinated varieties, although cross-pollination with other compatible watermelon varieties may affect future plants.

Grow Watermelon from Seed Today

Watermelon is a rewarding crop for Canadian gardeners who want to enjoy sweet, refreshing, homegrown fruit during the summer months. From compact Sugar Baby watermelons to larger traditional varieties, there are excellent options for gardens with different growing conditions and available space.

For the best results, choose a variety suited to your growing season, start seeds indoors when necessary, and plant outdoors only after the soil has warmed and the risk of frost has passed. Provide full sun, fertile soil, adequate growing space, and consistent moisture throughout flowering and fruit development.

Encourage pollinating insects, monitor developing fruit carefully, and use several ripeness indicators to determine the best harvest time.

Explore Caribou Seed Company's watermelon seeds and enjoy growing delicious, juicy watermelons in your own Canadian garden.

Featured Watermelon Seeds

Watermelon 'Sugar Baby' is a compact, early-maturing variety that produces small, round, 6–10 lb melons with deep green rinds and exceptionally sweet, juicy red flesh. Perfect for smaller gardens, raised beds, or container growing, this space-saving variety thrives in full sun and warm conditions.

Download | How to Grow Watermelon | Complete Growing Guide (PDF)

See You in the Garden!