Most often round, sometimes oval, and filled with flesh that is about 92% water, watermelon (Citrullus lanatus) is the summer fruit grown for sheer thirst-quenching refreshment, the usual harvest weighing 2 to 6 pounds. It asks for one thing above all, full sun and warmth, and repays it with fruit from midsummer to mid-autumn.
| Name | Citrullus lanatus |
|---|---|
| Family | Cucurbitaceae (gourd family) |
| Type | fruit |
| Height | 8 to 20 inches (20 to 50 cm) |
| Exposure | full sun |
| Soil | rich (the more, the better) |
| Sowing/planting | spring |
| Harvest | Midsummer to mid-autumn |
From sowing to harvest, here is how to grow watermelon.
Watermelon needs a lot of heat to germinate well, because seedlings can’t cope with frost at all.
Since it needs warmth, it is best to grow it in regions nearer the Equator, or at least in a greenhouse if you’re far from it.
Seedlings can be prepared indoors in nursery pots, in a warm and well-lit room. The ideal temperature range is between 72°F and 75°F (22°C to 24°C).
Depending on the climate in your area, sowing watermelon is best starting from the month of early spring under cover in nursery pots followed by transplanting in late spring after any risk of freezing has disappeared, or you can also wait for May and proceed to sow directly in the plot.
If sowing in nursery pots, plant for more or less 3 weeks before transplanting them to the ground. That’s why there is no point in sowing too early.
It is also possible to sow directly in the ground starting from late spring, if the area is prone to mild fall seasons.
This is the case in coastal areas such as climates nearer the Equator.
Since watermelon requires a lot of heat, it is recommended to place dark stones, shingles or tiles around the foot of the plant, they’ll store heat and share it to the plant.
If you’ve got the space in your garden or vegetable patch, you don’t need to trim or prune your watermelon to get nice watermelons.
Only prune for maintenance if you’ve got to control its spread to keep it from turning invasive and running over other growth.
Watermelon needs a lot of water to develop well and grow fat, especially in case of heat and/or extended dry spell.
The watermelon harvest is starts about 30 days after the blooming and extends over several weeks.
You should observe the watermelon well, because it really isn’t easy to determine how ripe it is. Don’t wait for the watermelon to break off from the stem on its own (as you would for pumpkin or butternut), when this happens it’s usually already overripe.
Best avoid watering during the last days before harvesting, and try to harvest in the afternoon instead of morning, so that the water content drops a bit.
After having been harvested, the watermelon won’t ripen any more, and it will keep for a few days or weeks depending on how it is stored.
The ideal preservation temperature ranges from 50° to 57°F (10°C to 13°C).
Even though the watermelon won’t ripen anymore after it’s been picked, its color and taste keep getting better for about a week, if placed at room temperature.
Not every watermelon suits every garden: short-season and compact sorts crop far more reliably under glass or in a cool summer, while the big oblong heirlooms need heat and room to sprawl. The table compares the varieties most often offered by seed catalogues and garden centres.
| Variety | Flesh colour | Fruit size | Ripening | Habit |
|---|---|---|---|---|
| Black Diamond | Red | Large, round | Late | Vigorous vine |
| Yellow Doll | Yellow | Small, icebox type | Early | Compact vine |
| Sugar Baby | Deep red | Small, icebox type | Early | Trailing vine |
| Bush Sugar Baby | Deep red | Small, icebox type | Early | Bush, short runners |
| Cal Sweet Bush | Red | Small to medium | Early | Bush, containers and small beds |
| Moon and Stars | Red | Large, round | Late | Vigorous vine, speckled rind |
| Crimson Sweet | Bright red | Medium to large, round | Mid-season | Vigorous vine |
| Sweet Beauty | Red | Small, oval icebox | Early | Compact vine |
| Sweet Siberian | Apricot-orange | Small to medium, oval | Early | Trailing vine, cool summers |
| Blacktail Mountain | Red | Small to medium, round | Very early | Trailing vine, cool summers |
| Golden Midget | Pink-red | Very small | Very early | Short vine, rind turns gold when ripe |
| Mini Love | Red | Small, personal size | Early | Short vine, small plots |
| Charleston Gray | Red | Large, oblong | Late | Vigorous vine |
| Jubilee | Red | Large, oblong | Late | Vigorous vine |
| Orangeglo | Orange | Large, oblong | Mid to late | Vigorous vine |
Watermelon follows a tight timetable from a warm windowsill in spring to a shaded store in autumn. The table gathers the key stages described above and the one point that matters at each of them.
| Stage | When | Key point |
|---|---|---|
| Sowing under cover in nursery pots | From early spring | 2 to 3 seeds per pot in a warm, well-lit room at 72–75°F (22–24°C) |
| Transplanting or direct sowing | late spring | Only once every risk of freezing has gone; 3 feet (1 metre) between plants |
| Watering | Every morning, all summer | Water the soil, not the leaves, especially in heat or drought |
| Harvest | Midsummer to mid-autumn, about 30 days after blooming | Pick in the afternoon; the fruit must feel very heavy |
| Keeping | A few days to a few weeks | Store cool at 50–57°F (10–13°C), dry and in the shade |
Miss the warmth at the start or the dry week at the end, and the rest of the timetable counts for little.
Native to Africa, watermelon is appreciated for its powerful thirst-quenching properties, as well as for its high vitamin content.
Just like melon, squash, pumpkins and other gourds, watermelon is part of the vast Cucurbitaceae family.
Watermelon is among the largest specimens of this family that brings together gourds and squash.
It is most often round, but can also be oval and record weight for a single watermelon is 65 pounds (30 kg)!
But most watermelons weigh between 2 and 6 pounds (1 to 3 kg).
It is known for the extremely high water content of its flesh (about 92%), which makes it one of the fruits that are the most loaded in water during the summer and is naturally very hydrating. Surprisingly, the seeds are where the vitamin C is found.
Watermelon is known to have powerful antioxidant activity.
The worst enemy of watermelon is cold temperatures: ensure it will never encounter them!
