How to Pick a Sweet Watermelon (Tarbooz): Tap, Spot and Weight Tests

Tap it, turn it, lift it: a sweet watermelon sounds deep and hollow, has a creamy-yellow ground spot and feels heavy for its size. That’s how to pick a sweet watermelon in under a minute. Here’s what each test really tells you, how to store watermelon (tarbooz) in the fridge once it’s cut, why a watermelon goes slimy, and the truth about “injected” red ones.

How to pick a sweet watermelon at the stall

If you’ve ever lugged a heavy melon home in a rickshaw, split it on the kitchen floor and found pale pink, watery flesh with no taste at all, you already know why a minute of checking at the stall is worth it. A watermelon doesn’t get sweeter after it’s picked. It can soften and change colour a little, but the sugar is fixed the day it leaves the vine. So everything you check is really asking one question: was this one picked ripe?

1. Turn it over and find the ground spot. That’s the pale patch where it sat on the soil. Creamy yellow or even buttery orange means it ripened in the field. White or pale green means it was picked early.
2. Look at the rind. A ripe one is dull, not shiny. Shiny skin usually means underripe.
3. Check for webbing. Brown, rough, net-like scars on the skin are marks left where bees worked the flower. Stall wisdom says more webbing, sweeter fruit. It’s a hint, not a rule, but it never means a bad melon.
4. Lift two of the same size. Pick the heavier one. Water makes up about 92% of a watermelon, so weight means juice.
5. Tap with your knuckles. Listen for a deep, hollow thud, a bit like knocking on a door. A high, tinny “ping” suggests underripe. A flat, dead thud suggests overripe and mealy.
6. Check the stalk end. A dry, brown stalk is good. A green, fresh stalk means it was cut before it was ready.
7. Press the ends. They should be firm. Soft spots, cracks or leaks are a no.

Pass three or four of these and you’ve got a good one. None of them alone is perfect, and even farmers who grow watermelons for a living cut the odd dud, so don’t blame yourself when a melon that ticked every box turns out pale and watery at home. It happens.

What the tap test actually tells you

Sound travels differently through firm, juicy flesh than through soft, mealy flesh, and a ripe watermelon is full of water under pressure, so it rings with a low, open tone; an overripe one has broken-down, spongy flesh that deadens the sound.

The catch? Practice. Tap a few melons in a row and compare them, and the one that sounds a bit deeper than the rest is usually your pick; if you can’t hear any difference, lean on the ground spot and weight instead, which are easier to read.

Round or long, striped or dark: does the type matter?

Stalls in Pakistan and India mostly sell dark green or striped oval melons, and some sell smaller round “sugar baby” types. Seedless watermelons also show up in bigger cities, and they’re not injected or modified in any scary sense but bred so the seeds don’t mature, and the few soft white ones inside are harmless.

Within one type, bigger isn’t sweeter: a medium melon that’s heavy for its size usually beats a giant one. Round melons are sometimes said to be sweeter and long ones more watery, but it’s a loose pattern at best.

Injected or coloured watermelon: can you tell?

People worry that sellers inject red dye or sugar syrup, and videos claiming to catch them at it go round every summer, but most of what’s shown can be explained by ordinary ripeness, variety and the fact that real watermelon juice is strongly coloured. Here’s the honest view.

• An injection leaves a hole in the rind. Look for a small puncture, often near the stalk, sometimes with a wet or mouldy ring. A melon with a hole also rots fast, which makes the trick hard to pull off.
• The cotton-ball rub (rubbing cotton on the flesh to see if red comes off) proves little. Natural watermelon juice stains cotton pink too. A deep, unnatural red that bleeds heavily into the cotton or water is a reason to throw it away, not to test further.
• Very pale flesh with a fibrous, yellowish core and hard white seeds means underripe, not faked.

If a cut melon smells chemical, fizzy or sour, don’t taste it, don’t give it to the children to “see if it’s okay”, and don’t try to save the good-looking half by cutting away the bad part, because the smell tells you something has already spread through the flesh. Return it or bin it.

How to store watermelon in the fridge

• Whole: keep it in the coolest shaded spot in the house. In heatwave weather, the fridge is better if you have space. A cold melon also tastes sweeter.
• Before cutting: wash the rind under running water and rub it with your hands or a clean brush. The knife drags whatever is on the outside through the flesh.
• Half melon: cover the cut face with a plate or cling wrap and keep it in the fridge. Use within 3 to 4 days.
• Cubes: in a lidded box, 3 to 4 days. Don’t leave cut melon out for more than 2 hours in summer; it’s a favourite of stomach bugs.
• Freeze: cubes freeze well for sharbat, slush and smoothies. They go soft when thawed, so don’t expect crunch.

Be strict. The general rules in our fridge and stomach-infection guide apply to all cut fruit.

Why is my watermelon slimy?

Slime on the flesh or cut surface means bacteria or yeast have got going, and it usually comes with a sour or fizzy smell and a darker, glassy look. Throw the whole cut piece away. Don’t just trim the top layer.

Some things look alarming but are fine, and they’re worth knowing so you don’t throw away a perfectly good melon that simply grew a little unevenly in the field or was picked a few days early:

• Hollow heart: cracks or a hollow in the middle. It comes from uneven growth and is safe to eat.
• White streaks: harmless, but usually a sign it was picked a bit early.
• Grainy, sugary sparkle: often a very ripe melon, sometimes called “sugaring”. Eat it soon.

What watermelon does for you, honestly

Here’s the plain truth. Watermelon is mostly water, which is exactly why it’s so good in a Pakistani or Indian summer; a cup of cubes gives about 45 calories, some vitamin C and vitamin A, a little potassium, and lycopene, the red pigment also found in tomatoes. It’s a pleasant way to take in fluid.

What’s hype: it won’t flush your kidneys, melt fat or stand in for ORS if you’ve been losing fluid through loose motions or heat illness. For that, see heat exhaustion and heatstroke first aid. Whole cubes beat juice, because juicing loses the little fibre it has and makes it easy to drink three cups’ worth of sugar at once.

Watermelon drinks and a chaat

Tarbooz sharbat

3 cups deseeded cubes, juice of half a lemon, 6 mint leaves, a pinch of black salt. Blend 20 seconds and pour over ice without straining, so you keep the pulp and the fibre that comes with it; most ripe melons need no sugar.

Tarbooz chaat

2 cups cubes, a quarter cup of chopped cucumber, a small handful of roasted peanuts, a pinch of chaat masala and a squeeze of lemon. Toss just before serving, because salt draws out water fast.

Frozen slush

2 cups frozen cubes, 4 tbsp cold water, a few mint leaves; blend to a thick slush and eat with a spoon.

Good combos: watermelon with a few nuts or some paneer makes a steadier snack than watermelon alone. The old rule against water or milk straight after watermelon is covered, with verdicts, in our watermelon myths guide.

Seeds and rind: don’t bin them

• Black seeds: safe to swallow. They pass straight through. Dried and roasted, the kernels are one of the four seeds in char magaz. For children under 5, remove seeds to avoid choking.
• White rind: edible and mild, like cucumber. Peel off the hard green skin, cube the white part and cook it like lauki with cumin, turmeric and green chilli. It also makes a good sweet pickle.
• Green skin: compost it, or if you keep a kitchen garden, chop it small and bury it under the soil around your plants, where it breaks down in a couple of weeks in summer heat and feeds the worms instead of attracting flies to the bin outside.

Watermelon on skin

A cold slice rubbed on the face after a hot day feels lovely and does no harm, but it’s a cooling trick, not a skin tonic. If you use pulp as a 10-minute face mask, patch test on the inner arm first, keep it off broken skin, rinse with plain water and stop if it itches. Don’t add lemon if you’re going into the sun.

Myths and surprising facts

Myth: a bigger melon is a sweeter melon

The truth: weight for size matters, not size, since big melons are often picked early to catch the market.

Myth: swallowed seeds will grow in your stomach

The truth: seeds need soil, light and warmth. They pass through untouched. Children hear this as a joke and sometimes believe it.

Did you know?

• Botanically, a watermelon is a kind of berry.
• Watermelon’s wild ancestors come from Africa.
• Cold watermelon tastes sweeter than warm, even though the sugar is the same.

Watermelon questions people ask

More summer picking guides live in the Fruits and Vegetables section, including how to pick a sweet kharbooza.