If you’ve watched too many pots of supermarket basil wither and die when you’ve barely picked a few leaves, take heart. A viral hack promises to transform that puny pot into a thriving, bushy plant that can last for months.

And those bunches of herbs that go slimy in their packets before you’ve used them up? With the right treatment, they can stay fresh far longer than you might expect.

Love them or loathe them, supermarket options are the most convenient and accessible form of herbs for most of us. They’re not perfect, says Mark Diacono, a grower and author of Herb: A Cook’s Companion.

“Supermarket herbs tend to be grown fast and unsustainably using heat and a lot of feed and water,” he says. “And some varieties of coriander and basil are chosen more for reliability than flavour.”

But buying “living” supermarket herbs in pots can still be a good thing. “It’s the most easily accessible way to grow herbs,” he says.

How to produce bushy basil from a supermarket pot

Interior designer Leanne Kilroy has racked up more than 27 million views on her Instagram account @goodboneslondon by demonstrating how to turn small, gangly pots of basil into large, flourishing plants.

The roots of supermarket basil tend to be cramped and tangled in small plastic pots, Kilroy explains, and when left alone they rarely last more than a week or two. But by replanting the herb into much bigger pots and giving them a little TLC, they can grow into healthy and productive plants that last for months.

Kilroy suggests transplanting the basil into terracotta pots, which allow for good aeration and drainage, filled with compost. If you like, you can carefully divide the root ball into two or three plants and pot them separately. Once replanted, give the basil a final generous drink from the top. Then place the pot in a saucer or shallow bowl of water, and keep it topped up at all times – don’t water from above. Choose a sunny spot indoors for it to live.

“Snipping the stems, rather than plucking leaves, once the basil is actively growing will create a healthier, bushier plant,” Kilroy says, adding that any flowers must be trimmed immediately.

With the right conditions and a little luck, you could end up with an astonishingly long supply of basil. “Last year, mine lasted nine or 10 months and would still be hobbling on if I hadn’t made pesto with it,” she says. She has also had success doing this with parsley.

How to store supermarket herbs to help them last longer

Bunches of herbs sold in packets can last for days if stored correctly, says Victoria Green, UK supermarket Waitrose’s salads and veg expert. Keep most cut herbs in their original packaging in the fridge’s salad drawer, where stable temperatures and gentle humidity help preserve freshness. “Any temperature abuse before refrigerating can cause issues,” she warns, but an unopened bag might last up to seven days unopened.

Once open, roll the top of the bag over to make it as airtight as possible. Those elastic bands around the stalks? Keep them on: “It means you can chop from the top of the bunch (or the bottom if you want stalks), then easily put the remaining product back in the bag.”

The exception is basil. “It thrives when kept in a cool, dry place, not in the fridge,” says Green. Leave it in its original packaging, away from sunlight which will make it “sweat”. In the cupboard is best.

If you buy herbs without packaging, stand them in a jar of water, cover with a plastic bag secured with an elastic band, and store them in the fridge door, advises Catherine Phipps, author of Leaf.

“If keeping them upright is not possible, soak a piece of kitchen towel in water, wrap it around the stems and store flat in a bag or preferably an airtight container,” she says.

Depending on freshness at the time of purchase (Phipps suggests trimming the ends of the stalks if they’re dry), herbs can last up to two weeks when stored this way.

How to make supermarket herbs go further in food and drinks

Herbs can elevate far more dishes than most people realise, says Csabi Nagy, executive chef at London’s Petersham Nurseries, so it’s easy to use them up.

With eggs

Parsley, chives, basil, dill, marjoram and sage especially are natural companions to eggs. Fold them through scrambled eggs, or scatter over the top of fried or poached. Try frying eggs in butter with a few sage leaves. “It’s a delicious combination,” says Nagy.

Or make a quick herb salsa: finely chop a mixture of soft herbs, stir through some olive oil and a pinch of lemon zest, then spoon this over eggs, or with meat, chicken or fish.

In salads

Herbs are often overlooked as salad ingredients but offer great potential. “I personally like dill or fennel [fronds], basil and marjoram, as they give a bit of freshness and bring their own character,” says Nagy.

It works best to combine them with more robust lettuce leaves, and keep the dressing simple, too, so the herbs can shine. “A basic lemon dressing made with 70 per cent olive oil and 30 per cent lemon juice goes a long way,” he says.

In drinks

Mint commonly features but others are delicious, too. “We use rosemary for a bit of sophistication,” says Nagy, especially when infused into clear spirits. Tarragon pairs beautifully with gin or some whiskies, while thyme works well in citrusy cocktails. Basil adds a little kick and complements both vodka and gin.

“The best way to bring out the flavour is to infuse them or crush them directly into the drink,” Nagy says. Phipps suggests scalding your chosen herb sprig in boiling water, drying it thoroughly, and leaving it to infuse in the alcohol indefinitely.

In yoghurt and butter

Mix chopped tender herbs and crushed garlic into Greek yoghurt for an easy dip or sauce to serve with grilled meat or chicken, or instead of mayonnaise in sandwiches.

Phipps suggests mixing finely chopped herbs with softened butter and other aromatics like lemon zest, garlic or chilli flakes. “Simply pile onto a piece of cling film or baking paper, shape into a log, roll up tightly, store in the freezer and cut slices as necessary.”

Use the stems

The thin, tender stems of soft herbs like parsley, coriander and basil have bags of flavour and can be used just like the leaves. But slightly woody or stringy stalks don’t have to be wasted. “We use the stems in stocks, chicken or beef sauces and vegetable stocks,” Nagy says.

Rosemary and thyme stalks can also be added to the grill to deliver a gentle hint of smoky herb flavour, he suggests.

Longer-term solutions to stretch out supermarket herbs

If you know you’re not going to get through all your herbs before they turn, preserve them.

Freeze

Phipps suggests finely chopping herbs, packing them into ice-cube trays and topping them with water, olive oil or melted butter. “Once frozen, you can then turn them out into bags or boxes for easy storage,” she says.

Stalks can be chopped very finely and stored in a tub in the freezer for a quick flavour boost for everything from eggs to soups.

Dry

Hard herbs such as rosemary, thyme and sage can be tied in bunches and hung upside down for a few days to dry. Strip the leaves from the stems and store in jars.

Salt

Mix 50g sea salt with about a tablespoon of dried herbs. “They can all be blitzed together to a fine powder, so the salt has a slightly grittier texture than icing sugar or bashed together using a pestle and mortar for a coarser texture,” says Phipps.

The Telegraph, London