How to Not Kill Your Supermarket Herbs Days After Buying Them

This article originally appeared on VICE Italy.

So you bought yourself a cute little basil plant to up your pasta game and maybe even decorate your balcony. But days after your investment, you once again are left looking at a sad little brown stump.

I’ve done this over and over again, with all kinds of herbs. Each time I feel like they’re growing healthily green, and then suddenly, right on cue, they dry out or wilt or start breaking out in weird spots on their leaves.

“Most of my rules apply to all herbs. Except for basil – basil is in a league of its own,” says Luca De Marco, a chef and gardener who’s been studying, planting and cooking with aromatic plants for ten years. Together with his wife Francesca Lombardi, De Marco co-owns Aromaticus, a small franchise of two specialised stores and cafes in Rome, selling herbs and serving vegetarian meals.

“The rules that will help your herbs live a long and healthy life are: sun, wind and not too much water,” says De Marco. “You should water them a couple of times a week, at sunset or sunrise, except in July and August [when they need more].” Watering them earlier in the day or at night is better for these plants, because the water penetrates the soil and doesn’t evaporate or get too hot and boil the roots. 

Overall, De Marco says it’s better to give herbs too little water rather than too much, since they usually have thin roots which rot easily. You should make sure the soil can drain properly and that it’s not soaked before you water it again. If the plant’s leaves are turning yellow and then wilting, that’s a sign you’re overwatering them. 

De Marco also recommends potting different herbs together – “The more promiscuous, the better,” he says. “Each plant releases nutrients that the others need. Putting them together makes them work in synergy.” Once again, that’s only true for plants like rosemary, thyme, marjoram and sage, while basil and mint must be planted on their own.

“If I had to draw you a picture of where your herbs should be placed on your balcony, it would go like this: rosemary, thyme, sage and marjoram on the outer edge, basil towards the inside and sage in the middle.”

Basil is a versatile herb originally from tropical regions in central Africa and Southeast Asia. There are many different types – purple, white, Sicilian, lemon Basil – but the one most commonly sold in supermarkets is the sweet basil, which has medium-sized leaves. The plant grows only once a year, between April and October. “Unlike other aromatic plants, which may recover after the winter, basil always dies,” says De Marco. 

Basil likes sunlight, but not too much, and needs to be watered more than other plants, near-daily when it’s hot. An easy way to spot if your basil plant is thirsty is checking if its leaves are limp. As De Marco explains, if you buy a basil plant at the supermarket, you’re actually likely buying four or five small plants that have been potted together. The most important thing you can do to help them survive is to transfer them to a larger pot so they have room to unfurl their roots and grow.

You should also keep in mind that basil plants sold at the supermarket have been grown under special lights to develop quickly, without much care given to the health of their roots. That’s why it’s so hard to make them last even if you repot them. Instead of a fully-grown plant, you might want to consider buying seeds; that’s true for basil and for all other herbs.

To optimise the lifespan of your basil, De Marco says you shouldn’t pick the leaves at random, but rather start taking those at the top of the plant so that the bottom leaves, which are usually smaller, have time to grow. It’s also important to avoid ripping the leaves off – instead, clip them at the base together with their stem. If the plant starts to bloom, remove the flowers right away so you can delay the plant’s natural cycle.

Sage, another common aromatic plant, tends to develop white patches on its leaves if cared for incorrectly. “Under a microscope, the texture of sage leaves is quite odd, almost like suede,” says De Marco. And just like suede in a damp closet, mould can easily start growing on its surface. To avoid this scenario, you should put the plant in a well-ventilated spot and pot it in soil that never gets too wet, ideally with plants like thyme and rosemary. 

Rosemary is a bit of a gentle giant – it’s one of the strongest aromatic plants, capable of surviving harsh winters with little care, but it also protects the weaker plants around it, especially from direct sunlight. “Its smaller and thicker leaves are better at retaining water,” says De Marco. The plant is also perennial – it grows all year round – but it may temporarily lose its leaves in the cold season and regrow them again when temperatures warm up. 

“Rosemary gets pissed off if you don’t repot it regularly, if you water it too much or if it doesn’t get enough wind,” says De Marco. Usually, you should repot any plant if you realise it’s not growing in height. Rosemary can also start showing white mouldy spots, which usually means you need to move it to an area where it gets more wind. 

Plants like thyme and marjoram are pretty similar to rosemary, and they do great if potted together with it. Their thick narrow leaves allow them to grow even in direct sunlight and they don’t need much water – twice a week, three times in the summer. “Besides having small leaves, they’re also packed with essential oils, so they don’t dry out easily,” says De Marco.

Mint is a bit like basil – it’s better left alone. Since mint grows roots horizontally, it can get in the way of the other plants it shares a pot with. However, De Marco says the plant actually does very well if you put different mint varieties together.

“There are so many types of mint, and each one has very specific characteristics. Glacial mint is very balsamic, then there is the mojito mint, peppermint, Roman mint – which isn’t even a mint, it’s a catnip, but it tastes like mint.”

All in all, there are over 20 species of mint, plus hybrids.

Finally, if you’re concerned about buying plants at the supermarket because they might contain chemicals, you don’t need to worry.

“Plants are living organisms,” says De Marco. “Once you remove what’s bad for them, they quickly purify themselves. Also, since they come in small vases, the amount of chemicals present in them is relatively small.”

Within a month, they should go back to a fully natural state.