Growing herbs on a windowsill that last past week two

Nearly everyone has bought a living herb from the supermarket, kept it on the windowsill, and watched it collapse within two weeks. It is easy to take that as proof you cannot grow herbs. It is really proof of how those pots are grown and sold, and once you understand that, keeping herbs alive for months is straightforward.

Why supermarket pots die so fast

That pot of basil is not one plant. It is dozens of seedlings sown thickly and forced along under ideal nursery conditions to look lush on the shelf. Crammed together, they compete for light, water, and root space, and they were never meant to last. They were meant to be used within days.

Two moves turn that doomed pot into a plant that keeps growing:

• Split it. Tip the plant out, and gently tease the mass of seedlings into two or three clumps. Repot each clump into its own pot with fresh potting mix. You now have fewer plants with room to grow, instead of fifty strangling each other.
• Repot into something bigger. The nursery pot is tiny and dries out in hours. A larger pot holds more soil, more moisture, and more room for roots, which evens out the swings that kill them.

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Light is the whole game indoors

Herbs are sun plants. The number one reason they struggle indoors is too little light. A windowsill that gets several hours of direct sun, ideally one facing the midday sun, is what they want. A dim north-facing sill will keep them limping along at best.

Signs of too little light are the same across most herbs: pale, stretched stems with long gaps between leaves, leaning hard toward the glass, and thin, sparse growth. If that is happening, move them to your brightest window before you change anything else. Turn the pots every few days so they grow evenly rather than reaching one way.

Three that reliably work on a sill

Basil is the classic windowsill herb and the one most often killed. It wants warmth, plenty of light, and steady moisture without sitting wet. Pinch out the growing tips regularly and it bushes out instead of bolting straight to flower.

Mint is nearly impossible to kill, which is both its strength and its warning. It grows in poorer light than most herbs and tolerates uneven watering. The catch is that it spreads aggressively, so keep it in its own pot rather than sharing.

Parsley is slower to start but tough and long-lived once going. It copes with a little less sun than basil and keeps producing through cooler months, which makes it one of the most reliable herbs to keep on a kitchen sill year round.

Harvesting so they keep going

The way you pick decides how long a herb lasts. Harvest little and often from the top, pinching or cutting just above a pair of leaves. The plant responds by branching into two new stems, so regular picking makes it fuller, not sparser.

Never strip a plant bare in one go, and do not let basil or similar herbs run to flower if you want to keep harvesting leaves, because once they flower the leaf flavour fades and growth slows. Treat a windowsill herb as something you prune constantly, and it will keep giving for months rather than weeks.