Growing Herbs Indoors: Questions Answered

“Why do my supermarket herbs keep dying?” “Is it my fault?” “Where on the windowsill should they go?” If you’re asking one of these, the short answer is below, with a link to the full guide.

Why do my supermarket herbs keep dying so quickly?

Supermarket herbs are bred for looks rather than longevity, often packed tightly into tiny pots with restricted root space. They are pushed through the supply chain quickly and are expected to survive conditions that differ vastly from the stable environment they were raised in. The honest answer is that growing herbs indoors in the UK requires a completely different approach than general advice found on American blogs. Full details in our guide to Growing Herbs Indoors UK: Complete Windowsill Care Guide (/growing-herbs-indoors-uk-complete-windowsill-care-guide/).

Why is my basil turning black at the bottom?

Black leaves on basil usually indicate that the plant is either too cold or struggling to get enough light. Basil is a tropical plant that doesn’t tolerate frost and really doesn’t enjoy temperatures dropping below 15°C, which is common in unheated British rooms overnight. It also needs plenty of direct sunlight to thrive, which is hard to come by on a standard kitchen windowsill in winter. Full details in our guide to Basil Growing Conditions (/basil-growing-conditions/).

How often should I really be watering my herbs?

Watering on a strict schedule is the most common mistake UK flat dwellers make, as the plant’s needs change daily based on the weather and your heating. The problem isn’t usually too little water; it’s watering on a schedule instead of checking what the plant actually needs. You need to learn to read the compost and the plant rather than following a calendar. Full details in our guide to How Often to Water Basil and Parsley (/often-water-basil-parsley/).

Why is my rosemary dropping needles and going soft?

Rosemary and thyme are Mediterranean plants that evolved in dry, rocky conditions and hate having their roots constantly wet. In a British home with central heating, keeping the compost damp can easily lead to root rot, which causes the stems to go dark and soft near the soil. The label saying “once a week” is wrong for these plants in a centrally heated flat. Full details in our guide to How Often to Water Rosemary and Thyme (/often-water-rosemary-thyme/).

Can I grow herbs on a north-facing windowsill?

Many herbs, particularly basil, will struggle on a north-facing windowsill because they need direct sunlight to survive the British winter. The average UK kitchen windowsill gets significantly less direct sun than gardening websites assume, and basil is essentially asking for a Mediterranean summer. If you have a windowsill that doesn’t see much sun, you need to know which herbs actually tolerate low light. Full details in our guide to Herbs That Grow in Shade (/herbs-grow-shade/).

Why is my mint turning brown and dying in the pot?

Mint spreads through underground runners that circle back on themselves in a pot, filling the container with a dense root mass that exhausts the soil. You see the leaves yellowing and assume it is thirsty, so you water more, but the roots get wetter and the problem worsens. The fix is straightforward but requires understanding that your mint needs a bigger pot and regular division. Full details in our guide to Mint Plant Care (/mint-plant-care/).

Is it worth repotting supermarket herbs or should I just buy new ones?

Repotting supermarket herbs is the single most important step to stop them from dying within a week, as the roots are often wound tightly in a solid mat. Commercial producers sow seeds thickly to make the pot look lush, but this leaves the plant with nowhere for its roots to go. If you tip the plant out, you will see the roots are circling and strangling each other, which is not a healthy plant. Full details in our guide to How to Pot On Supermarket Herbs for Indoor Growing UK (/pot-supermarket-herbs-indoor-growing-uk/).

Where should I put my herbs on the windowsill for the best light?

Because of the UK’s northerly latitude, south-facing windows get the most direct sun, while north-facing windows get almost none. In winter, the sun is low and spends most of its time in the southern sky, leaving north-facing rooms dim for hours. This angle matters more than people realise, as it determines which herbs will actually survive on your windowsill. Full details in our guide to Best Windowsill Position for Herbs: Light Requirements UK (/best-windowsill-position-herbs-light-requirements-uk/).

Why do my herbs keep getting mould or damping off?

Mould or damping off often happens because the compost is staying too wet for too long, which is a common issue in UK homes with central heating. Standard peat-based compost holds moisture exceptionally well, which is brilliant for bedding plants in summer but can be a death sentence for herbs like thyme. When the roots sit in waterlogged compost, they suffocate and rot, leading to the collapse of the plant from the bottom up. Full details in our guide to Growing Thyme in Pots (/growing-thyme-pots/).

What is the best way to make my herbs bushier?

Pruning your herbs actually interrupts the plant’s natural urge to flower and set seed, redirecting energy into producing new stems and leaves. Most people are afraid of cutting a plant, but herbs are forgiving and bounce back from pruning in a way that most houseplants don’t. Regularly clipping basil or mint encourages continuous, harvestable foliage rather than one scrappy crop followed by a quick decline. Full details in our guide to How to Prune Basil and Mint for Bushier Growth (/prune-basil-mint-bushier-growth/).

Is it my fault that my herbs aren’t surviving?

It is almost certainly not your fault, as supermarket herbs are sold to be eaten, not grown, and are crammed into tiny pots with barely any soil. They are pushed under artificial light for a few days and expected to perform in a centrally heated flat that bears no resemblance to a greenhouse. There are specific, fixable reasons indoor herbs fail in UK homes, and once you know what they are, you can actually do something about it. Full details in our guide to Common Mistakes When Growing Herbs Indoors UK (/common-mistakes-when-growing-herbs-indoors-uk/).

Why is my parsley turning yellow?

Parsley is hardier than basil, but it still needs regular moisture to produce the leaf growth you want to harvest. The problem is often that the soil is drying out too quickly due to central heating, causing the leaves to turn yellow and the plant to struggle. While it forgives the odd missed watering better than basil does, consistent moisture is key to keeping it healthy. Full details in our guide to How Often to Water Basil and Parsley (/often-water-basil-parsley/).

If your specific question isn’t covered here, the full guide has the detail you need. Start with our Growing Herbs Indoors UK: Complete Windowsill Care Guide.