Windowsill gardening is the smallest scale of gardening there is, and it is also one of the most rewarding: a sunny sill can grow fresh herbs all year, raise seedlings for the garden, and keep a few edible plants within arm's reach of the kitchen. It needs almost no space, no garden, and very little money — a few small pots, some potting mix and a bright window are enough to start. This guide covers how to choose a sill, what to grow on it, and how to keep windowsill plants alive through the year.
The first thing to check is light. A windowsill that faces south gets the most sun and suits basil, rosemary, thyme, chillies and most herbs. An east-facing sill gets gentle morning sun and suits most herbs and salad leaves. A west-facing sill gets strong afternoon sun, which is good but can overheat small pots. A north-facing sill gets little direct sun and suits mint, parsley, chives and leafy greens, but not sun-lovers such as basil. Watch your sill through a day and count the hours of direct sun before you choose what to grow. If the light is weak in winter, a small grow light can help — see our grow lights guide and the grow light calculator — but a grow light works best as a supplement for a bright sill, not as a replacement for daylight.
Pots, soil and drainage
Use small pots with drainage holes, and always put a saucer or tray underneath to protect the sill from water damage. Terracotta pots look good but dry out fast on a sunny sill, so check them often; plastic pots hold moisture better and are lighter. A long trough or window box uses the sill efficiently and suits salad leaves and mixed herbs, but make sure it fits the sill safely and cannot be knocked off. Do not use garden soil indoors: it is too heavy, it drains badly, and it can carry pests. Use a good potting mix, or make your own from our potting mix recipe. Fill pots to a couple of centimetres below the rim so water does not overflow when you water.
Turn pots regularly — a quarter turn every few days — so plants grow evenly instead of leaning towards the window. Keep pots away from radiators and heating vents, which dry them out fast, and away from cold draughts from badly sealed windows in winter. A sill above a radiator is one of the worst places for a plant: hot, dry air from below and cold glass above. If your only sill is above a radiator, put a tray of water nearby to raise humidity, or move the plants to a table near the window instead.
What to grow on a windowsill
Herbs are the best windowsill crop. Basil, parsley, chives, mint, thyme and coriander all grow well in small pots, and they are used fresh in cooking almost every day. Mint must have its own pot, because it spreads aggressively and will crowd out anything planted with it — see growing mint, growing basil, growing parsley and growing chives. Salad leaves, spinach and spring onions grow well in a trough and can be picked leaf by leaf — see growing lettuce and growing spinach. Chillies grow well in a sunny window and produce a useful crop from one plant, and microgreens — mustard, cress, radish and pea shoots sown thickly and cut young — are ready in one to two weeks and are ideal for a sill.
Seedlings are another classic windowsill job. Tomatoes, peppers, courgettes and flowers started indoors in spring get a head start before they go outside, but they need as much light as you can give them, and they go leggy — tall, pale and weak — if the light is poor. Sow them as late as you can, give them the brightest sill, turn them daily, and move them outside as soon as the weather allows, hardening them off first. Use the seed starting calculator to work out sowing dates, and the frost date calculator to check when it is safe to move plants outside. If you want a fuller herb setup, our indoor herb garden guide covers a dedicated indoor herb garden in detail.
Watering and feeding windowsill plants
Small pots dry out fast, especially on a sunny sill, so check the soil every day or two by pressing a finger into it: if the top couple of centimetres are dry, water; if they are still moist, wait. Water slowly until a little water runs into the saucer, then empty the saucer after half an hour so the pot is not standing in water. Overwatering is the most common way to kill a windowsill plant, because roots sitting in wet mix cannot breathe and begin to rot. Water in the morning when you can, and water the soil rather than the leaves. In winter, plants grow slowly and need far less water, so reduce watering and let the soil dry out more between waterings.
Feed lightly. A half-strength liquid feed every couple of weeks in spring and summer is enough for most herbs and salads, and herbs taste better when they are not overfed. Do not feed in winter, when plants are barely growing. Refresh the potting mix once a year for perennial herbs such as rosemary and thyme, or repot them into a slightly larger pot when they outgrow the old one. If a plant looks pale, leggy or unhappy, the cause is usually light or water, not food — fix those first before reaching for fertiliser.
Pests and problems indoors
Windowsill plants can still get pests, especially aphids and fungus gnats. Aphids cluster on soft new growth and can be picked off by hand or washed off with water. Fungus gnats are small black flies that appear when the soil is kept too wet; letting the surface dry out between waterings usually controls them, and removing dead leaves from the surface helps. Whitefly and spider mites can appear on plants that are stressed by heat or dry air. Check the undersides of leaves regularly, remove affected leaves, and improve air circulation by opening the window on mild days. Avoid sprays indoors, and use the pest identifier helper if you are unsure what you are looking at. If a plant is badly affected, it is often better to discard it than to risk spreading pests to your other plants. If you are unsure whether a plant is safe for children or pets in your household, check your local extension service for advice.
Windowsill gardening through the year
In spring, sow seeds and raise seedlings for the garden. In summer, herbs and salads grow fast, and the sill gives a daily harvest for the kitchen. In autumn, bring in tender herbs such as basil before the first frost, and sow a last round of salad leaves for winter picking. In winter, growth slows, and the sill is best used for hardy herbs such as parsley, chives and mint, and for microgreens, which grow fast even in low light. Keep a simple note of what grew well on your sill and what did not, because every window is different, and your own record is the best guide to what your sill can do. If you have more space than a sill, our apartment gardening and small space gardening guides cover the next steps up.
Common mistakes
The most common windowsill mistakes are overwatering, choosing sun-loving plants for a shady sill, using pots with no drainage, leaving pots above a hot radiator, and sowing seedlings too early so they go leggy before they can go outside. Another is planting mint in a shared pot, where it crowds everything else out. The fixes are simple: check the soil before watering, match the plant to the light you have, use pots with drainage and saucers, keep plants away from radiators, and sow at the right time. A windowsill garden should be small, useful and easy — if it feels like a chore, shrink it to the three or four plants you use most.
Frequently asked questions
What herbs grow best on a windowsill?
Basil, parsley, chives, mint, thyme and coriander all grow well on a bright sill. Basil needs the most sun and warmth; mint, parsley and chives cope with less light. Mint must have its own pot. Rosemary and thyme are perennial and can live on a sill for years if they get enough light.
Why are my windowsill seedlings tall and pale?
They are not getting enough light. Seedlings stretch towards the window when light is weak, producing long, weak stems. Give them the brightest sill you have, turn them daily, sow as late as you can, and move them outside as soon as the weather allows. A grow light can help in winter.
How often should I water windowsill plants?
Check the soil with a finger every day or two. If the top couple of centimetres are dry, water slowly until a little runs into the saucer, then empty the saucer. Small pots on a sunny sill may need water every day in summer and only once a week or less in winter. Never water on a fixed schedule without checking the soil.
Can I grow salad leaves on a windowsill?
Yes. Lettuce, spinach and mixed salad leaves grow well in a trough on a bright sill, and they can be picked leaf by leaf so one sowing gives weeks of harvest. Sow a little and often, keep the soil moist, and pick the outer leaves first so the plant keeps growing.
What is the best windowsill for growing?
A south-facing sill gets the most sun and suits the widest range of plants. East-facing is good for most herbs and salads, west-facing is sunny but can overheat small pots, and north-facing suits only shade-tolerant herbs and leafy greens. Whatever direction your window faces, match the plant to the light you have.