Check drainage before you water
The first task is not watering but making sure the water can get out. In terracotta or plastic pots, the hole at the bottom becomes blocked with roots, compacted soil or a badly placed layer of gravel. Lift the pot and look: if the saucer holds standing water for more than a day, there is a problem that autumn rain will make worse. On the coast, where rainfall can arrive suddenly, a pot without effective drainage is a trap for the roots of rosemary, thyme or sage.
The practical test is simple: water once and see how long it takes for water to come out at the bottom. If none comes out, or it comes out cloudy and slow, repot or loosen the compost with a thick stick before the next rain. Inland, where nights are colder and evaporation lower, also check that the pot is not pressed against a wall that holds moisture.
- Use a raised saucer or pot feet to lift the base off the ground and help drainage.
- Do not add a thick layer of gravel at the bottom: it can hinder drainage if the compost is fine.
Adjust watering to the season, not the calendar
The most common autumn mistake is keeping the summer watering routine. Mediterranean herbs tolerate drought better than waterlogging, and with milder temperatures the compost dries more slowly. Before watering, put a finger into the soil or use a wooden stick: if it comes out damp several centimetres down, wait. On the coast, one deep watering every few days is usually enough; inland, with cold nights, the interval lengthens.
It is worth distinguishing between small pots, which dry quickly, and large ones, which hold moisture longer. A thyme in a 20-centimetre pot may need more frequent watering than a rosemary in a 40-centimetre one. Watch the leaves too: an overwatered herb yellows from the bottom and loses aroma; with too little water, the leaves become leathery and curl inwards.
- Water in the morning so that surplus water evaporates during the day.
- Avoid wetting the foliage if nights are cool: it encourages fungus on dense leaves.
Renew the compost and feed with judgement
After summer, many herbs have used up their compost and roots are showing through the drainage holes. Autumn is a good time to renew the top layer or repot into a slightly larger container, without jumping to disproportionate sizes that hold too much water. A mineral compost, with coarse sand and well-rotted organic matter, works better than a compact, peaty one. The test is that water passes through quickly and that a handful does not form a hard ball when squeezed.
With feeding, be cautious. Too much nitrogen in autumn produces soft growth that cold can damage. If the plant has grown well, renewing the top layer of compost and adding a small amount of mature compost is enough. In indoor pots with early heating, the dry air may call for light, more frequent watering, but never waterlogging.
- Do not repot into a much larger container: the surplus compost holds unnecessary moisture.
- Remove dead leaves from the surface so they do not mat down and rot.
Light pruning and airing the foliage
In autumn, avoid severe pruning of evergreen herbs such as rosemary or sage. Hard pruning before the cold leaves the plant exposed and without reserves. What is appropriate is a clean-up: remove faded flowers, dry stems and crossing branches that stop air circulating. Indoors, where morning humidity can be high, that airing reduces the risk of fungal problems.
A practical example: a potted lavender with a very dense centre and drooping outer branches usually indicates lack of light and excess water. Rather than cutting it to the ground, thin the centre and let the air circulate. If the plant is very woody, renew pruning in spring, not now. Patience in autumn prevents losses.
- Disinfect scissors between plants so you do not carry problems from one pot to another.
- Do not cut more than a third of the foliage in a single session.
Protect from wind and cold according to location
On the coast, wind can be more limiting than cold. Pots on exposed terraces suffer rapid drying of foliage and can blow over. Group pots together or place a light barrier that breaks the wind without creating a damp, closed corner. Inland, where minimum temperatures can drop lower, move pots away from places where cold collects, such as shaded inner courtyards, and closer to a wall that holds warmth.
The temptation to cover with plastic is common, but it can create condensation and smother the plant. If you protect, use breathable materials and remove the covering during the day. Check weight too: a large pot soaked by rain can topple in a gust. Secure the base before storms arrive.
- Do not cover the plant permanently: ventilation matters as much as protection.
- On tall pots, check that the ballast or base is stable before the rains.
Common mistakes and practical observation
A common mistake is treating all herbs alike. Rosemary and thyme prefer drier, more mineral compost; basil, by contrast, is more demanding of water and does not tolerate cold. In autumn, basil usually declines on the coast, and it is better to renew it in spring than to force it. Another mistake is feeding heavily to compensate for yellowing: often that yellowing indicates too much water, not a lack of nutrients.
Daily observation solves more than any recipe. Touch the compost, look at the base of the stem, lift the pot. Practical experience shows that potted herbs last longer when you water less and observe more. This autumn, prioritise drainage, adjust watering and avoid hard pruning; the plant will respond in spring with firm growth and intense aroma.
- Keep a simple record of watering and rainfall so you do not repeat routines that do not work.
- If a plant shows signs of suffocation, repot into a more mineral compost before it gets worse.