Basil

BeginnerRepeatedly through the seasonPlanted as transplant

Ocimum basilicum

A heat-loving annual herb that gives back more the more you pick it. Keep it warm, pinch the tips often so it bushes out instead of flowering, and one row of plants will carry a summer of pesto, salads and cold drinks.

Light

Full sun (6+ hours)

Full sun and warmth; basil grown in shade is thin, pale and short on flavour.

Water

Moderate

Keep the soil evenly moist and water in the morning so the leaves dry quickly.

Soil & substrate

Any well-drained soil

Ordinary garden soil that drains well, with a little compost worked in.

Feeding

Moderate feeder

Feed lightly every couple of weeks; heavy feeding gives big leaves with weak flavour.

Training

Prune

Pinch the growing tips out regularly: it makes the plant bush out, and it delays the flowering that ends the leaf harvest.

Harvest signs

Start picking once the plant has six to eight leaves, and keep cutting stems every week or two; the flavour is best just before the flowers open.

Life of the plant

Timing shifts with your frost dates — never fixed calendar days

1Germination1–2 weeks after sowing

Seeds need real warmth to come up: about ten days somewhere around 24 C.

2Seedling10–28 days after the previous stage

Seedlings need bright light and warmth; do not rush them outside while nights are still cold.

3Vegetativefrom transplanting to 30 days after

The plant settles in and bushes out; give it the first pinch once it has six to eight leaves.

4Cut and come againfrom the previous stage to 90 days after

Cut stems every week or two and the plant keeps replacing them right through summer.

5Flowering60–90 days after the previous stage

If flower spikes are left on, leaf growth stops and the flavour turns bitter; let one plant flower for the bees if you like.

Varieties

Generic

What to watch for

What each one looks like, so you know it when you see it

Slugs and snailsPestHigh susceptibility

Stages affected: Germination · Seedling · Vegetative · Cut and come again

Soft-bodied molluscs that feed at night and in wet weather, rasping holes in leaves. Seedlings and low soft foliage are the most at risk, and a single night can take out a row of young plants.

Visual signs: Ragged holes with smooth edges chewed through the middle of leaves rather than at the margins · Silvery dried slime trails on leaves soil and pots, which is the deciding feature · Damage appears overnight and stops in dry sunny spells · Seedlings grazed off at soil level · Slugs or snails found under boards pots and mulch during the day
Damage pattern: Worst after rain irrigation and in humid shaded beds · Feeds at night; plants look untouched by day · Concentrated on low soft leaves near the soil

Basil downy mildewWater mould (oomycete)High susceptibility

Stages affected: Seedling · Vegetative · Cut and come again

A water mould and the disease most likely to end a basil crop. It arrives on the wind or on infected transplants and moves up the plant from the lower leaves, worst in the humid weather of late summer.

Visual signs: Pale yellow areas on the upper surface of the leaf often bounded by the leaf veins · Velvety grey to purple fuzz on the underside directly beneath the yellow patch, which is the deciding feature · Symptoms start on the lower leaves and move upward · Whole leaves yellow then brown, and black specks appear on older infected tissue · Plants look worst after warm humid nights
Damage pattern: Lower leaves first, moving up the plant · Severe in warm humid weather and at its worst in late summer · Arrives on infected seed transplants or fresh leaves, and spores travel long distances on moist air

AphidsPestMedium susceptibility

Stages affected: Seedling · Vegetative · Cut and come again

Small soft-bodied sap-sucking insects that cluster on the softest new growth. They reproduce extremely fast in warm weather and are the main insect vector of plant viruses in the garden.

Visual signs: Clusters of small pear-shaped insects on shoot tips buds and leaf undersides · A pair of short tubes (cornicles) projecting back from the rear end, which is the deciding feature · Green yellow brown red or black depending on species, wingless or winged · Curled twisted or yellowing new leaves and stunted shoots · Sticky honeydew on the leaves below, often turning black with sooty mould · White cast skins left on leaves and easily mistaken for live insects · Ants running up and down the stems
Damage pattern: Concentrated on the newest softest growth and worst on heavily fed plants · Honeydew and sooty mould appear below the colony rather than at it · Virus symptoms such as mottling yellowing and distorted growth may follow long after the aphids have gone

Japanese beetlePestMedium susceptibility

Stages affected: Vegetative · Flowering · Cut and come again

A metallic beetle about 10 mm long that feeds in groups on leaves and flowers through midsummer. The adults do the damage you see above ground while the grubs feed unseen on grass roots below.

Visual signs: Adult about 10 mm long with a metallic green head and thorax and copper-brown wing covers · Small white tufts of hair along each side of the body below the wing covers · Several beetles clustered on one leaf and most active on warm sunny afternoons · Cream-colored C-shaped grubs with brown heads in the top 50 mm of soil under grass
Damage pattern: Leaf tissue chewed away between the veins so only a lace-like skeleton is left · Damage begins at the top of the plant and on leaves in full sun · Ragged holes in flower petals and on ripening fruit · Patches of lawn that brown and lift easily where grub feeding has cut the roots

Fusarium wilt of basilFungal diseaseMedium susceptibility

Stages affected: Vegetative · Flowering · Cut and come again

A soil-borne fungus that blocks the water-conducting tissue of sweet basil. It is seed-borne as well as soil-borne, survives in soil for years, and there is no cure once a plant is infected.

Visual signs: Sudden wilting of one side or one shoot while the rest of the plant looks well · Leaves yellow then brown and drop, often on a single stem first · Brown streaks in the stem when a stem is cut lengthwise, which is the deciding feature · Stunted twisted growth on young plants · Plants collapse over days rather than recovering overnight
Damage pattern: Scattered individual plants rather than a whole bed at once · Worse in warm soil and in beds where basil has grown before · Arrives on infected seed or in infested soil and persists for eight to twelve years

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A free account turns this page into a plan for your garden: these stages dated against your own frost, each task as it comes due, what to do about each pest, and the full depth behind every section.

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Basil

BeginnerRepeatedly through the seasonPlanted as transplant

Ocimum basilicum

Light

Full sun (6+ hours)

Full sun and warmth; basil grown in shade is thin, pale and short on flavour.

Water

Moderate

Keep the soil evenly moist and water in the morning so the leaves dry quickly.

Soil & substrate

Any well-drained soil

Ordinary garden soil that drains well, with a little compost worked in.

Feeding

Moderate feeder

Feed lightly every couple of weeks; heavy feeding gives big leaves with weak flavour.

Training

Prune

Pinch the growing tips out regularly: it makes the plant bush out, and it delays the flowering that ends the leaf harvest.

Harvest signs

Start picking once the plant has six to eight leaves, and keep cutting stems every week or two; the flavour is best just before the flowers open.

Life of the plant

Timing shifts with your frost dates — never fixed calendar days

1Germination1–2 weeks after sowing

Seeds need real warmth to come up: about ten days somewhere around 24 C.

2Seedling10–28 days after the previous stage

Seedlings need bright light and warmth; do not rush them outside while nights are still cold.

3Vegetativefrom transplanting to 30 days after

The plant settles in and bushes out; give it the first pinch once it has six to eight leaves.

4Cut and come againfrom the previous stage to 90 days after

Cut stems every week or two and the plant keeps replacing them right through summer.

5Flowering60–90 days after the previous stage

If flower spikes are left on, leaf growth stops and the flavour turns bitter; let one plant flower for the bees if you like.

Varieties

Generic

What to watch for

What each one looks like, so you know it when you see it

Slugs and snailsPestHigh susceptibility

Stages affected: Germination · Seedling · Vegetative · Cut and come again

Soft-bodied molluscs that feed at night and in wet weather, rasping holes in leaves. Seedlings and low soft foliage are the most at risk, and a single night can take out a row of young plants.

Visual signs: Ragged holes with smooth edges chewed through the middle of leaves rather than at the margins · Silvery dried slime trails on leaves soil and pots, which is the deciding feature · Damage appears overnight and stops in dry sunny spells · Seedlings grazed off at soil level · Slugs or snails found under boards pots and mulch during the day
Damage pattern: Worst after rain irrigation and in humid shaded beds · Feeds at night; plants look untouched by day · Concentrated on low soft leaves near the soil

Basil downy mildewWater mould (oomycete)High susceptibility

Stages affected: Seedling · Vegetative · Cut and come again

Visual signs: Pale yellow areas on the upper surface of the leaf often bounded by the leaf veins · Velvety grey to purple fuzz on the underside directly beneath the yellow patch, which is the deciding feature · Symptoms start on the lower leaves and move upward · Whole leaves yellow then brown, and black specks appear on older infected tissue · Plants look worst after warm humid nights
Damage pattern: Lower leaves first, moving up the plant · Severe in warm humid weather and at its worst in late summer · Arrives on infected seed transplants or fresh leaves, and spores travel long distances on moist air

AphidsPestMedium susceptibility

Stages affected: Seedling · Vegetative · Cut and come again

Small soft-bodied sap-sucking insects that cluster on the softest new growth. They reproduce extremely fast in warm weather and are the main insect vector of plant viruses in the garden.

Visual signs: Clusters of small pear-shaped insects on shoot tips buds and leaf undersides · A pair of short tubes (cornicles) projecting back from the rear end, which is the deciding feature · Green yellow brown red or black depending on species, wingless or winged · Curled twisted or yellowing new leaves and stunted shoots · Sticky honeydew on the leaves below, often turning black with sooty mould · White cast skins left on leaves and easily mistaken for live insects · Ants running up and down the stems
Damage pattern: Concentrated on the newest softest growth and worst on heavily fed plants · Honeydew and sooty mould appear below the colony rather than at it · Virus symptoms such as mottling yellowing and distorted growth may follow long after the aphids have gone

Japanese beetlePestMedium susceptibility

Stages affected: Vegetative · Flowering · Cut and come again

A metallic beetle about 10 mm long that feeds in groups on leaves and flowers through midsummer. The adults do the damage you see above ground while the grubs feed unseen on grass roots below.

Visual signs: Adult about 10 mm long with a metallic green head and thorax and copper-brown wing covers · Small white tufts of hair along each side of the body below the wing covers · Several beetles clustered on one leaf and most active on warm sunny afternoons · Cream-colored C-shaped grubs with brown heads in the top 50 mm of soil under grass
Damage pattern: Leaf tissue chewed away between the veins so only a lace-like skeleton is left · Damage begins at the top of the plant and on leaves in full sun · Ragged holes in flower petals and on ripening fruit · Patches of lawn that brown and lift easily where grub feeding has cut the roots

Fusarium wilt of basilFungal diseaseMedium susceptibility

Stages affected: Vegetative · Flowering · Cut and come again

A soil-borne fungus that blocks the water-conducting tissue of sweet basil. It is seed-borne as well as soil-borne, survives in soil for years, and there is no cure once a plant is infected.

Visual signs: Sudden wilting of one side or one shoot while the rest of the plant looks well · Leaves yellow then brown and drop, often on a single stem first · Brown streaks in the stem when a stem is cut lengthwise, which is the deciding feature · Stunted twisted growth on young plants · Plants collapse over days rather than recovering overnight
Damage pattern: Scattered individual plants rather than a whole bed at once · Worse in warm soil and in beds where basil has grown before · Arrives on infected seed or in infested soil and persists for eight to twelve years

Grow it with us

A free account turns this page into a plan for your garden: these stages dated against your own frost, each task as it comes due, what to do about each pest, and the full depth behind every section.

Create a free account Open it in your toolkit