Sweet Genovese
The pesto basil, and the one worth the extra fuss, but only if you have a greenhouse or a genuinely sunny south facing sill.
This is the basil people picture: broad, soft, cupped green leaves with the sweet clove and aniseed smell that makes pesto worth making. It is also the basil that suffers most in Irish conditions, because those big thin leaves are exactly what cold and damp damage first. Grown in a greenhouse or on a bright warm windowsill it is generous and easy. Grown in an open Irish border it is a slow, mildewed disappointment, and no amount of care changes that.
Quick facts
- Botanical name
- Ocimum basilicum
- Type
- Open pollinated
- Category
- Sweet basil, large leaved
- Difficulty
- Challenging
- Hardiness
- Tender, no frost tolerance
- In Ireland
- Needs a greenhouse or tunnel
- Germination
- 5 to 14 days at 18 to 25C
- Sowing depth
- 5mm
- Spacing
- 20cm apart, 25cm between rows
- Height
- 45cm
- Position
- Full sun
- Containers
- Grows well in pots
- Sowing to harvest
- 8 to 12 weeks
- Harvest
- June to September
Sowing and harvest calendar for Sweet Genovese
Months shaded below are the reliable windows for Irish conditions.
Where to buy Sweet Genovese basil seeds in Ireland
Irish suppliers that stock this, so postage stays domestic and seed arrives in time to sow. These are plain links, not paid placements.
Garden centres and mixed retailers
- Mr Middleton Irish Six basil varieties, the widest choice here Mail order arm of a long established Mary Street shop, carries the familiar named varieties the organic specialists skip. Visit Mr Middleton , Co. Dublin
- Johnstown Garden Centre Irish Four basil lines including organic Third generation family business near Naas with the widest branded range, though popular varieties sell out by midsummer. Visit Johnstown Garden Centre , Co. Kildare
Why it suits Ireland
It does not, particularly, and that is the honest answer. Sweet Genovese is a hot climate plant grown here in spite of the climate rather than because of it. What makes it worth including is that under glass, in a pot on a warm sill, or in a polytunnel, it grows perfectly well and there is no substitute for it in the kitchen.
The Irish adjustment is where you put it, not how you grow it. Given 18C and above, good light and compost that dries slightly between waterings, this is an easy plant. Given an Irish June night at 8C and rain on the leaves, it blackens.
Growing notes
Sow from mid-March to early June at 18 to 25C. Prick out into 9cm pots at the first true leaves, or grow on as clumps of two or three seedlings per pot, which gives a fuller plant sooner.
Plant into a greenhouse border or a 20cm pot from late May, spacing 20cm apart. It reaches around 45cm and wants room for air to move around it, because crowded large leaved basil in a humid tunnel is where downy mildew starts.
Start cutting when the plant is about 15cm tall, taking whole stems back to just above a leaf pair rather than picking individual leaves. Two shoots come from every cut, so a plant harvested this way from the start is bushy and productive, while one picked leaf by leaf grows into a bare stem with a tuft on top.
Pinch out flower spikes on sight. Genovese types run to flower readily once they reach full size, and the flavour changes noticeably once they do.
Water in the morning only, at the compost rather than over the leaves, and only when the surface has dried. Overwatering kills more Genovese basil in Ireland than cold does.
Common questions
How many plants do I need to make pesto?
More than most people sow. A decent batch of pesto for four takes about 50g of leaves, which is a good handful of stems, and that is close to everything a single well grown plant will give you in one cut. Six to eight plants in a greenhouse border, cut hard and allowed to regrow, will keep a household in pesto through August and September. Sowing three modules and hoping is the usual mistake.
Is Genovese different from ordinary sweet basil?
Genovese is a selection within sweet basil, chosen for large cupped leaves and a strong sweet aroma without the minty note some sweet basils carry. Packets labelled simply Sweet Basil are very close and will do the same job. Genovese types tend to have slightly bigger leaves, which is convenient when you are picking by weight for pesto.
Will it grow in a greenhouse alongside tomatoes?
Yes, and it is a sensible use of the space, since both want the same warmth and the same well drained compost. Give the basil a spot at the front where it gets light rather than tucking it under the tomato canopy, and be careful not to water it as often as the tomatoes, because tomatoes want far more water than basil does. The old claim that basil repels whitefly from tomatoes is not reliable, though French marigolds genuinely do help.
More basil to consider
Greek Basil
Open pollinated / Bush basil, small leaved
The basil to start with if you have failed with basil before. Small leaves, dense growth, and far more tolerant of cool damp air.
Growing notes and stockistsDark Opal
Open pollinated / Purple leaved sweet basil
Grown for the colour more than the harvest. Slower and fussier than green basil, so give it the warmest brightest spot you have.
Growing notes and stockistsThai Basil
Open pollinated / Thai or anise basil
Worth growing for the aniseed flavour that holds up in a hot wok, but it is greenhouse only in Ireland and slow to start.
Growing notes and stockists