Genovese Basil
Ocimum basilicum
The pesto basil: large soft cupped leaves, sweet and clove-scented, and highly mildew-prone.

What makes it the pesto basil
Genovese has large, soft, slightly cupped leaves with a sweet clove-and-anise aroma and very little of the harshness some basils carry. It purées smoothly rather than stringily, which is exactly what pesto needs. Sweet basil and Genovese are often sold interchangeably, but true Genovese strains are milder and less minty.
Downy mildew hits it hardest
Genovese and other large-leaved sweet basils are the most susceptible types to basil downy mildew, which arrives on wind-blown spores most summers, yellows the leaves between the veins with grey-purple fuzz underneath, and can destroy a planting in a fortnight. Resistant Genovese-type varieties now exist - Prospera, Amazel, Rutgers Devotion, Rutgers Obsession - and are genuinely worth seeking out over generic seed.
Warmth, and never cold
Below 50F the leaves blacken. Set out well after last frost, once nights hold above 55F. Cold-damaged basil rarely recovers properly.
Pinch relentlessly
Cut the top third back to just above a leaf pair every couple of weeks. This prevents flowering - which turns the flavour harsh - and forces branching. Never strip individual leaves from the bottom; that gives you a bare stalk with a tuft on top.
Do not overfeed
Rich soil is good, heavy nitrogen is not. Excess nitrogen gives big soft leaves with visibly diluted essential oil, which is why lush-looking commercial basil often tastes of very little.
Water at the base, in the morning
Steady moisture, delivered to the soil, early enough that the foliage dries. Wet leaves overnight is what mildew wants.
Succession sowing
Sow a fresh batch every four to six weeks. Between mildew and plants tiring, having young stock coming along is the practical answer. Cuttings root in water in about a week.
Storage and preserving
Never refrigerate - cold blackens it. Stand cut stems in water on the counter. It dries badly, losing most of its aroma. Freeze it instead, chopped in oil in ice cube trays, or as finished pesto, which freezes excellently.
- Days to harvest
- 60-75
- Spacing
- 10-12 in
- Sun
- Full
- pH
- 6.0-7.0
- Soil temp
- 65F+
- Leaf
- Large, cupped, soft
- Mildew
- Highly susceptible
- Use
- Pesto, caprese