Too many people, basil is THE one herb to have in the kitchen garden. It is easy to see why basil is such a popular herb - it is generally easy to grow, very productive, and has delicious tasting leaves with many culinary uses, and to top it all off, has medicinal and culturally significant uses too.
There is a large number of culinary basil cultivars available, all from the same species plant: Ocimum basilicum. You may know about the typical sweet-savory spicy Italian style Genovese basil, often used for drying or making into Pesto, but there are also basil plants that have flavours like Cinnamon, Liquorice and Lemon. Some basil plants have tiny leaves (Fino Verde) and others can grow really large leaves (Lettuce Leaf basil). There’s basil that is bright green (Bush Basil) or purple-leaved (Red Rubin) and there are some basil plants grown for their beautiful decorative flowers (Cardinal) in addition to their uses in the kitchen.
You may also know of holy basil, or sacred basil, very often used in teas or as medicines. These, also known as Tulsi are a different species to culinary basil, they are either Ocimum sanctum (syn. Ocimum tenuiflorum), Ocimum gratissimum or Ocimum africanum.
These are not the only species in the Ocimum genus - Wikipedia lists over 60 distinct species of these aromatic herbs.Most culinary types of basil are grown as annuals even though some of the species may technically be classified as short-lived perennials in tropical climates.
It is possible to grow basil through the year – especially in a sunny windowsill inside the house (especially the small leaved bushy basil plants such as Minette Basil, Fino Verde Basil or Greek Bush Basil), or in a greenhouse or conservatory – each plant will complete its life cycle after flowering.
Tip: To encourage leaf production, pinch out the tops, to encourage side branching, and make sure to cut off flower stalks when they start to form.
Letting basil flower, however, ensures that you get seeds - and it feeds pollinators! Bees and bumblebees in particular, love basil flowers, and it is recommended as a plant to encourage bees to the garden.
When saving basil seeds, take note that because the culinary basil cultivars are all of the same species, Ocimum basilicum, and they are outbreeders (i.e. not commonly self-pollinating), cross-pollination between the different cultivars can occur easily if they are planted closely. This means hybridization may occur where new plants grown from cross-pollinated seed may not have the same characteristics as the parent plants.
The recommended isolation distances for saving pure seed of the different basil cultivars is near 500m, taking into consideration that bees often travel much farther and may carry pollen between two different cultivars.
SAVING BASIL SEEDS