Germination time for basil – The seeds will usually germinate in about 5-10 days. Basil seeds need warm soil to germinate, so be sure to use a seedling heat mat to speed things up. getbusygardening
Paper Towel Seed Germination

Basil seeds take between eight and 14 days to germinate and emerge from the soil. After germination, look for the first set of true leaves two to three weeks later. Then, two to three weeks after the first set of true leaves emerge, basil plants should be about 6 inches tall and ready to plant out in the garden. sfgate

To get a head start, start the seeds indoors 6 weeks before the last spring frost. (See local frost dates.) To plant outside, wait until the soil is at least 50 degrees—preferably around 70ºF for best growth. Don't rush basil.

If you want a large basil plant, refrain from pinching the tip when the plant is 6 inches tall as most gardeners advise. Allow the plant to grow fast and furious until it is between 12-15 inches tall. Pinch not just the apical bud and the first pair of leaves as you would normally do. Remove around 2 inches of the stem tip. This promotes branching from lower nodes. naturallivingideas

Basil Companion Planting
Basil companion planting will help asparagus, beans, beets, cabbage, chili and bell peppers, eggplant, marigolds, oregano, potatoes and tomatoes.

Tomatoes benefit from basil companion planting. Growing tomatoes and basil near each other is said to make each crop taste better. One expert did suggest that the only benefit of planting basil and tomatoes together was the ability to harvest them at the same time but I read numerous gardeners reporting that their tomatoes, basil or both plants seemed to benefit from the pairing.

Companion Plants for Basil
Companion planting basil with chamomile will be beneficial to the growth of your basil plants.

Common rue and sage are poor companion plants for basil and should not be grown near basil.

Basil & Anise
One of our sources said that growing anise near basil is beneficial and another listed anise as a bad basil companion plant. Another source explained that anise will cause the essential oil production of basil to increase. If you are growing enough of each type of plant, perhaps try planting a single pair of plants together to see how it goes.

How to Grow Basil

When basil seedlings are about an inch tall, thin so that each plant is two inches apart.

Wait until your basil seedlings are at least 3 inches tall before transplantation. Basil seedlings should have two sets of true leaves, so don’t rely entirely upon the height of your plants. Transplant basil seedlings to a sunny location in your garden but be prepared to provide some shade during the hottest part of the day to young plants. Plant a foot apart in rows separated by 15 to 18 inches. Growing basil as border plants may require a bit more tending and removal of weeds between the plants. Basil prefers light fertile and somewhat dry soil that’s as free from weeds as possible. When plants in adjoining rows meet, cultivation may stop.

Be mindful of mid-day sun as growing basil plants may find it too hot. And, avoid windy locations as the wind can burn young growth.

You can begin gathering foliage in midsummer when the plants start to flower (once the basil plants flower, the flavor decreases) by cutting individual basil leaves or leafy stems. It’s best to cut the larger leaves of your basil plant first. If you harvest/cut the plants back every few weeks, it will encourage new growth and delay flowering. To extend your basil growing season, cut plants down to within a few inches of the ground to get a second and even a third crop. A little bit of fertilizer after pruning is helpful.

Basil Propagation
Allow some of the strongest plants to remain uncut. Seeds should be ripe by mid-autumn and can self-seed.

Over-Wintering or Growing Basil Indoors
Transplant from the garden or sow seeds in early September. Sow seeds two to the inch and transplant seedlings into pots or boxes. A standard 4-inch pot is the perfect size for a single plant. If grown in flats, basil plants should be spaced 5 to 6 inches apart in each direction.

Growing basil indoors requires a sunny window. It is among one of the easiest of the culinary herbs to grow on a kitchen windowsill. Unfortunately, basil grown indoors does not have as much flavor or fragrance as basil grown outside.

Basil seeds take between eight and 14 days to germinate and emerge from the soil. After germination, look for the first set of true leaves two to three weeks later. Then, two to three weeks after the first set of true leaves emerge, basil plants should be about 6 inches tall and ready to plant out in the garden.

A spot that remains around 70 degrees Fahrenheit (21C) provides the right germination environment. Basil seeds require frequent moisture but cannot tolerate over-watering. The best way to water is to mist the seed flat when it starts to feel dry to the touch. sfgate

Basil benefits from aggressive pruning - Scott