Grow basil from seeds (5 simple steps)

You only need one healthy basil plant to become self-sufficient. Read on and I will show you how to grow a basil plant from seed and then use that one plant to grow and harvest as much basil as you want.

Basil or sweet basil (Ocimum basilicum) has large aromatic leaves and is one of the more popular herbs to grow from seed among home gardeners.

You may know this herb as Italian basil or "Genovese basil" - one of many popular cultivars or varieties of this popular herb. 

Here today we will show you how to grow basil from seed in a pot or container at home.

Growing basil from seeds in 5 simple steps

Basil is a great first herb to grow from seed. To get started you will need:

  • seed tray, pot or small container with cover
  • potting soil mix (or soil less medium like coconut coir)
  • good quality basil seeds

Here are 5 tried and tested steps to get started growing basil from seeds.

1: Choose a pot or container

We use seed trays or small starter pots. When using starter pots I prefer recycled plastic pots (7 centimetres / 3 inches) that help maintain an even level of soil moisture.

A seed tray will most of the time come with a plastic cover or dome. Starter pots can, on the other hand, quite simply be covered with plastic wrap.

There is no real advantage to planting basil in larger sized grow bags, pots or containers. Seeds should be planted shallow and it is easier to control and maintain moist soil in smaller sized pots and containers.

2: Choose your soil

I use a potting soil mix of equal parts cactus soil mix and regular potting soil. But you can use any quality potting mix that drains well.

Why do we use two different types of soil? We will plant the seeds in the cactus soil mix. The cactus soil mix holds no added nutrition and has a looser structure to allow the seeds to germinate with ease. 

But when the seeds have germinated, the young seedlings develop roots that go deeper and are now met by a slightly more fertile potting soil mix.

This method works really well for me and I believe it helps the seedlings create a stronger and more compact root systems.

Please note that both types of soil are lean potting soil mixes. Seeds do not need extra nutrition to germinate. The seeds themselves hold all the energy needed for the seeds to germinate and sprout first leaves or cotyledons. Overly fertilized soil will burn the fresh and delicate new roots when your seeds germinate.

3: Sow basil seeds

Place or plant basil seeds gently across the surface of your potting soil. Simply sprinkle the seeds across the soil and make sure to space the seeds 1 cm (1/4 inch) apart.

Next, press down on the seeds gently. By pressing on the seeds we remove air pockets and make sure the seeds have contact with the soil. Check your finger tops to make sure the seeds do not stick to your finger tips.

Basil seeds are hard to handle when wet
Seeds are on the small side

Now, cover your seeds with a fine layer of soil or vermiculite to help retain moisture.

To avoid displacing seeds when watering, mist the soil surface using a spray bottle. 

Next, cover the pot with a clear plastic. Make holes in the plastic to ensure good air circulation. Fresh air is important and you do not want to hermetically seal the pot. 

If you see excessive condensation on the inside of your plastic cover you need to improve air flow and circulation.

Should you soak basil seeds before planting? You could as soaking basil seeds will help the seeds germinate faster. I do however not pre-soak seeds when I grow basil as the gemination rate is good and I find it harder to work with pre-soaked smaller seeds. 

Make an effort to avoid placing all seeds in a clump. As the seeds are on on the smaller side, I find it helps when working with 3-5 seeds at time.

Planting seeds too close together will force you to thin the seedlings at a later stage. Keep in mind that basil often has a germination rate above 80% and each seed has the potential to develop into a mature plant. 

Basil seeds grwoing into seedlings in a plastic pot
You do not want young basil seedlings clumped together

Seeds will germinate in 4-7 days depending on factors such as soil temperature and light.

4: Watering the young basil plants

Remove plastic cover and place in location with good light when seeds germinate and sprout.

Place pot in a warm location (20 degrees C / 70 degrees F) with full sun although out of direct sunlight.

Bottom water you seedlings by placing pots in a water bath. Bottom watering is great when working with many pots. Simply place the pots in a container with water. Now let the soil suck up the water through the drainage holes. 

Add pot to water bath to water pots from underneath
Soil turning darker as it absorbs water

As you can see in the photo, the light soil will go darker in colour as it absorbs water from the container.

When the surface of the potting soil is dark and wet, remove the pot and put it on a surface to drain any excess. Again, you are looking for moist but not wet soil. And draining the pot ensures the correct level of moisture.

5: Transplant 3-5 seedling to a larger pot

When the seedlings are large enough to handle (ca 10 cm / 4 inches) we repot the basil plants to a bigger pot. 

When starting seeds in smaller pots, transplant 3-5 seedlings into a larger pots with fertile well draining soil. Or transplant basil seedlings to planting boxes or your outdoor herb garden.

True leaves forming on basil seedlings
True leaves on basil seedlings

If you grow basil in rows you should keep the rows approximately 30 cm apart to promote healthy growth.

When you plants reach maturity you should start feeding your plant at least every 2-4 weeks. Use an organic fertilizer and always start by giving half the recommended dosage.

Harvesting basil plants

The basil plant takes approximately 50 days to grow from seed to mature plant and reaches a height of about 25 cm (10 inches).

You can – and should – harvest basil leaves continually throughout the plant’s life. 

To promote the growth of bushier and more productive plants you should regularly harvest leaves, prune and pinch tops. And remember to feed your plant with fertilizer (organic) if you expect it to keep producing new leaves.

Topping basil is easy. Count the pairs of leaves from the top of the stem. Now pinch the stem just above the third pair of leaves (counting from the top).

The tops you pinch can of course be eaten. Or use the tops as stem cuttings to grow more basil plants.

Can I direct sow basil seeds?

You can direct sow basil outdoors as soon as you have passed the last expected frost date and the minimum temperature is above 10 degrees Celsius (50 degrees Fahrenheit).

But do keep in mind that basil do not like wind or cold weather. And to be honest, as basil is one of the easiest herbs to grow indoors, I do prefer growing basil indoors.

I start basil from seed indoors and tend to keep my basil plants in pots for their entire lifespan.

I do, sometimes, move the pots outdoors. But generally speaking the plants live a somewhat sheltered life in their pots. This also means that my growing season gets extended beyond spring and summer.

And using a grow light I can and do actually grow basil indoors year-round.

Maybe this is also the reason why I have never had serious problems with pests like aphids, fungus or Japanese Beetles. Aphids are common pests when growing basil and here a water based Neem oil spray solution can help you keep the pests in check.

3 common mistakes growing basil from seed

I have been called on by friends and family to rescue basil plants on more than one occasion. It is not that it is difficult to grow basil from seed. Rather, beginners have a tendency to care too much and almost try too hard.

And I can say with authority that overwatering kills at least as many plants to be as underwatering. Mold growth on soil and yellowing basil leaves are indicators that you may be overwatering your basil plant.

Here are 3 common mistakes I see home gardeners do.

1. Warm does not mean hot

Do not confuse full sun with direct sun all day log. Basil plants do like it warm (20 degrees Celsius / 70 degrees Fahrenheit) but not too hot. Protect your plants from direct sun especially during the hottest times of the day.

2. The basil plant do not like wind

Basil can be grown outdoors but it is a quite tender annual herb. Protect your plant from wind my choosing a protected spot in your garden or use companion planting to shield and protect your basil.

3. Overwatering your basil

Seeds need moisture as well as oxygen to germinate. If you overwater you will drown your seeds and they will rot and you never see any growth.

Also, basil seedlings will not survive if the root system is sat in constant wet. Your plant will suffer root rot and roots will start to smell and turn dark and slimy.

This is why it is so important to us a soil that drains well. You want the soil to be moist but never soaking wet.

Keeping the basil plants in pots gives me control. I move my plants to where they want to be given the external conditions. And this works for me. But you can of course plant your basil plants outdoors in your herb or vegetable garden should you prefer.

Frequently asked questions

Meet the author: Mattias is an experienced gardener spending most of his free time on his knees among herbs, plants and garden vegetables. For the past two years he has been sharing gardening projects and how-to tutorials on the NordicLavender website and YouTube channel.