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How to Germinate Basil Seeds (Properly!)

Hands holding tiny pot with a small basil seedling

Basil Seed Germination

I think every gardener goes through the phase of planting seedlings and eventually takes a whack at starting a plant directly from seed. After all, it is a natural evolution to learn how to garden right from the start!

Sometimes this process can be tricky! There are some plant seeds that take a little bit more coaxing in order to germinate, whereas others simply sprout up without a care in the world.

Basil seeds however, land somewhere right in between. If the seeds are new they’re usually read to grow, but if they’re a little bit older, their chances of germinating are a little bit lower.

This article is going to go through some reasons why basil seed germination can go awry as well as some solutions to make sure the process goes smoothly! We’ve also gone through all sorts of other basil care topics, so take a look:

Basil is sensitive to cold weather, learn the ways to protect them here!

Pests love basil just as much as we do, learn how to keep them at bay.

Want to know what basil bolting is? We’ve got the answers here.

Basil leaves grow super fast, learn how to properly harvest those leaves here.

Is your basil plant browning? Learn the reasons why over here!

Dying basil can be for so many reasons, learn them here.

Why does a Basil Seed Have Trouble Germinating?

Paper towel holding tiny germinated basil seedlings

The more you learn about growing basil, the more you start to realize just how picky they really are! Basil likes to be right in the center of growing conditions.

Basil seed can struggle to germinate for a number of reasons. Knowing that mature plants are so sensitive, imagine how sensitive an unestablished seed or seedling can be!

Temperature

The main and most common reason why basil seeds struggle to germinate is that they have been exposed to cold temperatures. It is important that the seeds are in a cozy and warm location as they’re getting started.

Planting basil seeds outdoors before the last frost date is detrimental to their growth and can even kill them. If you’re growing basil indoors, even having the pots too close to a drafty window can cause them harm.

Soil temperature is also very important! Many people think that the temperature of the air is most important, but soil also holds a lot of temperatures. A way to maintain soil temperature is by adding a layer of mulch to the area to keep it warm.

Moisture Level

As basil seeds are first getting established, they really need to appreciate being in moist and humid conditions. If the seeds are left to dry out even for a couple of days, they may not be recoverable.

Humidity is another important growing condition for your young seeds. This is why gardeners will often cover their seed starter trays with plastic lids to create a little microbiome in there.

Light Exposure

Basil seeds need light in order to germinate. Sometimes gardeners will make the mistake of burying seeds a little bit too deep in the soil. It can be tricky achieving the right depth!

Too shallow and the seed will dry out and won’t germinate, and too deep and it won’t get enough sunlight to be encouraged to pop a little seedling out.

How can you Encourage Basil Seeds to Germinate?

Bunches of basil microgreens sprouting up

Despite all of those tricky issues, there are some ways to ensure that your seeds are as happy as possible. All it takes is a little bit of time, patience, and effort. Here are some tips for preparing for planting seeds:

Planning

The best favor that you can do for yourself is to plan out when the best time will plant basil seeds. Things like temperature and amount of bright hours per day will really help!

If you live in a cold area and you want to plant grow basil outdoors, make sure to check when the last frost date of the season is. This will indicate when the growing season can begin. You don’t need to worry if you live in a warm area.

If you’re planning on growing basil indoors, you start your seedlings 6-8 weeks before the last frost date. Just make sure to pick an area that receives enough sunlight and is warm as well.

Proper Planting

The best way to start basil seeds indoors (especially if you’re planning on growing a bunch) is to get a seed starter cell pack with a clear plastic lid and a large tray that will fit underneath.

If you have older seeds, place 3 or 4 seeds in each cell so that at least one of them is hopefully viable. If you have newer seeds, 1 per cell will be fine.

Pick a spot in your home (or outdoors if it’s over 70 degrees Fahrenheit) that receives a ton of sunlight. Basil seeds require light in order to germinate.

When you’re planting seeds, each should one should be planted about 1/4 inch deep into the soil. It is important that they’re not so shallow they dry out, but still shallow enough that they can receive sun exposure.

Hands transplanting small basil plants into the garden

Maintaining Moisture

There are a few ways that you can ensure your basil seeds indoors can remain moist. It is advised to avoid watering basil from overhead, as this can dislodge the seeds and delay their growing process.

It’s better to fill the tray that you’ve placed under the cell pack and fill it with water. This way the soil will absorb as much water as it needs. Pour out the remaining water so that it doesn’t become waterlogged.

You should also be misting the seeds every day. Simply lift the clear plastic tray each morning and mist each of the individual cells and put the tray back down. It will create a very warm and humid environment for them.

Extra Tips

Soaking – though young basil seeds are usually always viable, you can speed up the germination process by soaking the seeds before planting them.

Simply soak the seeds overnight in some distilled water. It is better that the water is warm for the little seeds. They will germinate super quickly once they’re planted.

Heating Mat – if you’re really worried about the temperature of your home or if temperatures really dip at night time, you can always get a heating mat!

This is a mat that you can plug in and place underneath the seed starter tray. It will maintain whatever temperature you set it to, making sure the seeds are consistently toasty!

How can you Tell a Basil Seed has Germinated?

Happy germinated basil seedlings growing sets of leaves

If all has gone right – the basil seeds were viable, you’ve maintained the right growing conditions – the basil seeds should have germinated in 5-10 days to create precious little basil seedlings!

Around that time you should start to see tiny little basil leaves popping out of the surface of the soil. These are your first basil seedlings! Once those first tiny leaves pop out, the growing will really begin because it is finally able to photosynthesize.

Within 2-3 weeks, the first set of true leaves will probably have grown in on your basil seedling. True leaves are large, bright green, and around 2 inches in length. Once your plant has 4 sets of true leaves, your basil plants will be ready for harvesting!

The Next Step…

Now this is just the beginning! We’ve written articles about how to properly harvest basil leaves, how to prevent the basil from flowering, and how to harvest basil seeds once they’ve come in! Check them out!

What are some popular basil varieties?

Two different types of bright green basil and purple basil

Ocimum basilicum is the main variety of basil from which many other varieties are derived from. Here are some of the most popular and lesser-known basil variety options.

Sweet Basil – sweet basil (Ocimum basilicum) is the cornerstone for most other basil. It is very commonly used as fresh basil, though it also tastes very good dried.

Sweet basil has that classic spicy and sweet flavor. Plants grow to be 8-20 inches tall and have bright green leaves that are highly fragrant.

Lemon Basil – lemon basil is a super popular fresh herb throughout Asian cuisines. It has that classic sweet/spicy flavor but with a nice lemon-y kick to it.

A lemon basil leaf differs from a common basil leaf, in that it is more narrow and has serrated edges.

Lime Basil – lime basil is a hybrid of lemon basil! It looks and smells super similar but it has more of a lime-y kick to it than lemon. Those who aren’t picky about their citrus probably won’t be able to tell.

Holy Basilholy basil is a basil variety that is less used as a culinary herb and more used as a medicinal herb. It has a long history in folk medicine and is often made into herbal tea.

Genovese BasilGenovese basil (also known as Italian basil) is the type of basil you need if you’re looking for a vigorous grower. This basil type can grow to be over 3 feet tall and has leaves that are about 3 inches long!

Genovese basil leaves are super fragrant and have more of a sweet than spicy flavor. These are used when you want to make pesto, Caprese salad, or a basil cocktail.

Purple Basilpurple basil is very commonly used as a fresh herb for its gorgeous color. It has dark purple leaves with serrated edges and is spicier than it is sweet.

Cinnamon Basil cinnamon basil is a lesser know basil variety and it has two-toned leaves with serrated edges. Leaves have a purple center and green edges and it is commonly grown and used in the middle east.

Green basil and purple basil growing in rows in the garden

FAQs

What is the ideal type of potting soil for basil plants?

Basil plants like potting soil that is well-draining, light, moist, and full-on nutrients. It is important to keep the soil moist, so well-draining soil is important as they do not appreciate having wet feet.

You can incorporate some compost into the potting mix if you’re worried about the nutrient level. Not only will compost increase the fertility of the soil, but it will also increase drainage as well! Yay for compost!

How much sun exposure does a basil plant need?

Basil plants are sun lovers, but the amount of sunlight exposure they wish to receive will depend on the temperature. If it is super hot they’ll need a bit more shade, but if it is cooler they love to be in direct sunlight.

If you’re growing basil indoors and feel like you don’t have enough sun exposure, you can opt to get a grow light! Set the timer on your grow light to 8-10 hours and that should be a sufficient amount of sun for the plant.

When is the best time of year to sow basil seeds outdoors?

The time of year that you should sow basil seeds outdoors depends on the climate of the place you live. If you live somewhere cool, you’ll have to find out when the last expected frost of the season is, and you can sow seed after that.

If you live somewhere that is warm all year round, you could essentially sow basil seeds at any time of year.

What do you need for seed starting?

When it comes to seed starting, you won’t need all that much. You’ll need a well-draining potting mix, some seed trays, a tray to put underneath, a mister, and some seeds!

What do basil sprouts look like?

Sometimes it can be hard to identify different types of seedlings when they’re so tiny as many plants are green and start out with having small leaves.

Basil sprouts look very much the same as other seedlings would. Basil sprouts are short, green, with spindly stems, and tiny green leaves that emerge in even sets of 2.

What is the lowest temperature that a basil plant can withstand?

Basil plants are definitely not the coldest tolerant of herbs. They will start to suffer when temperatures dip below 40 degrees Fahrenheit but can die if they go below 32 degrees. They tend to perform their best when temperatures hover around 70 degrees.