How to harvest basil seeds (sustainable & saves money)

Harvesting your own seeds is a great way to introduce succession or successive planting into your herb garden. And basil is definitely the best of all fresh herbs to start with.

But there are some pitfalls to be aware in this seemingly very straightforward process.

Just the facts on how to harvest basil seeds: 
1. Let non-hybrid basil plant flower
2. Allow seed heads to dry
3. Gentry crush seed heads over mesh sieve
4. Collect and store dry seeds in airtight container

If you are growing basil, you most likely already know to prune and top your basil for plants to grow strong, compact and high-yielding.

But today we are here to tell you to let at least some of your basil plants flower. And here is why.

Basil flowers are beautiful as well as producing seeds to harvest
Basil flowers are beautiful

5 steps to harvesting your own basil seeds

We harvest basil seeds to grow more basil, not to eat or use the seeds in any other way.

And it is so easy. You only need to let a few plants flower and go to seed. So whether you grow basil from cuttings or prefer to plant basil seeds in pots and containers, make sure to grow two extra plants this season and you will be set for basil seed – for this and the next growing season.

1. Let (some of) your basil plants flower

Resist the urge to prune at least some of your basil plants and watch buds develop and turn into basil flowers. And this also mans that you need to stop pinching the tops on some of your basil plants.

As the basil flowers mature, the basil leaves develop a bitter taste and become inedible. The plant is now using all its energy to produce flower stalks that will produce those vital basil seeds.

2. Let flower heads wilt and dry

Pick the dried flower heads and petals as they appear – but leave the green carpels to mature and dry.

These green carpels or seed pods will turn brown as the basil seeds mature and are ready to be harvested.

3. Cut flower stalks two inches below the dry seed heads

When the seed pods have turned brown it is time to harvest and save basil seeds. Use sharp garden scissors to cut the stalk as the dried seeds pods are fragile and brittle to the touch.

4. Gently crush seed heads to harvest seeds

Place stalks on white paper towel or another soft surface that will provide a contrast to the harvested stalks and dried seed pods.

Use a rolling pin or similar tool to gently crush pods, and then extract and collect seeds.

Use your hands to pick the tiny seeds clean by removing all larger pieces of shell, husk and other plant material. Next sieve the remaining seed material to be left with only seeds.

5. Store seeds in an airtight container

Make sure that seeds are completely dry. Store seeds in an airtight container or plastic bag placed in a dark and dry location.

Before storing the seeds it is advisable to place the container with the seeds in the freezer for 2-4 days to kill off any traces of pest or disease.

When can you harvest basil seeds?

Harvest seeds from mature basil plants after flowering. Basil plants can take anything from 8-16 weeks to develop flowers that will give seeds to harvest.

It is generally speaking easier to harvest basil seeds in the summer as basil likes full sun to grow and develop.

To harvest basil seed from plants growing indoors you need to use grow lights. Especially during the darker months of the year.

Why harvest seeds? I though basil is a perennial herb.

The are plenty of perennial herbs in and around zone 7, but for most of us, basil will be grown as an annual.

You can grow basil outdoors, but wait for the last expected frost date to come and go before transplanting basil outdoors.

Basil is not very cold hardy and does not tolerate frost. This is also why basil is grown as an annual in most grow zones with the possible exception of tropical zones like USDA 11.

Can all varieties of basil seeds be harvested

Yes, but you should only harvest and save seeds from non-hybrid or open pollinated varieties if you are looking to reproduce the actual plants in kind.

Why? Well, saving basil seed from hybrids is a bit of a lottery as the plant you will grow from the seed may have vastly different traits than the plant you originally harvested.

Most seed packets from reputable dealers will state if the seeds are non-hybrid, non-GMO, organic, etc.

Now, there is nothing wrong with hybrid or cross pollinated seeds. Hybrids are often developed for desirable traits like being more disease resistant, draught tolerant as well as generally being more high-yielding. But again, the seeds are a lot less likely to reproduce themselves in kind.

We mainly plant basil seeds from non-hybrids but also grow some hybrids like Lemon basil and Lime basil. Our favourite varieties of basil are sweet or common basil, Thai basil, cinnamon basil, dark opal basil and the classic Italian or Genovese basil.

Harvest seeds from dark opal basil
Dark opal basil with its characteristic look

How many seeds make a basil basil plant?

Do not fall for the notion of planting one single majestic looking seedling all by itself in a pot. It may look great, but truth to be told, you need to plant a minimum of 3-5 seedlings per pot to develop a strong and high-yielding plant.

And when growing from seed, use the same logic when you sow your basil seeds. Scatter seeds generously across the pot and be prepared to thin seedings at a later date as needed.

Saving seeds to save money and more

You need only a few plants to save seeds for an entire growing season. And yes, you will save money.

But as nice as it is to save money – saving seeds is not really about saving money.

For us, it is about saving money and convenience, but also about the satisfaction of creating that same circle of life feeling we talked about when we built our raised garden beds. The same goes for composting and collecting and using rain water for our outdoors vegetable gardens.

What about harvesting green seed pods instead?

Yes, but I do not recommend it. You can save basil seeds from green seed pods by using a sharp knife to extract the seeds and then dry the seeds before storing them. But why rush the process? It mkes no sense.

Instead, let the flowers and pods dry on the plant. This allows the seeds to ripen and mature on the plant to give your seeds the best chance to grow when planted. Do not look for short cuts – mimic nature’s way.

And, I actually find this method to be less work besides the fact that it is a great feeling to try and mimic the natural flow of a plant’s life in nature.

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.