How to grow basil in a greenhouse

Hoe basilicum in een kas te laten groeien - KWEEK

If you are infected with growing in your own greenhouse, basil is part of that! It's relatively easy if you keep two important basic principles in mind.

Basil prefers warm, moist conditions .

A lot of light is needed.

The sun does the rest. Besides the many possibilities to use it in dishes, it is also simply a beautiful herb with a strong aroma that can even help to keep vermin at bay. And believe me, there is nothing tastier than fresh basil from your own garden.

Where does basil come from?

Basil, or Ocimum basilicum , is a member of the Lamiaceae family, or the mint family! Like mint, basil is a tender, edible plant commonly used in kitchens and added to salads. While basil is commonly found in Italian and Thai cuisine, it first originated in India .

How does it work?

Basil is one of the easiest herbs to grow in a greenhouse environment, provided it gets plenty of light. To get started, you first need to decide what type of basil you want to grow (or varieties) and where you will plant it: in an in-ground bed or in pots .

There are over 150 known varieties of basil to choose from, all of which can be grown in greenhouse conditions. Each variety has a different appearance, color and even flavor profile. So make sure you choose a variant that suits you well.

Kind of basil




Compact growth with small spherical leaves

Intense and bold (hints of cinnamon and mint)


Ornamental leaves with dark purple variegation

Mild, sweet


Larger leaves and can grow up to 2 feet tall

Sweet with a slight spiciness, perfect for pesto and sauces


Rounded, cupped, serrated leaves

Slightly spicier than Genovese


Thick, deep purple leaves


Red Rubin

Compact, red-purple leaves

Sharp, strong taste


Longer, larger leaf shape

Less mint flavor than traditional Italian basils

Thai basil (or sweet Thai basil)

Leaves with purple veins and purple stems

Anise, liquorice and clove flavor (generally sweet)

Siam Queen

Purple stems, light green leaves

Very spicy and intense flavor, great for soup

Lemon Basil

Thin, light green leaves

Anise, basil and lemon combined

Cinnamon Basil

Dark green leaves, cinnamon-colored stems

Spicy cinnamon flavor

Christmas Basil

Shiny, green leaves with burgundy stems

Classic basil flavor with a mix of fruity sweetness

Fertilization requirements

If the soil where your basil is planted is rich in organic matter, you can fertilize your basil sparingly. For example, you can use a fertilizer with an NPK ratio of about 5-10-5, diluted significantly and only during the growing season.

However, be careful not to over-fertilize your basil as this can affect the flavor and aroma.

Grow basil from seed

If you are growing basil from seeds, you can start them in a heated greenhouse or use a heat mat under the trays. Whatever you decide, the soil temperature should not drop below 70°F and the ambient temperature should be at least 55-60°F. Keep in mind that the warmer the soil, the faster the seeds will germinate, but if they are too hot, they may not germinate at all.

Fill a seedling tray with a seed starter mix and add 1-2 seeds per cell. During the first weeks it is important to keep the soil moist, but not soaking wet.

When the young basil plants have more than five true leaves, transplant them to the final growing area. You should plant the seedlings at least 4-6 inches apart to allow enough room to develop properly.

How long does it take for basil to grow?

When basil is started from seed, it usually takes about 5-14 days to germinate. The exact germination rate can vary between different types of basil. In addition, soil temperatures that are too high or too low can delay germination, so provide conditions that are moderate in temperature.

What can you easily combine with basil

A spears are an excellent choice to grow along with basil, as the combination of the two attracts ladybugs, which feast on common pests such as aphids. In return, basil helps repel asparagus beetles. Finally, asparagus grows quite tall, so planting it accordingly can give a little afternoon shade to your basil.

Marigolds are an excellent natural pest repellent. When grown together, basil and marigold keep pests at bay and attract beneficial insects.

While basil generally prefers greens for companions, flowering herbs such as chamomile, oregano and chives have similar care requirements and can even improve the flavor of your basil plants.

Tomatoes and basil are not only friends on the plate, but also in the ground! Basil is very helpful in deterring tomato hornworms and increasing the yield of your tomato plants.

Peppers are another great companion for basil, even if their friendship is one-sided. Basil is great at increasing humidity for pepper plants, helping them grow faster.

Root vegetables are often a target for pests because of their fragile and delicious foliage above the ground. Planting some basil next to your root vegetables, such as carrots, beets, or radishes, will benefit your vegetables, as basil is a great deterrent to pests.

What is better not to plant together with basil

While basil can improve the growth (and even the flavor) of other herbs and vegetables, there are a few types of plants that should not be planted right next to your basil:

Cucumbers are mostly water, so they tend to absorb other flavors easily. Therefore, unless you intend to produce basil-flavored cucumbers, it is best not to plant them closer together.

While you won't run into too many problems if you plant your rosemary close by, you'll want them to grow in separate pots. Rosemary has different care requirements than basil, particularly in terms of soil conditions, so to avoid watering issues it's best to keep them separate.

Rue and basil are not buddies for several reasons. First, rue is a natural growth inhibitor, which can stunt the growth of your basil plants. These plants also prefer drier soil conditions, making them incompatible with basil.

Sage is very similar to rosemary in that sage also prefers drier soil conditions. Unfortunately, this would eventually make sage incompatible with basil when potted together.