If you’re new to basil, growing the herb can prove to be a handful. Between seed selection and providing the right soil, light, water, and fertilizer, planting and caring for basil is a steep learning curve.
Just when you think that the herb is growing well, pests and diseases could ruin the whole harvest. You need a full guide to walk you through this complex process.
What does basil need to grow? Basil needs rich, loamy, well-draining soil to grow successfully. It also requires between 6 and 8 hours of sunlight every day during the spring and summer. Regular, deep watering is a must to keep the soil moist but not wet. Ideal temperatures should be 70℉ during the daytime and 50℉.
Basil might be a demanding herb to grow, but don’t let that intimidate you. This full guide has everything you need to know about growing, caring for, and harvesting basil.
Basil Care & Maintenance
Basil care starts when you choose the right basil variety and continues long after you’ve started harvesting the aromatic herb. Since the harvest season is relatively long compared to the short life of this annual, you can expect to put in some work to keep the plant growing successfully.
Basil Seed Selection
The quality of the basil seeds will determine whether you’ll have a good crop or not. This is why you should get your seeds from reliable sources such as your local nursery.
Not only will that ensure good quality of the seeds but also that they will grow in your particular microclimate. If you’re buying the seeds online, make sure the provider has the right certification.
Germinating Basil Seeds
If you have a short growing season, you can start basil seeds indoors about 6 weeks before the last frost. Fill a tray with potting mix, and plant the seeds a quarter inch deep, or sprinkle them on top of the tray, and cover them with a thin layer of soil.
Water the potting soil to get it moist, and keep the tray in a warm and sheltered place with the temperature staying above 50℉ at night and below 70℉ during the day.
Transplanting Basil Seedlings
After the threat of the last frost is over and the soil becomes workable, transplant the basil seedlings to the garden. Choose a sunny spot facing the west or south that gets between 6 and 8 hours of sunlight.
Make sure the nighttime temperature doesn’t drop below 50℉. Plant the seedlings in rows 12 inches apart, and keep between 10 and 12 inches between each seedling.
Ideal Soil for Basil
Basil prefers soil that is rich and drains quickly. Loamy soil is ideal for basil since it has good water retention but doesn’t get waterlogged. Avoid clay and sandy soil. Check the soil pH before planting the basil seedlings and once every 3 to 4 weeks after that. Make sure the pH levels are between 6.0 and 7.5 for optimal growth.
Basil Light Requirements
Light is essential for the success of basil regardless of what variety you grow. In general, the herb needs 6 to 8 hours of direct sunlight during the spring and summer.
For potted basil, place the pot on a window sill facing west or south. Basil in the garden should have direct access to the sun, so avoid planting it under the shade of shrubs or larger plants.
You can use grow lights with indoor plants if you don’t get enough sunlight in the spring. Place the grow lights 1 foot above the basil plants, and keep them on 12 hours a day.
Basil thrives in moist soil. This will require regular watering. Water the plants once or twice a week depending on the weather. In any case, don’t allow more than the top 1 inch of the soil to go dry between irrigations. Water the basil deeply, and aim for the base to encourage the root system to grow deeper in the soil. If the soil dries out too fast, use mulch to improve water retention.
To give basil a good start, mix the soil with plenty of organic materials before transplanting the seedlings. Use organic compost once every 3 weeks to encourage healthy leaf growth. Avoid chemical fertilizers that would stress the herb with sudden growth and might impact the flavor of the leaves.
How To Prune Basil
Because of its short lifespan, basil is prone to flowering within the first 6 weeks of its life. Flowering takes up all the plant resources, leaving little to grow new leaves. To avoid that, pinch off the central stem of the basil herb during the sixth week.
This will prevent flowers and also encourage a bushy growth for the plant. Remove any damaged or diseased leaves to prevent the spread of the infection to other leaves.
When the basil plant is 6 to 8 inches tall, you can harvest the mature leaves without impacting the plant’s growth. The best time of day to harvest the leaves is in the early morning. The heat of the sun causes the leaves to wilt and dry out a little. The more you harvest the leaves, the more the plant will replace them with new growth. Pick no more than four to five leaves per plant at a time.
How To Store Basil After Harvest
Once harvested, basil leaves wilt and dry out rather quickly. If you pick more leaves than you need, you can store the extra leaves in the freezer. Place the fresh leaves in a Ziploc bag, and remove the air from the bag before putting it in the freezer.
You can also dry the leaves to preserve them longer. Spread the fresh leaves on a paper towel, and keep them in a dry and well-ventilated area. The leaves will dry within 2 to 3 days, and you can keep them in a jar for later use. Note that dry basil leaves lose some of their flavors.
You can also preserve basil leaves by making pesto and freezing batches, or blend basil leaves in olive oil using a food processor before portioning into ice cube trays and freezing.
Harvesting Basil Seeds
When you’ve had enough basil leaves for the season, allow the plant to grow flowers. The flowers will develop seeds once pollinated. The seeds are small and are located at the top of the spent flower.
To collect the seeds, cut the dead flower heads, and crush them in a colander. Remove the petals and debris, and you’ll have the black seeds at the bottom.
Basil Pests and Diseases
Another aspect of caring for basil is to make sure the herb is healthy. That’s not always easy when pests attack it all the time, feeding on the leaves and spreading diseases.
Aphids, thrips, and slugs are the most common pests that you have to contend with. Both aphids and thrips drill small holes in the leaves and new shoots. Such infestations can paralyze the plant and stunt its growth.
Luckily, you can easily get rid of them by hosing them off the plant with a strong stream of water or spraying your plants with neem oil.
To get rid of slugs, pick them up manually, and drown them in a bucket full of soapy water.
Basil is prone to many diseases, and some of them can be fatal, so you need to familiarize yourself with their symptoms and how to treat them.
- Fusarium Wilt: A lethal disease that starts as wilted and yellowing leaves followed by brown streaks on the stems, stunted growth, and finally leaf drop and the demise of the plant. The disease has no cure, so get rid of infected plants before the disease spreads.
- Basil Shoot Blight: Common symptoms include brown or black spots on the leaves and brown streaks on the stems. There’s no cure for basil shoot blight, but good plant ventilation helps reduce infestation.
- Powdery Mildew: This fungal infection is caused by poor ventilation and high humidity. Symptoms include a powdery residue on the leaves and stems. Improve air circulation, avoid overhead watering, and pick infected leaves and destroy them.
How Long Does Basil Take To Grow?
Basil seeds will usually germinate within 7 to 10 days depending on the temperature. You can start to harvest the leaves within 3 to 4 weeks after planting the herb.
Why Is My Basil Light Green?
Healthy basil leaves are bright green. If the leaves turn light green, that could be a sign of root rot due to poor draining soil or overwatering. Check for aphid infestations or powdery mildew infections that could cause the leaves to become light green.
Basil is a warm-weather herb that grows well in rich and well-draining soil. Space the plants 10 to 12 inches apart to improve air circulation. Start harvesting the mature leaves 3 to 4 weeks after planting, and pinch off the top of the plant on the 6th week to prevent flowering.