Gardening in Hawai’i with Tom Timmons: Basil — the royal herb

On a dismal day, the gray clouds suffocating my good humor, and the blustery wind tattooing cold beads of despair on my forehead, all my good intentions forsaken, I rub a leaf of basil between my thumb and forefinger, hold it under my nose and inhale deeply. 

Ah! The skies clear, the sun shines warmly, and all is well in my little old-man world. I understand now why it is sometimes called the royal herb or the holy herb.

Basil is magnificently fragrant. 

Different varieties emphasize different fragrances: lemon, licorice, lime or cinnamon.  Regardless of the variety of basil, it will add character, charm and subtle magic to your cuisine.  Fortunately, growing basil is easy and does not demand that you use different techniques for different varieties.

Basil has a large root system. When selecting a pot, choose one that allows the roots to grow laterally (widely) rather than deeply. Don’t forget: the pot needs weep holes at the bottom that allows excess moisture to drain off. 

Fill the pot with a quality potting soil that is slightly damp. Compact it slightly. Cover the seeds with about a quarter inch of soil and tamp it down, but not too tightly. 

During the germination period, I use a spray bottle to keep the soil moist but not wet. It is important to remember that basil is a tropical herb — you know, palm trees gently swaying in a warm breeze with smiling sun overhead. Try to find a little tropical spot that is warm and sunny in your house, on the deck or on the lanai. 

Like all herbs, basil will need at least 6 plus hours of sunlight to grow successfully. If all goes well, in 10 days or less you will have little basil sprouts. Although I prefer growing in a pot, growing basil in the garden is easy because basil is tough. Even a lazy gardener with little knowledge can grow basil in the garden.

However, growing does not mean quality or quantity. So, let’s do it right and enjoy some quality basil! Dig a hole about 18 inches in circumference and 8 inches deep. I add compost and organic matter to the soil. 

Thoroughly mist the soil so that it is uniformly damp before refilling the hole. I leave a small hole where I put a four-inch pot.  Fill all around it, remove the pot and add commercial potting soil. This is where I plant the seeds. Just in case I got the soil a little too wet, I don’t plant until the next morning to let the water drain. 

Plant the seeds about a quarter inch deep. Until the seeds germinate, use a spray bottle to keep the soil moist. Since you are outside, you cannot control the rain or temperature.

In Hawai’i, the temperature shouldn’t be a problem. But during certain times of the year, it seems as if it will never stop raining. Anticipate the seasonal weather to choose your planting date.

Basil likes a good meal now and then before it becomes a good meal. If you are growing in pots, you probably need to add a bit of fertilizer once a month. In the garden, add fertilizer every couple of weeks.

I don’t recommend using dry, commercial fertilizers. I seem to get the best results from top dressing the soil with compost or using compost tea and worm castings. Liquid fertilizers such as MiracleGro and Fox Farm are good choices, or purchase your personal favorite.  Look at the label and choose one that has more Nitrogen (N) than Potassium (P) and Phosphorous (K); nitrogen is normally the first number when three are listed (example, 4-4-4).  Remember, nitrogen encourages leafy growth which is the part you want to harvest. 

Downy mildew can be a problem with basil. It appears first on the lower leaves of the plant and moves quickly up the plant. The top surface of the leaf turns yellow, and the underside of the leaf will have a gray fuzz. There is no magic elixir that will get rid of it. Remove and destroy the plant.

Prevention is the key. When purchasing seeds check the label or the seed catalog for DMR. This indicates that the seeds are resistant to downy mildew. Plant in an area that receives plenty of direct sunlight and has good airflow. You and your basil will be happy. 

Basil always thought it would be happier if it just had pretty flowers. It may be happier, but you won’t be happy with the bitter taste of the leaves if you allow it to flower. When the plant produces its first flower bud, pinch it off. Basil also does better if you prune it regularly. 

Basil seems to relish the attention of having its leaves clipped. Regular clipping not only gives you fresh basil for salads and cooking, but it also stimulates the plant’s growth.

Don’t trim as if you are Jack the Ripper; you can damage the plant. Where you snip is important but snip often, so the plant doesn’t get too big.  Pick a stem that has multiple buds (a grouping of leaves with a stem both above and below) and cut back from the top leaf bud to the lowest leaf bud that attaches to another stem. 

A word of warning: don’t use your wife’s good sewing scissors for pruning unless you have a death wish by slow, twisted, diabolical methods that would make Satan cringe in horror.

I am using trimming, pruning and harvesting of herbs synonymously. In Hawai’i, if you take care of the plant, it lives for quite a long time. Unless you have a big family, you probably will have more basil than you can use. 

Drying is the most common way of preserving basil, but freezing it is the best way of preserving the fresh-picked flavor of basil. I always give some to my neighbors. This is a bit self-serving, but rewarding. Sometimes they will bring me a generous helping of whatever they put the basil in. 

What poet Robert Frost should have said: “Good basil, makes good neighbors.”

Nutritionally, basil is terrific.  According to WebMd, “Basil contains many vitamins and minerals, as well as antioxidants such as lutein, zeaxanthin, beta-carotene and beta-cryptoxanthin. Many of basil’s health benefits come from these antioxidants, as well as its essential oils.” 

So, get with it: plant some basil seeds and begin enjoying all the benefits of fresh basil.

References:

• Belsinger, Susan and Tucker, Arthur. Grow Your Own Herbs. Kindle Ed. Timber Press, Portland, Oregon. 2019.
• Editors: The Old Farmersʻ Almanac. “Growing Basil: Planting, Growing and Harvesting Basil.” www.almanac.com/plant/basil. 2021
• Green, Benjamin. Growing Herbs for the Beginner. Kindle ed. 2016. 
• Schuh, Marissa and Grabowski, Michelle. “Basil Downy Mildew.” https://extension.umn.edu/disease-management/basil-downy-mildew#resistant-varieties-1217710. 2022.
• Therapeutic Research Faculty. “Basil – Uses, Side Effects, and More.”  https://www.webmd.com/vitamins/ai/ingredientmono-303/basil. 2020.

Editorʻs Note: Every other week, Big Island Now will feature a guest gardening column by Tom Timmons. He is a certified Master Gardener respected for his gardening experience, but his views are not necessarily those of the University of Hawai‘i.

For more information about the Kaua‘i Master Gardener program, click here.