How To: Grow Hydroponic Basil

By: Chris | Last Updated: December 16, 2020

The herb strewn atop your pizza or stirred into the most delectable red sauce has been around a lot longer than you think. Ocimum basilicum, part of the mint family, has a long and storied past. 

Anthropologists have found basil in ancient Egyptian tombs, and it seems to have been part of the burying and embalming rituals of the time. 

It is linked to mourning in Greece and religion in the ancient realm of India. Basil is used in food from cultures worldwide, from salads to sauces to pesto and everything in between.

Adding hydroponic basil to your indoor garden is a great way to improve your at-home culinary arsenal!

Germinating Hydroponic Basil

Days to Germinate: 3-10 | Temp: 60-75°F | Heating Pad: No | Grow Light: Yes

Hydroponic basil grows fast and is incredibly easy to germinate. I normally germinate basil using the paper towel method but have also had really good results when I plant hydroponic basil directly into rockwool cubes.

One advantage to planting in rockwool, or starter plugs, is that you can acclimate the seeds to a weaker hydroponic nutrient solution early on. This allows the nutrient strength to be increased sooner than if you’re using paper towels to germinate.

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Regardless of how you germinate, basil seedlings should sprout in 3-10 days. You don’t need a heating pad to germinate basil seeds, but warmer temperatures will accelerate the germination process.

As soon as the plants begin to sprout, place them under a grow light. If you’re using paper towels, leave the container lid on loosely to maintain a little humidity, otherwise, the paper towel will dry out quickly.

Note: Basil, even hydroponic basil, is susceptible to damping off. This soil-borne fungus loves a damp atmosphere. Remove lids or covers used for humidification as soon as seedlings emerge.

Hydroponic Basil Fact Sheet

Growing Hydroponic Basil

Basil will fit well into an existing system of your choice, as long as you have room to get to all the plants for pruning. One thing to keep in mind is that basil loves light, make sure you grow it along with other plants that can tolerate extended lighting periods.

Basic Hydroponic System Management

Maintain a pH level of 5.5-6.0 for optimal production.

An EC range of 1.0-1.6 is recommended. Start plants out on the weaker end, and strengthen the solution as they mature. I germinate seeds with a solution strength of 0.50.

A hydroponic solution that supports vegetative growth will promote healthy hydroponic basil. I normally grow basil and butter lettuce together since their pH and EC ranges overlap.

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Space basil plants 8-10 inches apart so they have room to grow and are free from obstacles. 

Hydroponic basil grows best in temperatures of 65-80°F and moderate humidity. 

Basil requires 14-16 hours of light a day and will grow well with fluorescent lighting. If you’re using T5 fluorescent lighting, bulbs with a 6500K frequency are best suited to supporting leafy greens like basil.

When to Prune Basil for the First Time 

Prune basil for the first time once the plant reaches 6” tall. To prune the plant, use scissors to clip the main stalk just above a growth node. This will encourage the plant to bush out rather than grow vertically. If you don’t prune basil, it will quickly begin to grow vertically and bolt.

How to Prune Basil

Basil leaves are incredibly delicate, so be careful not to bruise leaves while pruning. Bruised basil leaves will emit that fantastic basil smell, but will quickly lose their flavor and begin to wilt.

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Regular pruning will support healthy growth in the plant. If you really want to develop bushy basil, your first pruning should cut to just above the bottom two leaves on the plant. Never prune a basil plant below the bottom two leaves.

Don't Do This to Hydroponic Basil

As flower buds begin to form, pinch them off to divert energy and nutrients back to leaf development. After all, we’re trying to grow basil leaves, not flowers.

Common Pests & Diseases

One of the advantages of indoor hydroponic gardening is the increased control we have over pests and disease, but there are still precautions that should be taken to ensure a healthy crop.

Basil is susceptible to pythium, try to keep humidity low during the first couple of weeks after sprouting to reduce the risk of fungal development. These fungi are very difficult to get rid of and could ruin your basil crop. 

Best Hydroponic Basil Varieties

There are many varieties of basil and several that grow well hydroponically. Genovese and Elindra are the traditional types of basil most gardeners are used to seeing in the kitchen, and their broad leaves would offer excellent flavor to future culinary dishes. 

Hydroponic Purple Basil

Additionally, there are several basil varieties that feature purple leaves, providing a great addition to both your plate and palate. These include:

Harvesting Basil

As evidenced by the pruning section above, basil is a “cut and come again” plant. Harvesting one to two-thirds of the healthy leaves on the plant will spur new growth. Basil should be maintained even if you can’t use the leaves immediately.

Freshly Harvested Basil

Alternatively, you can also pinch off leaves as needed.

When harvesting basil, harvest from the top and prune down the plant to maintain healthy growth.

Storing Basil

Post-harvest, basil is very fragile and has a limited shelf life. It cannot be stored under 50 degrees Fahrenheit or it will turn black. 

Placing basil in a glass of water at room temperature can prolong the shelf life.  If basil cannot be used immediately for cooking purposes, it can also be made into salsas, vinegar, or infused oils for later use. 

Why You Should Grow Hydroponic Basil

Because basil breaks down quickly, it is usually added at the last minute of cooking to preserve its flavor and texture. But basil is more than just an herb that tastes good. 

Filled with the macronutrients of Vitamin K and calcium, as well as antioxidants, basil can lower cholesterol levels, improve mental health, eliminate free radicals, help your body fight cancer, and improve liver health. 

Basil is also known to combat inflammation and aid in battling infections. With so much going for it, having a steady supply of fresh basil at your fingertips is a wise idea. 

Buying fresh basil leaves gets expensive, but now that you know how to grow basil hydroponically you won’t have to worry about that!

Chris Cook started Happy Hydro Farm to share his passion for hydroponic gardening! Growing your own food is incredibly rewarding both physically and mentally. His mantra - "Take excellent care of your plants, and your plants will take excellent care of you."