Hydroponic Basil Guide | Choosing Varieties & Production Advice

Some field crops get by with little attention for long stretches, but hydroponic crops, basil among them, need daily management and do best when conditions are tuned to the crop. The most important factors are temperature, pH, light, daily light integral (DLI), electrical conductivity (EC) and nutrient makeup. Basil generally likes warmth, moderately acidic pH, fairly low EC and strong light, though exact needs vary with the system, season and other factors. As a general starting point for hydroponic basil:

• Temperature: 65–70°F (18–21°C).
• pH: 5.8–6.2 (a little higher in aquaponic and organic systems).
• Light: At least 14 hours a day.
• Daily light integral (DLI): At least 12 mol per m² per day; more is better, since basil thrives in strong light.
• EC (Electroconductivity): 1.0–1.4 mS/cm, depending on season; winter crops need higher EC than summer crops.
• Nutrient Solution: Use a nutrient solution made for herbs and leafy greens that suits your water, and follow the label to reach the EC above.

To learn more about monitoring and managing nutrients and light, see our detailed guide to starting healthy hydroponic seedlings.

If hydroponics is new to you, also check out our hydroponics primer, covering the basics of the most common systems.

Growing basil apart from other crops lets you adjust the nutrient solution and environment just for it; basil grown in conditions set for a different crop may struggle.

Run your own trials on site to find the inputs and conditions that work best in your system.

Most commercial growers use 3–6" pots for retail herbs. For basil, a 4" pot strikes a good balance between using space efficiently and growing a plant big enough to look good and sell well.

Sow seed straight into the retail pot or into plug trays, then move plugs into retail pots after 2–3 weeks to finish.

The seeding rates (seeds per pot) below cover a wide range. With fewer seeds, you'll get an attractive pot as long as plants have ideal conditions, with plenty of light, room and time to fill in. With more seeds per pot, you'll get a fuller look sooner, but plants will outgrow the pot faster.

For more growing tips, see our basil growing information.

Sleeved 'Genovese' basil, grown on an ebb-and-flow bench, ready for market.

Photo courtesy of a retired seed sales representative.

Full-size (not microgreen) basil grown in containers or hydroponics is usually sold in one of these ways:

• Live plants with the growing medium still on the roots.
• Live plants in pots.
• Loose leaves or bunches in bags or clamshells.
• Baby-leaf basil grown on hydroponic rafts, cut at 4–6" tall and packed in bags or clamshells (less common).

Slipping live plants into protective sleeves helps prevent damage at market and extends shelf life.

Almost any basil type or variety can do well in hydroponic and container systems, so how do you pick the best one for you? Weigh growth rate, disease resistance, habit, leaf type, yield, and flavor and aroma.

Plant Habit & Growth Rate

Basil variety chart

For live plant sales, choose varieties that make compact, attractive, full, uniform plants.

If you mainly sell leaves or bunches, leaf type, yield and flavor matter more than plant habit.

For any product, slow-bolting varieties lengthen the harvest window and fast growers shorten crop time for quicker turnover.

To compare habit, growth rate and other traits, see our basil variety chart.

Flavor, Yield & Leaf Type

The two main green basil types side by side: Genovese (left) and Italian large leaf (right).

Green basil comes in two main types, which differ in flavor, yield and leaf shape.

• Genovese basil is valued for its classic pesto flavor and its strongly cupped, spoon-shaped leaves, and it's the type most cooks prefer.
• Italian large leaf basil is very productive, with dense plants and big, pointed, crinkled leaves that are usually thicker and sturdier than Genovese leaves. That toughness, along with high yields and fast growth, is why some growers favor it, though its paler leaves and sweeter flavor are seen as less refined than Genovese. Sharp-tongued basil fans will notice its stronger hints of anise or cinnamon.

Beyond the standard green types common in North America, there are red and purple, citrus, Asian or Thai, and lettuce-leaf basils, each with its own color, flavor and culinary uses.

Disease Resistance

For more, see our tech sheets on preventing basil downy mildew and basil pests and diseases. Read about how breeders are developing better organic basil in this interview: Prospera^® downy mildew–resistant basil • a breeding breakthrough.

Basil's two most common diseases are basil downy mildew (DM), caused by a water mold, and Fusarium wilt (F), caused by a fungus. Resistant varieties can help where disease pressure is high.

• Newer downy mildew–resistant (DMR) basils offer stronger resistance than first-generation varieties. Still, the pathogen evolves quickly and different strains (races) have turned up in different regions, so try a few varieties to see which do best where you are.
• An interview with people who deal with basil downy mildew firsthand covers variety development, grower experience, and monitoring, reporting and management: Prospera^® downy mildew–resistant basil • a breeding breakthrough.
• To learn how to identify and prevent the disease, see our basil downy mildew prevention tech sheet.
• Look for seed lots tested for seedborne Fusarium, and consider Fusarium-resistant basil varieties.