Growing Basil Hydroponically: A Complete Tower Garden Guide

Best Basil Varieties for Hydroponic Growing

One of the fun things about growing basil is that you're definitely not limited to the standard basil you see in the grocery store. There are many varieties with different flavors, leaf shapes and growing habits.

• Genovese Basil – The classic pesto basil, with large, fragrant leaves and that familiar sweet basil flavor.
• Sweet Basil – An excellent all-purpose basil for sauces, salads, pasta and everyday cooking.
• Thai Basil – Has a distinctive anise or licorice-like flavor and is excellent for curries, stir-fries and other Asian dishes.
• Lemon Basil – Adds a citrusy flavor that works especially well in salads, seafood dishes and drinks.
• Purple Basil – Beautiful dark foliage makes it as ornamental as it is edible.
• Holy Basil (Tulsi) – An aromatic basil commonly grown for herbal teas and traditional uses.

Most basil varieties grow very well hydroponically, so choosing one usually comes down to what flavor you like and how you plan to use it.

Shop all basil seeds and seedlings →

Starting Basil from Seed

Basil is relatively easy to start from seed and usually germinates quickly under warm conditions.

We generally start 6–8 basil seeds per rockwool cube. Unlike larger fruiting crops such as tomatoes and peppers, basil can grow well as a small cluster, so you don't need to thin the cube down to one plant.

1. Place 6–8 basil seeds into each rockwool cube.
2. Keep the rockwool evenly moist while the seeds germinate, but don't leave it sitting in water.
3. Keep the seeds warm and provide good light as soon as they emerge.
4. Once the seedlings are established and have developed true leaves, they can be moved into the Tower Garden or another hydroponic system.

Basil often germinates in around 5–10 days, although temperature, variety and seed age can affect germination time.

For more information about how many seeds to plant for different crops, see our How Many Seeds Should I Plant? guide.

Where to Plant Basil in a Tower Garden

Basil doesn't require the heavy support that tomatoes, cucumbers and other fruiting crops do, which makes placement fairly flexible.

Give it enough space for good airflow and for the plant to spread as you prune it. A well-pruned basil plant can become much wider and bushier than the little seedling you originally put into the tower.

If you're growing basil alongside larger crops, think about what those plants will look like several weeks from now. Avoid putting basil where a large tomato, cucumber or other vigorous plant will eventually shade it.

How Much Light Does Basil Need?

Basil loves light. Outdoors, place it where it can receive plenty of sunlight. Indoors, good grow lights are one of the biggest factors in producing compact, bushy plants rather than tall, stretched ones.

For indoor Tower Gardens, we generally run grow lights for around 14–16 hours per day and give plants complete darkness overnight.

Keep the lights approximately 6–8 inches above the tops of the plants, adjusting them as the basil grows.

See our Tower Garden Light Guide for more help with indoor and outdoor lighting.

Best Temperature for Growing Basil

Basil is a warm-season herb. It generally grows fastest in warm weather and is much less happy when temperatures become cold.

Cool temperatures can slow growth, damage leaves and cause discoloration. Basil is also very sensitive to frost.

In very hot weather, watch the plants and the reservoir closely. High temperatures increase plant water use and can also increase stress, particularly when the nutrient solution becomes warm.

Here in Florida, basil can be a great warm-weather crop when many cool-season greens are struggling with the heat.

Water & Nutrients for Hydroponic Basil

Basil doesn't need a special basil fertilizer. It can grow right alongside other crops in the same Tower Garden using the standard Tower Garden Mineral Blend.

For established plants, the standard concentration is 20 mL of Mineral Blend A and 20 mL of Mineral Blend B per gallon of water.

For young seedlings, use approximately 10 mL of A and 10 mL of B per gallon. During very hot weather, reducing nutrient strength can help plants cope with heat stress. Depending on conditions, we may use half-strength or even quarter-strength nutrients.

Keep the reservoir topped up and maintain the water at approximately pH 5.5–6.5.

For more detail, see our Tower Garden Nutrients Guide and Tower Garden Water Guide.

How to Prune Basil for a Bushier Plant

If you want big, productive basil plants, don't be afraid to prune them. Regular pruning is one of the most important parts of growing basil.

Instead of continually picking individual leaves from the bottom of the plant, look for a pair of leaves with small new shoots forming where those leaves meet the stem. Cut the main stem just above that leaf pair.

The two small shoots below your cut can then develop into two branches. As those branches grow, you can repeat the process. That's how a tall single stem becomes a much fuller basil plant with many growing tips.

Regular harvesting effectively becomes regular pruning, which is one reason basil can become more productive the more often you use it.

How to Keep Basil From Flowering

Eventually, basil will try to flower. That's completely normal—the plant is attempting to reproduce.

If you're growing basil primarily for leaves, however, it's usually better to remove flower buds as they appear. Once a basil plant moves heavily into flowering and seed production, leaf production can slow and the flavor and texture of the leaves may change.

Pinch or cut the flowering stem back to just above a healthy set of leaves. This encourages the plant to branch and return more of its energy to vegetative growth.

If the plant has become very tall and has flowers everywhere, don't be afraid to give it a more substantial prune. As long as you're leaving healthy growth below your cuts, basil often responds with a flush of new branches.

Can You Grow Basil Indoors?

Absolutely. Basil is one of our favorite herbs for indoor hydroponic growing because it stays relatively compact, doesn't require pollination for leaf production, and responds well to frequent harvesting.

The biggest challenge indoors is usually light. A bright window may keep basil alive, but it may not provide enough light for the dense, vigorous growth most people are hoping for.

With appropriate grow lights, basil can be grown indoors throughout the year.

If you're planning an indoor Tower Garden, our Best Compact Plants for Indoor Tower Gardens guide can help you choose other crops to grow alongside it.

Common Problems When Growing Basil Hydroponically

Tall, Leggy Basil

If your basil has long stems with lots of space between the leaves, start by looking at light. Insufficient light can cause plants to stretch. Regular pruning is also important for encouraging branching instead of one tall central stem.

Yellow Basil Leaves

Yellow leaves don't have one single cause. Check the basics before making drastic changes: water quality, nutrient concentration, pH, reservoir temperature, root health and light.

Brown or Damaged Leaves

Leaf damage can result from environmental stress, pests, disease or physical damage. Look at where the damage appears and whether it's spreading rather than diagnosing a plant from one damaged leaf.

Basil Isn't Growing

Slow growth is often associated with cool temperatures, inadequate light, root problems or incorrect nutrient conditions. Basil normally grows quickly when it's warm, well lit and actively rooted.

Basil Keeps Flowering

Flowering is part of basil's natural life cycle, particularly as plants mature or experience stress. Remove flower buds and prune the stems back to healthy leaf nodes to encourage more leafy growth.

Common Basil Pests

Basil is generally easy to grow, but it isn't immune to pests. A few problems to watch for include:

• Aphids – Small sap-sucking insects that often gather on tender new growth and the undersides of leaves.
• Whiteflies – Tiny white insects that may fly up when the plant is disturbed.
• Spider mites – Very small pests that can cause stippling or discoloration and may produce fine webbing when populations become heavy.
• Caterpillars and other chewing insects – Look for holes in leaves and inspect the plant carefully for the culprit.

Inspect plants regularly, especially the undersides of leaves and new growth. Catching a pest problem early is much easier than dealing with a large infestation later.

For identification and treatment options, visit our Tower Garden Pests & Diseases Guide.

How to Harvest Basil

The best way to harvest basil is also the best way to prune it.

Instead of removing only individual leaves, cut stems just above a healthy pair of leaves. You'll get basil to use in the kitchen while encouraging the plant to produce additional branches.

Harvest regularly once the plant is established. Frequent harvesting helps prevent plants from becoming tall and woody and gives you a steady supply of tender new growth.

If you need a lot of basil at once, you can harvest a significant portion of a healthy plant—just avoid stripping it completely bare. Leave enough healthy foliage and growing points for it to recover.

What Can You Do With All That Basil?

This is one of the better problems to have. A happy hydroponic basil plant can produce far more than a few garnish-sized leaves.

Fresh basil is great in pasta sauces, salads, sandwiches, soups, curries, drinks and, of course, pesto.

Other easy ways to use a big basil harvest include Caprese salad, basil lemonade, infused water, homemade tomato sauce or simply chopping fresh leaves over tomatoes and mozzarella.

Is Basil a Good Hydroponic Crop?

Definitely. Basil grows quickly, doesn't need pollination or support, works well indoors or outdoors, and responds to harvesting by producing even more growth.

It's also a great crop for learning how pruning affects plant growth. Once you see one stem become two, then four, then eight, it becomes much easier to understand why regular harvesting can turn a small basil seedling into a big, bushy plant.

Whether you're filling an entire Tower Garden with herbs or simply tucking a few basil plants between other crops, basil earns its space.

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