Growing Eggplant Hydroponically: A Complete Tower Garden Guide

Choosing an Eggplant Variety for Hydroponics

You can grow many types of eggplant hydroponically, but they aren't all equally convenient in a vertical system. Think about both the mature size of the plant and the size and weight of the fruit.

Starting Eggplant From Seed

Plant 1 eggplant seed per rockwool cube. Eggplant likes warmth right from the beginning, so keep the rockwool evenly moist and in warm conditions while the seed germinates.

Once the seedling emerges, give it plenty of light so it develops strong, sturdy growth rather than stretching toward the light.

Eggplant generally develops more slowly than fast-growing crops such as lettuce or cucumbers, so don't worry if other seedlings started at the same time seem to race ahead.

For more detailed seed-starting information, including how seed counts vary by crop, see our guide to how many seeds to plant in rockwool and our Seeds & Seedlings Guide.

The photo above shows 12 young eggplant plants growing in a Tower at four weeks from seed. Keep in mind that young plants take up far less room than mature, fruiting eggplants. Plan your final Tower layout around the size the plants will become, not how small they are when first planted.

Where Should Eggplant Go in a Tower Garden?

Eggplant eventually becomes a fairly substantial plant, so placement matters. Give it enough open space for the leaves and branches to spread without completely shading smaller crops.

As the plant develops fruit, you'll also need easy access for pollinating, supporting branches and harvesting. Avoid squeezing a large eggplant plant between other vigorous fruiting crops where everything will compete for the same physical space.

If you're mixing crops in one Tower, use the smaller spaces around eggplant for crops that won't compete heavily with it as they mature.

How Much Light Does Eggplant Need?

Eggplant is a fruiting crop and needs considerably more light than leafy greens and many herbs.

Outdoors, place your Tower where the eggplant will receive plenty of direct sun. Indoors, plan on approximately 14–16 hours of grow light each day, followed by complete darkness overnight.

With Tower Garden grow lights, keep the lights roughly 6–8 inches from the top of the plants as they grow. Don't forget that an eggplant plant can become much wider and taller than it was when you first positioned your indoor Tower.

For more information, see our Tower Garden Light Guide.

What Temperature Does Eggplant Like?

Eggplant loves warm weather. Cool conditions can slow growth considerably, so don't treat it like lettuce or other cool-season crops.

If you're growing outside, wait until conditions are consistently warm. Indoors, a normal warm household environment is generally much easier for eggplant than a cold porch, garage or other space where nighttime temperatures drop significantly.

Water and Nutrients for Eggplant

Eggplant is a larger fruiting crop, so once the plant is established it needs consistent water and nutrition to support both vegetative growth and fruit production.

For an established Tower Garden, our standard Mineral Blend rate is 20 mL of Mineral Blend A and 20 mL of Mineral Blend B per gallon of water. For young seedlings, use approximately half strength — 10 mL of A and 10 mL of B per gallon.

During very hot weather, we may reduce nutrient strength further, sometimes to half or even quarter strength depending on conditions.

Keep the Tower's pH between approximately 5.5 and 6.5, and check the reservoir regularly. A mature eggplant plant can use substantially more water than it did when it was young.

You do not need a separate nutrient solution just because you're growing eggplant alongside other crops in the same Tower.

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

Does Eggplant Need Pollination?

Eggplant flowers contain both male and female reproductive parts, so you don't need a separate male and female plant. However, the pollen still needs to move within the flower for good fruit set.

Outdoors, wind and pollinating insects often do much of this work for you. Indoors — or whenever flowers are blooming but fruit isn't developing — you may need to help.

A simple way to do this is to gently vibrate or tap the flower to help release the pollen. An electric toothbrush held against the flower stem for a moment can also provide the vibration needed to move pollen.

Does Eggplant Need Pruning or Support?

Usually, yes — especially once the plant begins carrying fruit.

Eggplant branches can become heavy and may break under the weight of developing fruit. Compact varieties such as Patio Baby are easier to manage, while larger plants and heavier-fruited varieties need more attention.

Use a Tower Garden cage, stakes or another support system to keep heavily loaded branches from bending or breaking. It's much easier to establish support before the plant is loaded with fruit than to try to rescue branches afterward.

You can also remove damaged, unhealthy or badly positioned growth as needed. Avoid aggressively stripping healthy leaves, since the plant needs that leaf area to produce energy and shade developing fruit.

Can You Grow Eggplant Indoors?

Yes. Eggplant can be grown indoors hydroponically, but variety choice and lighting become particularly important.

Patio Baby is the variety we'd look at first for an indoor Tower because the plant stays more compact and produces smaller fruit.

You'll need strong grow lights for 14–16 hours per day, enough vertical and horizontal space for the mature plant, and you'll probably need to help with pollination. Support may still be needed as fruit develops.

If you're planning an indoor Tower with several fruiting crops, don't fill every opening with tomatoes, peppers, cucumbers and eggplants. Those tiny seedlings don't stay tiny for long.

For more ideas, see our guide to the best compact plants for indoor Tower Gardens.

Common Eggplant Growing Problems

Flowers but no fruit

Check pollination first, particularly indoors. Insufficient light, temperature extremes or a stressed plant can also interfere with fruit set.

Slow growth

Eggplant naturally takes longer to get going than many leafy crops, but very slow growth can also point to cool temperatures, insufficient light, nutrient issues, incorrect pH or root problems.

Yellowing leaves

Don't automatically assume yellow leaves mean the plant needs more nutrients. Check pH, reservoir level, nutrient strength, root condition, temperature and the pattern of yellowing before making adjustments.

Flowers dropping

A few dropped flowers aren't necessarily a problem. If most flowers are dropping, look at temperature, water availability, light and overall plant stress.

Branches bending or breaking

Fruit can become surprisingly heavy. Add support before branches are under enough strain to snap.

Common Eggplant Pests and Diseases

Eggplant belongs to the same plant family as tomatoes and peppers, and some of the same pests can show up on all three.

Aphids

Check tender new growth and the undersides of leaves for clusters of small insects. Aphids can multiply quickly, so catching them early makes control much easier.

Flea Beetles

Flea beetles are particularly associated with eggplant. Their feeding creates many tiny holes in the leaves, and young plants can be hit especially hard.

Spider Mites

Spider mites thrive in hot, dry conditions. Look for fine stippling or discoloration on leaves and, with heavier infestations, very fine webbing.

Whiteflies

Whiteflies usually gather on the undersides of leaves and may fly up when the plant is disturbed. Sticky traps can help you monitor flying pest populations.

Inspect your plants regularly rather than waiting until damage is severe. Pay particular attention to the undersides of leaves and new growth.

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

When Is Eggplant Ready to Harvest?

One of the most common mistakes with eggplant is leaving the fruit on the plant too long because you're waiting for it to get bigger.

Harvest eggplant while the fruit is still firm and the skin looks smooth and glossy. Once fruit becomes dull, very hard or overmature, eating quality begins to decline and the seeds inside become more developed.

Fruit size varies enormously by variety. A Patio Baby eggplant should not be judged by the expected size of a traditional full-size eggplant, and long Oriental types have a completely different shape.

Use clean pruning shears or scissors to cut the fruit from the plant rather than pulling or twisting it from the branch. Eggplant stems can be tough, and pulling the fruit can damage the plant.

Is Eggplant a Good Crop for a Tower Garden?

Yes — particularly if you enjoy growing fruiting crops and are willing to give the plant enough space.

For indoor growers or anyone working with limited room, a compact variety such as Patio Baby is an excellent place to start. Oriental types are another useful option because their long, slender fruit is generally easier to manage than very large, heavy eggplants.

The biggest things to remember are simple: give eggplant warmth, strong light, enough room, consistent water and nutrients, help with pollination when necessary, and support the plant as the fruit develops.

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