How I Grow Black Beauty Eggplants from Seed (Beginners Guide)

Eggplants, or aubergines as they are also known, are one of my go-to hearty home garden vegetables. 

Black Beauty eggplants produce large purple to black fruits. The pant is sturdy with strong, broad leaves.

Start eggplant seeds indoors six weeks before the last expected frost. Transplant outdoors in full sun when the soil temperature reaches a minimum of 15 degrees C / 60 degrees F. Top plants when they reach 25 cm / 10 inches to develop 2-4 fruit-bearing side shoots and stronger, more compact plants. Harvest when the color is full, and the skin is shiny,

Blach Beauties are easy to grow and perfect for barbecues and warm salads, as a healthy filler in almost any oven dish, and of course, we all love eggplant parmesan and moussaka.

This article is a step-by-step guide to growing eggplant from seed to harvest.

Photos are taken in our garden, and I will start seeds in two different growing mediums: potting soil and vermiculite. More photos to come as the plants develop. I hope you bookmark the page and follow along.

This year, I have chosen to grow the “Black Beauty” or “Solanum melongema” variety of eggplant.

Quick takeaways: 

• Start seeds indoors six weeks or so before the last expected frost. 
• Cover the seeds and germinate around 25 deg Celsius / 77 deg Fahrenheit. 
• Remove the cover and place starter pots in a cooler area after sprouting.
• Eggplants can grow tall, top plant at 25 cm / 10 inches, and stake early for support.
• Do not move outdoors until the soil temperature is above 15 degrees Celsius / 60 degrees F
• Ensure you keep eggplants warm and watered for healthy growth. 
• Eggplants grow well outdoors after hardening off, ideal for greenhouses and warm spots in the garden.

From now on, I will write eggplant as it is shorter and easier to spell than aubergine. Find seed starting tools and equipment in the Seed starting section of "What we use and feel good about recommending". 

A step-by-step guide to growing eggplants from seed

1. Starting eggplants from seed

Materials needed: 

• Seeds
• Starter pots or seed starting trays (deeper is better)
• Growing medium (I am using potting soil and vermiculite)
• Heat mat or place on a warm surface
• Water

Fill your seed starter trays with your chosen growing medium. Plant 2-3 seeds in each starter pot or cell. 

Seed packets often write the recommended planting depth as 0.5 cm / 0.2 inches deep. For me, this means placing seeds on top of the growing medium and covering them.

When seeds are planted, mist them with water and cover the pot or seed starter tray with a translucent covering. 

Seed starter trays usually come with a dome with ventilation holes. If you are using plastic film, make holes in the plastic and watch out for condensation forming on the inside of the cover.

Keep your chosen growing medium moist, not soaking wet. I like to use a combination of misting with a spray bottle and bottom watering.

I have never found it necessary to soak fresh eggplant seeds before planting. But if I am working with last year's seeds or seeds of unknown quality, I would pre-soak in water overnight before planting.

Depending on the temperature, your seeds will germinate in 5-7 days, but it could also take 2-3 weeks. The ideal seed germination temperature is around 25 deg C / 77 deg F. Cooler temperatures mean slower germination and avoid temperatures below 18 deg C / 64 deg F.

Three tips:

1. I start 30+ plants and place half at the ideal germination temperature and the other half in a cooler spot. This way, I can start all seeds simultaneously but will have two different batches to transplant later.
2. Deep seed starter trays are great for eggplants as they promote healthy root development, and you do not have to put them up as early. 
3. It is perfectly fine to develop more than one seedling per starter pot. I do it all the time, and it is a great space saver.

I think eggplants are great, but they are not a delicious vegetable. And I read it everywhere, "Eggplants are delicious, ...". I don't think so. Tomatoes are delicious. They can be eaten off the vine, used for salads, or added to any warm dish - always delicious. This is not true for eggplants. What makes eggplants great is their ability to absorb flavor while being a meaty and hearty vegetable. 

2. Eggplant first leaves sprouting and caring for the seedlings

When I see the first leaves, I remove the cover and move the young seedlings to a cooler spot, 18-21 deg C / 64-70 deg F, with good access to light.

The seedlings started in vermiculite are given half the dosage of liquid fertilizer as soon as I see the first leaves.

I use full spectrum grow lights on 18 hours on / 8 hours off cycle. If you use a sunny window sill, you want 6-8 hours of natural sunlight. And do take care not to burn the seedlings, as it can get boiling behind a window, even in early spring.

But what if three seeds germinate in one cell? A happy problem and you have two options:

1. Thinning the weaker seedlings or, as I do, 
2. Allow more than one seedling to develop in each cell.

It is OK to let more than one seedling grow and develop in a single pot or cell. Depending on the cell or pot size, I move the seedlings to individual pots when they reach 8-15 cm / 3-6 inches.

Here in zone 7, where I garden, I often have to keep my eggplants indoors for a while. It takes time, and on a slow year like 2023, I am still waiting for a minimum outdoor temperature to warm up.

You may have read that you should wait for a temperature of at least 21 deg Celsius / 70 deg Fahrenheit before moving your eggplants outdoors. My advice is to focus on the soil tempereature. 

Here in zone 7, the day’s top temperature is far less important than the lowest night-time temperature. We often have hot days but cold nights in early spring with close-to-freezing night-time temperatures. Trust me, keep an eye on the soil temperature instead.

3. Potting up the eggplant seedlings

I recently made a quick head-cam video on potting up eggplant seedlings growing in the same pot or cell. I hope the video can show that potting up is a straightforward process and nothing that should be feared.

When to pot up?

Pot up the seedlings when you see roots at the bottom of the seed starter cells or when the cell is too crowded. Ideally, pot up to a deep nursery pot to facilitate root development.

How often should I pot-up?

Potting up your seedlings is a process and not a one-time event. Increasing the pot size gradually is a great way to save space and makes it easier to control soil moisture.

Why should I pot-up?

I can give you three reasons why you should gradually increase the pot size and pot up your eggplants more than once.

1. Potting up to deep nursery pots gives the root system room to grow strong. 
2. You can stabilize leggy seedlings by planting them deeper than they were growing. Do not pot up deeper than you must; you will not get root growth from the stem like with tomatoes.
3. Gradually increasing the nursery pot size means using less soil and less space. You can fit more plants in your allocated space, and less soil makes it easier to control soil moisture. 

4. Hardening off and moving outdoors

Spend a good week hardening off your eggplants before moving them outdoors. Do take your time to do this right. Start with one hour and then gradually increase the exposure to the outdoor climate. Avoid any exposure to direct sunlight for the first 3 days.

You want well-draining, healthy, and fertile soil as with all vegetables. If your soil is poor, use organic soil amendments to improve the soil in early spring. 

Do not move your eggplant seedlings outdoors until the minimum soil temperature is above 15 deg Celsius / 60 degrees Fahrenheit. If the soil is too cold, your eggplants will not grow - and if you are unlucky, they will start developing white leaves that turn brown and then wither and die.

When you have hardened them off, find a warm spot with full sunlight in your garden. Eggplants do like warm weather. As with tomatoes, you want a minimum of 6-8 hours of direct sunlight, ideally split between morning and afternoon sun. 

Plant the seedlings at least 50 cm / 20 inches apart and maintain the same minimum distance between rows if applicable. 

Water thoroughly and mulch around the eggplants. Using straw, hay, or wood chips works great to prevent weeds and creates a barrier between soil and plant. Be generous where 8 cm / 3 inches is better than 3 cm /1 inch.

Eggplants do great in grow bags, containers, and raised garden beds. The soil in raised garden beds warms up quicker in spring, making them a great alternative in cooler climates.

Grow bags and containers should be a minimum of 20 liters / 5 gallons to support one eggplant. But if you can, go deep; I prefer using grow bags that are 50 cm / 20 inches deep.

5. Support and top your eggplants

Eggplants can grow tall, and we know they will carry heavy fruits or berries to be botanically accurate. 

Yes, much like tomatoes, eggplants are fruits or berries as they contain edible seeds. 

Tall plants (60 – 80 cm / 2-3 ft) with heavy fruits can be tricky to support for any home gardener.

For me, I sometimes perform this step indoors, waiting for the weather to warm up. 

From experience, I face this challenge with a two-pronged action plan.

1. Get the support, stakes, or cages in place before the eggplant needs it
2. Top the plant when it reaches 25 cm / 10 inches 

Getting the support in place early is more straightforward and better for the plant, the same as for supporting tomato plants. 

With eggplants, I often wait to implement support after topping the plant.

Topping the plant will give you 2-4 fruit-bearing side shoots and a bushier and more compact plant.

6. Watering and fertilizing eggplants

Eggplants like full sun, warm weather, and lots of water. But do not fall into the trap of constantly watering daily.

Watering a little bit daily will cause the roots to grow shallow, and your plant will be more susceptible to dry outs and poor growth. 

Instead, water a lot (3-5 cm / 1-2 inches) once or twice weekly. Your eggplant will develop an extensive root system, and the roots will grow deep like you want. 

During the height of summer, you may have to water more often, maybe even daily, morning or evening.

If you have grown tomatoes before, you know how to fertilize your eggplants. If not, just remember to fertilize regularly (weekly) throughout the growing season. Dial back the nitrogen as the plant starts to fruit. Regularly adding compost will be enough if you do not want to purchase organic liquid fertilizers. 

But consider using a liquid fertilizer if you want to give your eggplants a quick boost.

7. Caring for eggplants and common pests

Row covers are great for many vegetables, including kale, leafy greens, and eggplants. 

Row covers protect against cold temperatures but also against pests and harmful insects. Simply cover your plants, fix the sides, and keep the cover in place except when watering. 

Eggplants are by no means immune to pests and harmful insects [1]. Common pests and diseases include aphids, stink bugs, whiteflies, colorado potato beetles, flea beetles, hornworms, and spider mites.

In our garden, we have mainly encountered aphids, leafhoppers, flea beetles, snails, and white flies.

Apart from using row covers, we plant marigolds and allow some of our herbs to flower to attract wasps and flies that will feast on pests and harmful insects.

We mulch with straw to create a layer between the soil and the plant to prevent soilborne diseases. We always water the base of the plants to prevent leaves from getting wet and attracting fungal diseases.  

Manual inspection and beer traps serve as a defense against snails, slugs, and sometimes caterpillars. Flea beetles are black and pop against the green leaves and are easy to spot and get rid of by hand if detected early.

If needed, we use a Neem oil-water solution to get severe infections under control. Neem oil is not as effective as some other commercial products, but it is organic and works after a couple of applications. 

8. Harvesting eggplants

Finally, harvest time; the trick is not to wait too long. If you harvest late, the eggplant may taste bitter, and the skin gets tough.

Wait for the right color and that shiny surface to pop, then cut the stem using sharp garden scissors. 

I harvest both smaller and larger-sized eggplants. Larger eggplants are great for stuffed eggplants and eggplant Parmesan. Smaller fruits are perfect to slice; drizzle them with olive oil and season with sea salt before you cook them in a pan.

Eggplants are great to use directly but can be kept in the refrigerator for up to 2 weeks. 

Helpful resources:

[1] https://hgic.clemson.edu/factsheet/eggplant-insect-pests-diseases/