16 Tips For Growing Eggplant in Raised Garden Beds
Are you thinking of growing eggplant in raised garden beds this season? Using raised beds for eggplant can be effective, but requires a bit of finesse. In this article, gardening expert and homesteader Merideth Cohrs walks through her top tips for bountiful eggplant yields from raised beds!
Eggplant – or aubergine as it’s called in many parts of the world – may not be as popular in American gardens as the tomato or pepper, but it should be! The ranges of sizes, shapes, and colors of this heat-loving vegetable are a testament to its popularity in places like India, Japan, and other parts of Southeast Asia. In fact, in Japan, eggplant is the third most important vegetable only after sweet potato and radish!
The question then becomes how do we grow eggplant in our home garden? Do eggplants grow well in a raised bed? The answer is yes! But, like growing any kind of veggie in raised beds, there are a few tricks of the trade you should know about for a truly bountiful harvest.
So, if you’ve decided to grow eggplant in raised beds this year, you’ve come to the right place! Let’s take a look at some top tips for a successful raised bed eggplant harvest to help you along the way this season!
Raised beds can be a gardener’s best friend in many cases. In general, raised beds are often more productive than planting directly in the ground because the soil is of high quality, it’s less compacted, it has better drainage, and it warms earlier in the spring.
You will also deal with fewer weeds and soil-borne diseases. Raised beds also look really beautiful and can add a nice touch of landscaping to your yard.
There are many different ways of building a raised bed in your garden. You can purchase pre-made solutions that you put together, build them yourself, or hire someone local to build a custom solution for your space.
Eggplant happens to be a vegetable that does really well in raised beds. I have grown them – along with many other vegetables – in raised beds for years with excellent results.
Since I garden in a small space, raised beds have been a lifesaver for me and have allowed me to grow and harvest much more than I would have been able to do in containers alone.
Tips For Growing in Raised Beds
There are many reasons why one would use a raised garden to grow eggplant. A longer growing season and ideal growing conditions are just two of them. Now that we know eggplants can benefit from growing in raised beds, let’s find out how to help them thrive in these elevated gardens.
There are quite a few options when it comes to raised beds. I have used them placed directly over existing soil as well as elevated wooden beds on my deck. The most important consideration is the type of material you choose to use.
Untreated wood is usually the first choice. Woods like cedar do exceptionally well because they won’t degrade in wet conditions. You can also use galvanized metal garden beds that have drainage holes in the bottom.
You want to avoid materials that can leach toxins into your soil. Remember, your cucumbers will uptake whatever is in the soil and water of your bed. Avoid DIY solutions that call for using railroad ties, treated wood, pallets, concrete blocks, tires, or any kind of painted wood. I am all for recycling and upcycling, but in this case, it’s a bad idea.
A good rule of thumb is to not make your raised bed wider than 4 feet. One of the benefits of raised beds is loose, well-aerated soil. If you step into the bed to reach your eggplants, you will compact the soil around your foot. You definitely don’t want this to happen.
Most people can reach about 2’ from either side of a raised bed, which is why we encourage a 4’ maximum width. If you are placing your bed near a fence, make your bed 2-3’ for the same reason.
Eggplants should be planted about 18-24 inches apart to allow proper growth. This also allows enough airflow between plants so that fungal diseases do not appear. With this spacing, you should be able to grow plenty of eggplants in a garden bed that’s less than 4 feet wide.
Soil Should Be at Least 12 Inches Deep
Plants have a root system that grows down into the soil. This root system can grow many inches, depending on the vegetable or plant growing. Most raised beds provide you with enough room for a soil depth of 12 inches.
Eggplants will do fine in this soil depth, but they really thrive with 18 inches of room. If you can make your raised bed a little deeper, your eggplants will thank you for it! This extra space will allow enough room for the roots to grow.
Invest in High Quality Soil
After building your raised bed, it’s time to fill it with organically rich, fertile, and well-draining soil. To help prepare your raised bed, start with rich, loamy, outdoor potting soil. About a month prior to planting, amend that soil with compost by gently digging it in.
I love using my own homemade compost (I’m a big proponent of vermiculture!), but you can also use store-bought compost for this. Look for organic compost with worm castings for great results.
Eggplants prefer slightly acidic soil – ideally with a pH between 5.8 and 6.5. It’s a good idea to test your soil prior to planting to see where things naturally are. If you find your soil too alkaline, add a soil acidifier at the same time as your compost.
Choose a Variety You’ll Eat
For most of us, eggplant has always equated to the large purple bell-shaped fruit in the grocery store. As a kid, I never had eggplant and certainly didn’t know what to do with it if I had one! It wasn’t until I joined a CSA many years ago that I was exposed to eggplant in a tangible way.
I learned all about how to make baba ganoush (still one of my favorite ways to enjoy eggplant!), moussaka, and eggplant parmesan. I also add them to stir-fries and curry all summer long.
If I have a true abundance in a season, I’ll dehydrate them and add the eggplant powder to pasta sauces. It adds an amazing depth of flavor without altering the core sauce.
Since the sky’s the limit in the kitchen, allow yourself to have a little fun in your garden as well! Let’s take a look at the most popular eggplant types so you can grow a variety that gets you excited. If you’re choosing to grow your plants from seed, you can find examples of all of these at any online seed retailer.
The great news about eggplant is that any of these varieties will thrive in a raised bed. you simply cannot go wrong with whichever type you choose!
Grow From Seed or Purchase Starts
Since eggplants have a longer growing season than many other summer vegetables – around 120 days or longer depending on the variety – you’ll need to start your seeds indoors or purchase starts from your local nursery or garden center.
Unless you live in a very warm climate, sowing seeds directly in the ground won’t give your plant enough time to mature, flower, and set fruit.
Personally, I grow all my vegetables from seed each year. This allows me to choose seeds that I know grow well in my area, have great flavor, and offer heirloom, organic and non-GMO options. I can also be confident that my seedlings are healthy, vigorous, and well hardened off prior to transplanting outside in my beds.
Burpee, Baker, and Johnny Seeds are great places to start looking, but there are a lot of options out there. Be sure to read reviews, and see how other gardeners have fared with the varieties you’re interested in. Gardeners are a friendly lot and typically want to share information whenever they can. Pay attention to them especially if you’re a newer gardener!
Remember, that certain eggplant varieties grow better in hot arid climates, while others thrive anywhere. Either way, plan to start your seeds indoors approximately 8-12 weeks before the last frost date in your area.
I recommend buying vegetable starts from a local nursery or farmer’s market over a big-box store whenever possible. Seedlings there are typically sourced from local or regional growers, are grown organically, and are well cared for.
Often, starts at your local big-box garden center are treated heavily with pesticides and they are shipped quite a distance from non-organic growers. Some retailers have phased out neonic pesticides (which kill bees and other pollinators), but not all.
Regardless of where you buy your seedlings, take the time and choose the healthiest ones. The plant should have dark green leaves, be well-branched, shouldn’t be leggy (meaning it’s too tall for the stem to support it well), and shouldn’t have flowers yet. Avoid plants with yellowing leaves, strange growth patterns, and flowers.
Plant at the Right Time
Eggplants are a warm-season crop, meaning they shouldn’t be planted while there is any chance of frost. Like tomatoes and peppers, it’s better to wait until nighttime temperatures are consistently above 55 degrees (they actually thrive in soil temps above 70 degrees). This will ensure that soil temperatures are warm enough to keep your eggplants happy.
The good news is that the soil in raised beds is typically warmer than the soil in the ground. This means that you can likely plant your eggplants a little earlier in the season. If you do plant early in the season, install a floating row cover on your raised bed to keep your young seedlings protected.
Floating row covers are incredibly easy to use. They’ll not only keep your eggplants warmer, but they will also protect them from early attacks from pests like the dreaded flea beetle.
Practice Regular Crop Rotation
Even in the home garden, crop rotation is incredibly important. In a small space, this can be difficult to manage especially if you only have one or two raised beds to work with. But the importance cannot be overstated.
Certain pests and diseases hit members of the nightshade family (tomatoes, peppers, eggplant, etc) with equal opportunity. If you plant your eggplant in the same location as your previous season’s tomatoes, you’re at increased risk of soil-borne disease or overwintering pests.
Ideally, give your soil a year off between nightshade plantings. If you have multiple beds, planning a simple crop rotation should be fine.
If you have a single raised bed, this may be a challenge for you. In this instance, I recommend using a large container to plant your eggplant in the off years. Eggplants do really great in containers as well!
The amount of fruit your eggplants produce has a direct correlation with the amount of sun they receive. Eggplants need to be planted in an area that receives full sun, meaning at least 6 hours of direct sun each day. Ideally, they’d like 8-10 hours of sun for maximum fruit production.
If you’re not sure how much sun your space receives, take a few days to actively measure it. Note when the sun first reaches a particular area, if it’s ever shaded by tall trees or other buildings, and when it leaves for the day.
While your eggplants will be fine with western or eastern exposure, southern exposure is really the gold standard. Southern exposure provides your plants with gentle morning and early afternoon sun while protecting them from the harshest afternoon rays.
Mulch is incredibly important in your garden but is often overlooked. Mulch protects against excessive heat, aids moisture retention in the soil, prevents water splashing back (which can spread fungal disease from the soil), and discourages weeds.
In fact, you probably won’t have too many issues with weeds at all in your raised bed if you mulch well!
You can use a lot of things as mulch including organic material you may have laying around in your yard. Straw, wood chips, crushed leaves, and even crushed eggshells can offer the soil that extra layer of protection. The possibilities are almost endless!
Your local nursery or garden center will also have plenty of mulch options available if you don’t have any already. No matter what type of mulch you choose, aim to apply a layer 2-3” thick for maximum benefit.
Personally, I love using coconut coir for the raised beds in my vegetable garden. I get large blocks of it early in the season and add it to my beds as I finish planting.
There are a lot of benefits to using coir including sustainability and renewability (coir is a natural waste product resulting from processing coconuts!). But for raised beds, there are a few extra perks.
Coir mulch holds 30% more water than similar peat-based mulches. It absorbs water easily and drains slowly back into the soil. In raised beds, this is especially important since the soil dries out much quicker than soil in the ground.
Coir is rich in carbon and will add nutrients back into the soil as it decomposes.
One of the things you will notice with raised beds is that your soil will compact each season. This is natural as things settle and organic material decomposes. The problem with this is that compacted soil isn’t a great environment for growing root systems. Digging in your coir mulch at the end of the season will actually help lighten the soil, improve air circulation, and allow for freer movement of nutrients.
Stake Your Eggplant
You may not realize that eggplants need support until their heavy fruit starts to mature. A single plant produces anywhere from 4-20 mature eggplants depending on the variety (smaller varieties produce more fruit than larger ones).
Just like other members of the nightshade family like peppers and tomatoes, your eggplants will produce a higher yield if they are properly supported.
Tomato cages, stakes, or both are commonly used to stake eggplants. It’s a good idea to install these at the time of transplanting so the plant’s root structure isn’t impacted later on.
I typically use tomato cages and bamboo poles since I am able to reuse these items every season. They’re relatively inexpensive and caging can actually help contain your plants a bit in the raised bed.
Eggplant fruits have a high water content, so it shouldn’t be a surprise that the plants are pretty thirsty. Eggplant will thrive when the soil is consistently moist but not soaking wet. Think of the amount of wetness in a squeezed-out sponge and you’ll be just about right.
The best way to determine if your eggplants need water is to stick your finger in the dirt (below the mulch) about 2-3 inches. If the soil is dry, it’s time to water. If it’s still moist, you can give it another day.
Keep in mind you will need to water more frequently than if the eggplants were planted in the ground. This is because water has more space to drain from.
Water slowly and deeply.
Most plants don’t like a deluge of water and eggplants are no different. Think about the difference between taking a nice sip of water from glass vs someone opening a fire hydrant for you. In an ideal situation, you can set up a drip system before planting. This will deliver water to your plants in a consistent and manageable way.
If you don’t have a drip installed, don’t worry. You can simply turn your hose on the lowest setting and just let it slowly stream into the soil. It may take a little longer than you want it to, but you’ll be happy about the end results.
Water the roots, not the leaves.
A common mistake with new gardeners is to water the top of the plant rather than the soil underneath. This can actually cause a lot of problems with your eggplant including the spread of fungal disease (caused by wet soil splashing on the underside of the lower leaves), powdery mildew, leaf burn, and attracting pests.
Always aim to slowly water the soil either with a drip system or low flow hose. Always try to water your eggplants in the morning and not during the heat of the day!
I know it sounds counterintuitive, but you’ll want to pinch off the first set of flowers when they emerge. In the beginning stages, it’s important that the plant uses its energy to develop multiple fruiting branches and foliage before turning to flower and fruit production.
If a young plant blooms flowers and sets fruit too early, the yield will be disappointing. The gorgeous purple flowers the plants produce may be the most beautiful of any vegetable in the garden. However, you must wait to enjoy them until your plant is more mature!
If you have added quality compost prior to planting, you won’t need to add additional fertilizer when you transplant your seedlings into the raised bed. If you skipped that step (or forgot!), now is the time to add a balanced eggplant-friendly fertilizer.
Eggplant, like most fruiting vegetables, needs a particular balance of macronutrients like nitrogen, phosphorus, and potassium. They also need micronutrients like magnesium, calcium, and zinc.
Nitrogen promotes foliage growth and fruit-producing branches. A fertilizer with too much nitrogen will result in a plant with too many leaves and not enough flowers or fruit.
Phosphorus is crucial for the growth and development of the root system as well as fruit. Potassium helps the plant grow rapidly and produce flowers and fruit.
Eggplants may need more of certain nutrients at different stages of their life cycle. When first planting eggplant, a balanced slow-release fertilizer is an ideal choice. Once the plant reaches maturity and starts to flower, switch to a fertilizer higher in phosphorus and potassium (like a 5-10-10) and apply every 2 weeks.
Check for Pests and Diseases Daily
Raised beds are like mini-ecosystems in your garden. The problems experienced will largely depend on what you have planted with your eggplants.
Be prepared to protect against pests like aphids, beetles, hornworms, and spider mites if there are other members of the nightshade family planted nearby. Many pests love to feast on nightshades and they can easily migrate from plant to plant.
No matter what you decide to plant in your raised bed this season, plant to spend time in your garden each day even if it’s only for a little bit.
Take a look at your eggplants, check under the leaves for signs of small pests, look for signs of stress or damage, and always be on the lookout for bigger issues like bacterial leaf wilt that can destroy your plant and migrate to the next.
Flea beetles, which chew many many many tiny holes in leaves, are by far the biggest pest threat to your eggplants. I have experienced these tiny infuriating pests every year I have planted eggplant, but there are ways you can help protect your plants!
Going back to one of my earlier tips, don’t plant your seedlings outdoors too early. When plants are roughly a foot or more off the ground, flea beetles seem to have a harder time finding them.
When they’re small, however, the seedlings seem to attract the beetles like magnets. Alternatively, you can keep your young plants covered with row covers until they are tall enough to confound the flea beetles (this is your best defense!).
If you do find yourself dealing with an infestation, you can try to dust the area with diatomaceous earth. Be very careful with this, however, as it can affect pollinators as well. I choose not to use this particular fix once I see pollinators in my garden.
Another option is to use sticky tape or paper and place this around your young eggplants. Flea beetles hop around (they’re not easy to get rid of like aphids) and some may get caught on the paper as they try to hop up to the leaves.
Help Pollinate Flowers
While eggplants are self-pollinating, you can help the process along to maximize fruit production. This will be especially important if you continue to use row or floating covers on your raised bed for pest prevention.
It may seem silly at first, but all you have to do is gently shake your plant or tap flowering branches to help move the pollen. If you have done a good job attracting pollinators to the space, they can help too, but only if the plants are uncovered.
High temperature and high humidity can all have a negative impact on the pollination process. Humidity can cause pollen to become sticky and prevent it from falling off the flowers. In dry regions, the pollen can actually dry out and fail to stick to the female parts of the flowers. By helping the plant self-pollinate, you’ll improve your eggplant yield this season!
Utilize Companion Plants
Companion planting is an incredible way to maximize a small space. So even if you only have access to one or two raised beds this year, you can fit a lot in there! Let’s talk about the best aromatic herbs, veggies, and flowers to companion plant with your eggplants.
Flowers are incredibly important to encourage pollinators to check out your eggplants. Even though eggplants are self-pollinating, natural pollinators really increase the efficiency of the process. Flowers also do a great job of attracting predatory insects that would love to help you out with any pest problems you may experience.
Planting flowers natural to your area can really help this as well. But if you’re looking for some tried and true flower helpers, check out marigolds and nasturtiums.
French marigolds especially act as a trap plant and will attract pests like whiteflies and aphids away from your eggplants. You’ll need to plant these several weeks ahead of your eggplant for them to be large enough to make a difference.
Nasturtiums attract pollinators, predatory insects, and act as a trap plant specifically for aphids. Trailing nasturtium will also act as a wonderful ground cover to help protect against weeds.
Most fragrant herbs – peppermint, dill, oregano, parsley – help deter pests from your eggplants. Since space is at a premium in raised beds, I recommend choosing only one or two of these to plant nearby. Here are some options.
This is one of my all time favorite companion plants. However, it’s not often found at local nurseries (I have to order seeds). Borage is a flowering herb that pollinators and predatory insects swarm to. This will go a long way toward both natural pest control and natural pollination once your cucumber flowers start to bloom. Borage can get kind of large if left unchecked, so just keep an eye on it as it grows.
Another one of my favorites, the sulfur compounds deter aphids and come back year after year. These are also a great addition to cooking whenever a light onion flavor is needed.
This is a strong smelling herb with an established reputation for repelling pests. Keep in mind that you will need to cut back your oregano in a raised bed since the plant is a fast growing perennial.
Mints like peppermint or spearmint can be a great help in deterring the hated flea beetle. Mint is an invasive herb, however, so if you plant it in your raised beds, be prepared to heavily prune it back as it spreads.
Peas, beans, and lentils all contribute critical nitrogen to your raised bed. This directly benefits nearby plants – especially heavy-feeding eggplants – by providing them with vital nutrients.
Legumes have a symbiotic relationship with certain soil-dwelling bacteria. The bacteria take nitrogen from the air in the soil and feed it to the roots of the legumes. In exchange, the plant provides carbohydrates to the bacteria.
Any of the nitrogen not used by the legume is released into the nearby soil through the roots. This is how legumes ‘fix’ nitrogen in the soil.
Heat tolerant spinach and lettuces can be good companions to eggplant as well. Leafy greens will have a chance to grow in the summer if they are kept in shady, cooler conditions. In return, they act as ground cover around your eggplants, which will keep weeds away.
Kohlrabi is actually a pretty great companion veggie as well and one that is really fun and easy to grow. Kohlrabi can help deter pests like aphids and flea beetles.
You can certainly do this, but be extra vigilant with pest control. Most pests like aphids, flea beetles, and spider mites can easily hop between plants and soon your entire bed will be infested.
Now that you’ve done all the things to help your eggplant grow and thrive in your raised beds, it’s time to harvest! This part is easy compared to the rest of the work put into growing these delicious vegetables.
Pick your eggplants when the skin takes on a high glossy shine. You can also test the skin to see if the fruit is ripe. Press the skin with your finger. If the indentation doesn’t immediately spring back, that fruit is ready for harvest! If it does spring back quickly, give it a few more days to mature.
The great thing about using a raised bed is that harvesting your eggplant is a breeze! Simply clip the fruit off the plant with pruning shears, keeping the cap and about an inch of stem intact.
Personally, I love picking eggplant when they are on the young side – about ⅔ of their mature size. This ensures a lovely texture and sweetness that can sometimes be lost in overly ripe fruits. However, the best time to harvest is up to you and how you prefer to eat them!
You are now well prepared to successfully plant, grow, and harvest eggplant out of your raised bed this season. These popular vegetables are the garden gift that keep on giving each season! Enjoy those beautiful purple veggies and all the incredible dishes you can create with your homegrown eggplant.