Sea Purslane: The Salt-Loving Edible Plant That Thrives in Aquaponics
Discover sea purslane, a hardy tropical edible that can handle salty conditions, grow in water-based systems and provide a fresh, succulent harvest straight from your backyard.
When it comes to growing your own food in the tropics, finding plants that can handle heat, humidity and challenging growing conditions is always a win. But what if you could grow a leafy green that naturally thrives in coastal environments, tolerates salt and can do exceptionally well in the right aquaponics setup?
Meet sea purslane (Sesuvium portulacastrum).
This creeping, succulent plant is found in tropical and subtropical coastal regions around the world. While it might not be as familiar as lettuce, basil or spinach, sea purslane is an interesting edible plant with plenty of potential for Australian backyard gardeners, particularly those experimenting with aquaponics and alternative food crops.
Let's look at what makes this plant special, how to grow it successfully and how to put it to use in the kitchen.
What is sea purslane?
Sea purslane is a low-growing, spreading plant with fleshy green leaves, succulent stems and small pinkish-purple flowers. It naturally grows in places such as sandy coastlines, coastal wetlands and salty marshlands, where many conventional vegetables would struggle.
Its creeping growth habit makes it useful as a ground cover, while its succulent leaves give it a distinctive appearance.
But one of its most interesting characteristics is its ability to tolerate conditions that would damage many other edible plants.
Sea purslane is a halophyte
A halophyte is a plant that can tolerate and grow in salty environments. Some halophytes are specially adapted to cope with salt concentrations that would severely stress ordinary garden vegetables.
Sea purslane is a salt-tolerant halophyte. It can grow in saline soils and water, and research has shown that it can tolerate a wide range of salinity levels. It can also grow in non-saline conditions, meaning you don't need to live beside the ocean or add salt to your garden to grow it.
This is particularly interesting for gardeners exploring alternative crops, coastal food production and aquaponics.
Rather than treating salt as an automatic problem, sea purslane has adaptations that help it manage the stress associated with salty environments.
It's worth remembering, though, that salt tolerance doesn't mean unlimited salt tolerance. Excessive salinity can still inhibit growth, and the right conditions depend on the plant variety and growing environment.
Why sea purslane is worth growing in the tropics
Here in tropical Australia, we need plants that can cope with warm conditions and keep producing when the weather becomes challenging.
Sea purslane has several characteristics that make it worth considering:
- Heat tolerance: Its natural habitat includes warm tropical and subtropical coastal regions.
- Salt tolerance: It can cope with saline conditions that would stress many conventional vegetables.
- Succulent leaves: Its fleshy foliage stores water and helps it cope with periods of limited water availability.
- Spreading growth: Its creeping habit allows it to cover growing areas and produce plenty of harvestable shoots.
- Edible foliage: Young, tender leaves and shoots are eaten in several parts of the world.
Sea purslane isn't a magic plant that grows perfectly under every condition, but it offers another option for gardeners wanting to grow a wider variety of food.
For anyone interested in growing unusual edible plants, it's certainly worth experimenting with.
Growing sea purslane in aquaponics
This is where sea purslane gets particularly interesting.
Aquaponics combines fish or other aquatic animals with plants grown using nutrient-rich water. The aquatic animals produce waste, beneficial bacteria convert toxic ammonia into forms plants can use, and plants absorb nutrients as the water circulates through the system.
Sea purslane can be a good candidate for this style of growing.
Research has documented sea purslane production in aquaculture and brackish-water aquaponics systems. It has also been investigated for its ability to take up excess nutrients, including nitrogen and phosphorus, from water.
That doesn't mean every aquaponics setup will automatically produce outstanding results, but there is genuine scientific interest in this plant as both an edible crop and a useful component of aquatic growing systems.
Why it can work so well
1. It tolerates wet growing conditions.
Sea purslane naturally occurs in environments that can experience flooding and waterlogged conditions. This makes it an interesting candidate for water-based growing systems, provided the roots still receive adequate oxygen.
2. It can make use of nutrients in the water.
Like other plants, sea purslane needs nutrients to grow. In aquaponics, nutrients supplied by fish waste and bacterial processes can help support plant growth.
3. It offers a different type of edible crop.
Instead of relying entirely on lettuce, herbs and other familiar aquaponics plants, sea purslane gives you another edible green to experiment with.
4. It has potential in saline aquaponics.
Because sea purslane tolerates salt, it has been grown in brackish-water aquaponics research systems. This opens up interesting possibilities for systems designed around salt-tolerant aquatic species.
How to grow sea purslane in your aquaponics system
If you're adding sea purslane to a backyard aquaponics setup, I would start with a small trial rather than dedicating an entire grow bed to it.
Step 1: Start with healthy cuttings.
Sea purslane is commonly propagated using stem cuttings. Take healthy, disease-free stems and remove any leaves from the section that will sit in your growing medium.
Place the cuttings in a moist propagation medium or suitable aquaponics media, keeping them warm and allowing them to develop roots before moving them into their permanent position.
Step 2: Choose a suitable grow bed.
Sea purslane can be trialled in media beds or other suitable soilless growing arrangements. A media bed containing clay pebbles or another clean, inert growing medium is a practical place to start.
Make sure the bed drains properly and the roots receive sufficient oxygen. Even a plant that tolerates flooding can suffer when roots remain in poorly oxygenated conditions.
Step 3: Give it plenty of light.
Sea purslane generally grows well in sunny conditions. Strong light encourages compact growth and healthy foliage, although newly propagated cuttings should be allowed to establish before being exposed to the harshest conditions.
In the Top End, watch how the plant responds to intense afternoon sun and extreme heat. Some protection during the hottest part of the day may be useful while young plants establish.
Step 4: Monitor your water quality.
Keep an eye on pH, ammonia, nitrite and nitrate, just as you would with any aquaponics crop.
Don't assume that because sea purslane tolerates salt, adding salt to a freshwater aquaponics system will improve growth. Salt can accumulate and affect fish, plants and the overall system. Only introduce salinity when the entire system has been designed for it and the livestock can safely tolerate it.
Step 5: Let it establish before harvesting.
Once the cuttings have rooted and new growth is appearing, allow the plant to develop a healthy network of stems. You can then begin harvesting small amounts of the tender growing tips.
Regular, careful harvesting encourages branching and helps keep the plant productive.
Will sea purslane improve water quality?
Sea purslane has been studied for its capacity to absorb nutrients from water, including nitrogen and phosphorus. That gives it potential as a useful plant in integrated aquaculture systems.
However, it should not be treated as a replacement for proper mechanical filtration, biological filtration or adequate aeration.
In a backyard aquaponics system, think of sea purslane as another plant that may help use available nutrients, not as a substitute for a properly designed filtration system.
And remember that nutrient uptake varies with plant size, light, temperature, nutrient availability and harvesting frequency.
Growing tips for a healthy sea purslane crop
You don't need an elaborate setup to get started. Sea purslane is adaptable, and a few basic practices will help you get the most out of it.
Propagate from cuttings
If you can obtain a correctly identified, healthy sea purslane plant, cuttings are usually the easiest way to get started.
Choose firm, healthy stems and place them in a moist growing medium. Keep them warm and avoid letting the cuttings dry out before they have developed roots.
Once established, the plant can spread readily.
Choose a sunny location
Sea purslane generally prefers plenty of sunlight. In tropical areas, give established plants a sunny position, while watching for signs of excessive heat stress in small plants.
A plant growing in a hot, exposed position may need more consistent access to water than one growing in a protected location.
Don't overcomplicate the growing medium
In a conventional garden, sea purslane can grow in sandy, well-drained soils. In aquaponics, a suitable inert medium or purpose-designed soilless setup can work well.
Avoid using contaminated soil, unknown industrial waste or materials that could introduce harmful substances into your system.
Harvest regularly
Harvest the tender growing tips and young leaves rather than stripping the plant bare.
Leaving enough foliage behind allows the plant to continue photosynthesizing and producing new growth. Regular light harvesting can also help maintain a bushier shape.
Keep an eye on pests and plant health
Sea purslane is generally considered adaptable, but no edible plant is completely immune to problems.
Check for discoloured leaves, damaged stems, insects and signs of root deterioration. In aquaponics, investigate water quality and oxygenation if growth suddenly slows or roots begin to deteriorate.
Don't add salt just because it is a halophyte
This deserves repeating.
Sea purslane can tolerate salt, but it doesn't require salty water to grow. In fact, it can grow in non-saline conditions.
If you're growing it alongside freshwater fish, start with your existing freshwater system and observe how the plant performs. You can experiment with a separate saline or brackish setup later if you have a specific reason to do so.
How to harvest sea purslane
The most useful parts for the kitchen are generally the young, tender leaves and shoots.
Once the plant is well established, snip off fresh growing tips as needed. Wash the harvest thoroughly with clean drinking-quality water before preparing it.
Young shoots tend to be more tender than older, tougher stems, making them a good starting point for salads and quick-cooking dishes.
If your plant is growing in an aquaponics system, make sure the water and growing equipment are suitable for producing food. Never harvest edible plants from water contaminated with chemicals, unsafe waste or other pollutants.
Important: Correct identification matters. Don't eat a wild plant simply because it resembles sea purslane. Confirm that it is Sesuvium portulacastrum and that it has been grown in a safe environment.
Cooking with sea purslane
Sea purslane isn't just an interesting plant to grow. Its succulent leaves have a naturally salty flavour, which makes them useful in the kitchen.
Depending on the plant and growing conditions, the flavour can be mildly salty, fresh and slightly tangy.
In different parts of the world, sea purslane is eaten raw, cooked or pickled. If you're growing it at home, here are a few easy ways to try it.
1. Fresh sea purslane salad
This is a simple way to appreciate the plant's natural flavour.
Ingredients
- A handful of young sea purslane leaves and tender shoots
- Cherry tomatoes
- Cucumber
- A squeeze of lemon or lime
- A drizzle of olive oil
- Black pepper
Method
- Wash the sea purslane thoroughly and remove any tough stems.
- Combine the leaves and tender shoots with chopped tomato and cucumber.
- Dress with olive oil and a squeeze of lemon or lime.
- Add black pepper and taste before adding any extra salt.
The natural saltiness of sea purslane means you may need less added salt than you would in an ordinary leafy salad.
2. Garlic and lemon sautéed sea purslane
A quick sauté is an easy way to use a larger harvest.
Ingredients
- Two handfuls of young sea purslane
- One or two cloves of garlic, finely chopped
- A small amount of olive oil
- Lemon juice
- Black pepper
Method
- Wash the leaves and shoots thoroughly.
- Heat the olive oil in a frying pan over medium heat.
- Add the garlic and cook briefly until fragrant.
- Add the sea purslane and toss for a few minutes until the leaves soften.
- Finish with lemon juice and black pepper.
Serve it as a side dish with grilled fish, chicken or other barbecued food.
Keep the cooking time short so the leaves retain some of their texture.
3. Pickled sea purslane
If your plant is producing more than you can eat fresh, pickling is another option.
Sea purslane has been used in pickled preparations in several regions, and its naturally salty flavour can work well in a tangy accompaniment.
For a simple refrigerator pickle, use a tested recipe for vegetables and prepare the sea purslane with a vinegar-based brine. Keep it refrigerated and follow the recipe's storage guidance.
Don't assume that a homemade refrigerator pickle is shelf-stable. For jars intended to be stored at room temperature, use a properly tested preservation recipe with appropriate acidity and processing instructions.
4. Add it to eggs or stir-fries
Sea purslane can also be added to scrambled eggs, omelettes or quick stir-fries.
Try tossing a handful into a pan towards the end of cooking, allowing it to soften without becoming overly mushy.
It can be particularly useful when you want to add something fresh and green to a meal without relying on the usual supermarket vegetables.
A few things to keep in mind before eating it
Sea purslane is eaten as a vegetable in several parts of the world, but there are a few sensible precautions.
- Check the species: Make sure the plant is correctly identified.
- Use clean growing water: Aquaponics water quality matters, especially when growing food for direct consumption.
- Wash before eating: Clean the leaves and shoots thoroughly.
- Consider the salt content: Its natural sodium content can be relatively high, depending on growing conditions, so factor that in if you need to limit sodium.
- Start with a small serving: As with any unfamiliar edible plant, try a modest amount first and see how you tolerate it.
Sea purslane also contains calcium oxalate crystals, so it shouldn't be treated as a risk-free food simply because it is edible. If you have a relevant dietary restriction, seek appropriate advice before making it a regular part of your diet.
Is sea purslane worth growing in your backyard?
I reckon sea purslane is an interesting plant for anyone who enjoys experimenting with unusual edible crops.
It offers a combination of salt tolerance, succulent foliage, creeping growth and culinary uses that makes it stand out from more familiar backyard greens.
For tropical gardeners, it's another plant worth exploring. And for aquaponics enthusiasts, it presents an opportunity to trial a salt-tolerant edible crop that has already attracted scientific interest in aquaculture and nutrient-removal research.
The biggest advantage is that you don't need to build an entirely new system just to get started. If you can source a healthy plant, try propagating a few cuttings and growing them in a small section of your existing setup.
Observe how quickly they root, how much new growth they produce and how the leaves taste. Your own growing conditions will tell you a lot about whether sea purslane deserves a permanent place in your garden.
And that's what growing your own food is all about: experimenting, learning and finding more ways to produce something fresh at home.
Grow your own damn food.
Barry's Backyard note: Sea purslane (Sesuvium portulacastrum) has been investigated in scientific research for its salt tolerance, edible shoots and potential use in aquaculture systems. Its performance in any individual backyard aquaponics system will depend on the growing conditions and water quality.