How to Grow Watercress the Easy Way

I have been growing watercress (Nasturtium officinale) for a little over ten years, I wrote a blog post on it in 2014.  It is a simple plant to grow, and people seem to rave about watercress, yet for some reason people are told it is difficult to grow.  I am happy to say this is not the case, and watercress can be grown and be productive in very little space. 

Some people assume there is some connection between watercress and nasturtium (Tropaeolum majus).  Even though the Genus of one and the common name of the other are the same, the two are not closely related in any way.  Garden nasturtium is native to Peru, while watercress is native to Eurasia.  Apparently the garden nasturtium got its common name because it produces an oil that is meant to be similar to watercress.  

Occasionally people contact me to ask about growing water cress, so I thought I would write another post explaining how I grow it.  This may not be the best way to grow it, but it is simple and very cheap.  It is really simple to grow watercress.  

Watercress is one of those vegetables which really needs to be eaten soon after harvest.  I never see it for sale in markets, but have been told some places sell it and it will last a day or two in the fridge.  For this reason, if you want to eat it you really should grow it yourself.  

I am told that watercress is a perennial vegetable.  It self seeds so readily for me that even after all these years of growing it I am not yet sure if it is perennial, or if it is an annual and there are always new self seeded plants.  It doesn't really matter if it is perennial or not, once you plant it you can always have some growing if you look after it.  

Watercress

When I tried to look up how other people grow watercress, I found many pictures of people who had sprouted the seeds in an egg shell with a pair of scissors in hand, or people who had ponds or elaborate hydroponic set ups.  This is of no use to someone who wants to grow enough in their backyard to eat (not just an egg shell's worth of sprouts) and/or who lacks a pond or aquaponics set up.  Luckily, watercress really is simple to grow.  

I have grown watercress in several climates, and have found watercress really simple and forgiving.  I tend not to eat it much because I am not overly fond of the taste, so I don't usually grow much of it.  The way I grow it, however, is cheap, and easy, and could easily be ramped up to produce a lot more of it if you were really fond of the taste.  

The first thing to know about watercress, is that it needs soil to survive, not just water.  Like basically any plant you can grow it hydroponically, or using aquaponics, but you can't grow it in a glass of water and expect good results.

The second thing you need to know is watercress needs sunlight (or a grow light).  It will not grow in water without sunlight.  

Watercress needs water, and can grow as an emergent plant with the roots submerged and the leaves in the air, but it copes surprisingly well in soil that is not particularly wet.  Sometimes the seeds fall and plants grow in the lawn among the grasses and weeds.  Not a problem, it doesn't tend to become a weed as it will die in the lawn over summer when it gets too dry for grass to perform well.  As an added bonus, if I ever had a large enough patch of this spring up by itself I can always pull it out and feed it to my chickens.  

Watercress - note the many roots on the stem

Watercress seems to grow better in cooler weather, but does not love frost and thick ice.  It seems to survive being frozen here, but also seems to get a little damaged by frosts.  If I move it under a tree where it in in a frost shadow the water freezes but there is no frost on the leaves and it seems to do fine.

It suffers a little in the heat of summer unless it is given some shade.  Giving some shade in summer also seems to make the leaves grow a little larger.  

The flowers of watercress are similar to any brassica in that they are adored by pollinator insects.  The flowers have a slight fragrance, and are edible.  They smell slightly sweet, and (probably due to all the nectar) taste a little sweet too.  Many people prefer eating the flowers to the leaves. 

Watercress is simple to grow from seed.  The seeds are tiny but simple to germinate, and it takes some time before the plants are large enough to harvest.  Sprinkle some seed on damp soil, keep it watered, make sure it has some sunlight, and it will grow well.  It takes a while for the seedlings to grow, and they are tiny for what feels like a long time, but you end up with a lot of plants. 

Watercress is easier and much faster to grow from cuttings.  Watercress stems grow roots readily when in or near water.  You can cut a stem into short lengths, and either plant them in damp soil, or put the ends in water (with the tops out of the water), and they grow easily.  

There is no trick to this, they don't need a humidity dome, they don't need rooting hormones, often they will all grow.  Sometimes the stems will already have roots before you cut them off.  Once they have some roots, you can just plant them in damp soil and they will grow well.

Watercress seedlings grew in this pot buy themselves

The main issue I have noticed with growing water cress (other than needing to provide water, soil, and light) is cabbage white butterflies.  These will lay eggs on watercress, and the caterpillars will eat out the plants.  I have also had watercress eaten out by water snails, and the plants are sometimes inundated by aphids, but issues with water snails or aphids seem to be intermittent and only strike once or twice per year.  

For me the cabbage white butterflies were the biggest issue.  I am told that cabbage white butterflies are not a big issue, but I found the opposite to be true in my garden for the first few years.  For a while my watercress was growing well only to be eaten to death in a day or two by these caterpillars.  

Then a tiny parasitoid wasp (Pteromalus puparum) appeared in my garden.  This tiny wasp lays eggs into the cabbage white pupa, and eats them out from the inside.  They reduced the numbers of cabbage white butterflies in this area.  While they will never eradicate the cabbage white butterflies, the have lowered the numbers enough for them not to kill off my watercress.  Now the cabbage white butterflies are not a big issue for me.    

You could grow watercress on the side of a pond.  You could grow watercress in hydroponics or aquaponics or even barrelponics.  I am happy to say that you don't need any of this to grow watercress well long term.  It grows well if it is in a pot of soil that is kept moist.  I find it is easier if I grow watercress in soil in something with no drainage.  The bottom of a plastic milk bottle works well.

Watercress, brahmi, and duckpotato

I cut the bottom off a plastic milk bottle, fill it 3/4 with soil, water well, and plant watercress into this.  

As long as the leaves are in the air it grows well, if totallt submerged it will rot and die.  You can plant cuttings which grow faster, or seeds which take longer to reach full size.  

If growing from seed, I make sure that the soil surface is not underwater.  Once the seedlings grow I can fill the milk bottle with water so long as they have some leaves that are not submerged.

The milk bottle in the pictures below was filled with soil and leaf litter that was dug out of the drain in front of our garage.  There is little point buying potting mix, drain soil (or leaf litter cleaned out from the house gutters) is free, and it is full of nutrients.  

Drain soil and leaf litter will have weed seeds, these will germinate, but they won't survive long.  Once the cutting is taller I will fill the container to the top with water, most weeds do not like being under water constantly.  The leaf littler and other stuff in there will break down over time and help feed the watercress over a long time. 

Milk bottle with soil

Watercress cutting with roots

Cutting planted into soil and given water

Once it grows larger I will add more water

It does not take long for the watercress to spread, and for the milk bottle to be brimming with watercress.  I often put azolla and duckweed on the water surface, these act as living mulch and help the tiny ecosystem to be healthier. 

Sometimes I grow watercress in the milk bottle by itself, other times I grow water cress mixed with other water loving things.  Below you can see some brahmi in with the water cress.  There is also a little duck potato in there.  As you can see, the tiny ecosystem is relatively healthy and this milk bottle is productive.

I often just put soil directly into the milk bottle, but you can also put soil in a small pot, and put the pot in the milk bottle.  It doesn't make a lot of difference to how the watercress performs.

Milk bottles don't last forever as they degrade and get brittle in sunlight.  Presumably they are food safe, and if not used for planting things into they would be thrown out.  I have some that have lasted 4 years ad look like they have a few more years left in them, others I have moved often and handled roughly, and they only lasted 2 years.  

These milk bottles were something I already had and were going to be thrown out anyway, so using them to grow watercress, Chinese water chestnuts, and other aquatic edible vegetables is a good thing.   

Growing watercress in a milk bottle

There are a few improved varieties of watercress, but I don't know if any are available in Australia.  All of the varieties I have grown seem much the same and I would not be able to tell them apart if not labelled.  

I once considered breeding an improved variety of watercress, but never got around to starting this breeding project.  This plant is so simple to grow that I don't know if improved varieties are even needed.  I am also not blown away by the taste, so there is little incentive for me to put the effort into improving this already useful and productive vegetable.  

I sell small plants or well rooted cuttings through my for sale page.  I plan to collect seed and also sell seed packets.  You only need one plant to get going, from there you can take cuttings or plant out some seed and expand your patch as much as you want.  

Vietnamese Fish Mint

I have been growing Vietnamese Fish Mint  (Houttuynia cordata) for years, yet for some reason I have never written a blog post on it before now.  

This plant has many common names, including dokudami, 'poison blocking plant',  lizard tail, heartleaf, fishwort, bishop's weed, and it has a heap of other common names too.  I usually just call it 'fish mint'.

Vietnamese Fishmint is a perennial vegetable that not at all related to mint.  It is edible and used as a vegetable or herb, it has a long history of medicinal use, as well as a long history as a remedy for poisoning.  

This is an essential vegetable in Vietnamese cooking, and appears to be eaten extensively in South East Asia.  This is very uncommon in Australia, yet extremely simple to grow and very productive.

Vietnamese fish mint in flower

Fish mint has a strong and rather distinctive smell.  Some people love the taste of fish mint, others not so much.  Some people liken its smell to oranges, others think it smells like fish, to others it smells like the gravel in the bottom of a fish tank.  

Vietnamese Fish Mint tends to be eaten raw, or only lightly cooked/wilted.  It does taste a lot like fish sauce, and can be used to make a vegetarian fish sauce.  When raw it tastes a bit too...I'm not sure how to explain it...perhaps too 'metallic' for my liking.  Once slightly cooked I prefer the taste.  Other people tell me they can't taste any of the metallic taste that I notice, so I guess it differs from person to person.  

Fish mint can be used to make a Vegan Fish Sauce.  Seriously!  How cool is that.  I found a recipe that I shared below, but if you have a better recipe and are willing to share it I would love to learn more.  

It is also used to make a medicinal "dokudami" herbal tea.  I have made this a few times, it tastes nice but I find the smell to be a little too strong for me.  My kids have tried the herbal tea, they like it.  I have made herbal tea using fish mint as well as other herbs such as lemon balm.  This was nicer, but I still found the fish mint to be overpowering.  

The rhizomes are used in a bunch of different herbal remedies, many of which have been proven to be effective.  Unfortunately I don't know how to make these medicines.  Presumably just eating the rhizome is enough to gain some benefit.  I find the rhizomes to be less overpowering than the leaves.  

Vietnamese Fish Mint 

Many animals, including chickens, quail, ducks, guinea pigs, sheep, and pigs gladly eat fish mint.  It has a lot of nutrients and some medicinal benefit.  Interestingly, fish mint has been demonstrated in many peer reviewed papers to protect chickens from bronchitis (https://pubmed.ncbi.nlm.nih.gov/21848486/), as well as treat coccidiosis in chickens and lambs as effectively as commercial coccidiosis medication.  I am tempted to grow this in a hanging pot in the chicken run so the hens can get the benefits of an organic coccidiosis treatment.  

There are several varieties of this plant.  I grow the most vigorous green version with single flowers.  There is a green one with double flowers, and there is also a multicoloured variegated one that looks really pretty and spreads less vigorously.  I am told the green one is not only more vigorous, but also more potent.  My chickens gladly eat the leaves, but I don't give them many, so I am glad I grow the most potent version.  

The leaves of the variety I grow are green, heart shaped, and they look very similar to buckwheat leaves.  The flowers are white and not overly interesting.  Bees and other insects visit the flowers, but never seem overly keen on them.  I am happy to say that the variety I grow never produces viable seed. 

Fish mint on left, buckwheat on right 

Fish mint grows extremely vigorously.  Let me stress, it is extremely vigorous.  One or two pots of this plant will be more than enough for the average household.  I am happy to say mine does not set any viable seed, ever, which makes it much easier to control.  Never grow this in the soil or it will take over your yard, and your neighbour's yards, and every time you walk in the yard or mow it will smell like fish.  Grow it in a pot, but never in the garden bed.  

I grow most of my fish mint in a container, and the container is on pavers.  My main one is in a plastic tub that we drilled holes in, it's not very deep but it is wide to allow the plant to spread, but any plant pot would do.  The rhizomes will try to escape through the drainage holes, but they can't cross the pavers.  

I have been growing this plant for seven or eight years and it has never escaped on me.  I also grow some in pots on wire shelves in my greenhouse, but these are being grown out to sell at markets and through the post.  

Fish mint escaping it's pot

Fish mint does not produce seed, or at least the one I grow has not produced any seed in the time I have grown it.  This is not a problem because it is easily divided to produce more plants.  If it did produce seed I am not sure that I would be willing to grow it because it spreads so vigorously.  

This plant is not related to mint (Mentha sp) and does not taste or smell even vaguely similar to mint.  I believe the word 'mint' in its common name is probably due to the way it spreads aggressively via underground rhizomes like mint.  

As well as being easy to divide, this plant grows readily from cuttings.  Planting cuttings in soil seems to result in 100% strike rate if the soil is kept damp.  I have only tried striking a cutting in water once, this grew well for me but not as fast as the ones planted in soil.  

I have never tried to restore fertility and grow from seed.  I prefer that it does not produce seed as it stops it from escaping into my yard.  I have considered getting the prettier variegated form, but don't know if a second clone would increase the possibility of viable seed, so for that reason have resisted the urge to get the variegated form.

When grown in a pot, some rhizomes will try to escape through the drainage holes.  Any rhizomes that try to escape the drainage holes can be roughly torn off, planted in a pot of damp soil, and will produce more plants.  They grow very quickly from rhizomes and produce large healthy plants very fast.  

Fishmint rhizomes potted up and ready to grow

Fish mint grows well in part shade, and survives in full sun.  It seems to prefer damp areas, but does not need to be waterlogged to grow well.  I have heard it can be grown as an emergent water plant, but haven't grown it like that myself.

Mine gets pretty dry at times over summer, if it looks like it is burning off I give it some water and it bounces back quickly.  I imagine if the soil got too dry for an extended period it would die.  This plant has a strong will to live, and tends to recover easily from all kinds of poor treatment.  

I have seen fish mint growing in floating pots on a pond.  I love the looks of this, and think it would do well in cleaning the pond water when grown like this.  Care would need to be taken that the pot did not get too near the edge and allow the plant to set root into the mud on the bank, as it would be difficult to remove once it became established.  

Fishmint goes mostly dormant over the winters here.  I say 'mostly dormant', because some years all the above ground parts die back, and other years it just looks scraggly and keeps a few leaves here and there.  The underground rhizomes survive very cold temperatures, easily coping with -10C with frozen solid soil, and it grows vigorously once the warmer weather returns.  

I am told that people (often in the US) grow the weaker variegated version of fish mint under trees or near ponds where it looks lovely.  They soon regret this as it takes over the yard, and it smells like fish every time they mow.  This is where my hesitation to grow it in a floating pot on a pond comes from.

Spraying does not kill this plant, herbicides easily kill the above ground parts, and it quickly resprouts from many underground rhizomes.  This is a plant that does not want to die.  I have heard that it can survive under weed mat for years, and pop up once their is a rip in the weed fabric.  

The simple way to deal with this is don't grow it in the garden bed.  Grow it in a pot, and have the pot on pavers.  As I mentioned, mine has never escaped and I have grown it for seven or eight years.  

Vegan Fish Sauce Recipe 

I found a recipe for vegan fish sauce here, it is so simple.

Ingredients: 1 cup packed fish mint leaves; 3 Thai chili peppers; 2 cloves garlic; 1/3 cup sesame oil; 2 tbsp rice wine vinegar 

Instructions: Puree all ingredients in a food processor. Transfer to a bowl and serve.

Other Fish Mint Recipes 

I also found a recipe for Fish mint that uses rhizomes as well as leaves.  It also is very simple.

Ingredients: 1/4 cup shredded young fish mint leaves, 1/4 cup chopped fishmint rhizomes, 4 tablespoons soy sauce, 2 tablespoons rice vinegar, 1 tablespoon fried chili crisp or chilli oil, 1 tablespoon chopped coriander cilantro, 1 tablespoon chopped scallions.

Instructions: Combine all the ingredients and toss shredded fishmint leaves and rhizomes. Chill for 10 minutes before serving.

As well as another recipe that includes tofu.

Ingredients: 200 g fish mint stems, broken into 4 cm lengths (or lotus stems), 8 fried tofu cubes, 1 handful of chopped mint leaves, 1/2 cup coriander, roughly sliced, 1/2 cup garlic chives, roughly sliced, 1/2 cup red peppers, finely sliced 

Dressing: 3 tbsp light soy, 2 tbsp black vinegar, 1 tbsp brown sugar, 2 spring onions, sliced, 1/2 tsp dried chilli flakes, 3 garlic cloves, diced, 4 cm piece of ginger, finely sliced.

Instructions: To make the dressing, in a bowl, combine the light soy sauce, black vinegar, brown sugar, spring onion, chilli flakes, garlic and ginger. Stir well and set aside for a few minutes to infuse.

In a large mixing bowl, combine the fish mint stems, tofu, mint, coriander, garlic chives and red peppers. Add the dressing and toss to combine. Transfer to a serving platter.

I have only shared a few recipes above.  There seem to be a host of similar recipes around, plus many families have their own family recipes.  If you have a good recipe and are willing to share it let me know and I can add it.  

Vietnamese fish mint

I mentioned earlier that this plant is vigorous, and I find the smell to be overpowering.  Some people adore fish mint, so much so that they will drive an hour each way to pick up a plant from me.  

I don't want to detract from the many benefits of this plant, so please read my opinion of its smell while keeping in mind that different people like different things, and that some people adore fish mint.  Fish mint is also incredibly healthy to eat, both people and animals benefit from eating it, so please don't take my comments to mean that you should not grow and eat this.  

I really can't cope with the smell of fish mint.  It is too strong for me.  Even repotting this can be too much for me at times.  

Other people comment how they adore fish mint, and most people I sell it to rave about it.  I had a few people drive out to buy fish mint plants from me cry tears of joy.  They told me they cried because it is a taste of home, a very dear memory, and they were fearing that they would never be able to eat this again after moving to Australia.  

While I don't think anyone should ever grow this in the garden do to how rampantly it spreads, I think this is well worth growing to see if you like it.  If you like the taste it is increadbly healthy to eat.  I also know that this plant makes a cherished gift to Vietnamese or Chinese friends.  

This plant is very useful for making Vietnamese spring rolls, Pho, and dokudami herbal tea.  People who buy this from me often say that they are thankful that they will never be without it again.

I have been selling organically grown Fish Mint plants for years through my for sale page along with other perennial vegetables I have for sale in Australia.  If you are interested go and have a look.  I either sell small fish mint plants, well rooted cuttings, or dormant rhizomes, depending on the time of year.  If selling rhizomes I tend to include extras, they will all grow once it starts to warm a little.  Over winter they are mostly dormant, and look very shabby, but they grow like mad once the weather warms.