Watercress (Nasturtium officinale)

20180304_101138_001Not only is this a ridiculously easy plant to grow, but it’s tasty, nutritious, and can be used as a functional part of a water feature in your landscape.  Score one for versatility!

Watercress naturally grows in streams.  I grow mine in a waterfall that flows into a small fish pond I have.  This picture shows my watercress getting too crowded and slowing water flow.  Time to harvest!

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Watercress is a leafy, low growing plant whose leaves and stems are edible.  The taste is a wee bit peppery, kind of like arugula, but not as sharp.  It is a perfect addition to salads and I love adding it to my tuna salad sandwiches.

*A handy growing summary chart is at the end of the article.*

Watercress roots can form dense mats, which is great for helping filter my pond water.  However, I have to find all the little rocks that got trapped so I can put them back in the waterfall!

Watercress can be found growing alongside, or even floating in freshwater streams, usually in dense patches.  Should you decide to harvest your own, be certain you know what you are actually collecting!!  There are many plants that look similar, and not all will leave you amongst the living if you eat it.  There is also a real risk of picking up liver flukes, a parasite found in livestock, so you are taking your chances if you harvest from a stream that may flow through areas visited by livestock.  I will also say that I am not a huge fan of collecting things from the wild because other living things want to use them, too.  Please do not rip out entire clusters of plants or trample over areas.  Watercress stems can be snipped just above the base, leaving the roots behind, and will then quickly rejuvenate with new growth.  You can grab a few stems, and follow my instructions below for growing much, much more at home (and no wet shoes!).

I rip out entire mats of watercress from my waterfall.  No need to worry about being gentle!  I will rinse out the roots and water other plants with the nutrient rich rinse water.

Watercress can also be grown from seeds.  Seeds can be started anytime indoors, or grown in early spring when daytime temperatures are 50-60 F.  Start with a tray filled to a depth of one inch with very damp potting soil designed for starting seeds.  The tray should NOT have drainage holes, since watercress is naturally adapted to a very wet environment.  The seeds are very small, so just sprinkle them lightly over the surface of the soil.  Using a spray bottle or hose with a nozzle set to mist, moisten the soil until it is saturated.  If you live in a cooler climate (zone 7 or lower), you can keep your seed tray in the sun, however you will want to provide some shade in warmer climates.  As the seedlings emerge, they can have more sunlight, but it is important that the soil never dry out.

The small clump of watercress I leave behind will grow back soon, but for now the water flows freely.  I found the rocks!

Though you can buy seeds for growing watercress, it is easiest to start from cuttings.  If your local grocery store carries fresh watercress, you are in luck!  Fill shallow pots or trays (with no holes) with very damp potting soil.  Stick the stems of watercress from the store into the soil and moisten it until it is saturated.  Place the pots in either full sun, or dappled shade in warmer zones, and make sure the soil never dries out.  Ta-da!  You’re done.  It’s really that easy.

Our hot sun stunts the growth of watercress, but a week in the shade will fix that!

Better, yet, if you have a water feature in your yard, watercress can become a part of it.  I have a small pond with a couple of fish, that has a little waterfall attached.  I use watercress as a biological filter to help keep my pond clean, and then I get food!  Yay, me!  I tucked stems of watercress from the grocery store in between the rocks that are in my little waterfall.  The watercress soon grew a dense mat of roots that helps trap organic material, clarifying the pond water.  The watercress also uses that material as nutrients for it to grow.

See, nice and tall now!

Harvesting watercress is also very easy.  When the plants have grown a few inches tall, just snip the stems near the base, leaving a couple of leaves and the roots behind.  If your plants stay too low to cut, put them in full shade.  This will cause the stems to elongate and give you a better stem to cut.  I will tear out entire mats of plants from my waterfall when they get too crowded, leaving a small patch behind.  I then place them into a plastic tub filled with an inch or two of water, then place them in the shade.  The hot sun here in zone 9 keeps them too low to be harvested well, unless they are in the shade.  In about a week, my plants will have stretched out and it’s chow time!

Just a snip snip here, and a snip snip there.

Plant Summary:

  • Perrenial
  • Evergreen
  • Height: up to 5-6 inches
  • Width: will keep spreading if you let it
  • Sun: full sun in cooler climates, part sun in zone 8+
  • Water: needs constantly moist soil
  • Soil pH: 6.5 – 7.5
  • Soil type: grows best in very loose soil, or even in rocks with flowing water
  • Key nutrients: balanced
  • Planting time: best to start in cool spring after freeze danger has passed




9 thoughts on “Watercress (Nasturtium officinale)

  1. Just remember. If you are growing it in an area that could be contaminated by animals like sheep, cows, goats, deer and rabbits that it is advisable to cook watercress to prevent infection from the liver fluke parasite.

    Liked by 1 person

    1. Absolutely an excellent point! Another reason not to harvest wild plants. I had heard about this concern in the past, but forgot. Thanks for bringing it up!


  2. As much as I like watercress, this is one of those vegetables that I have never grown, and would probably like more if I did not know where it came from. I remember seeing a similar specie growing in some weird places. It seems to me that there is a native specie as well, although it may be of a different genera. I do not remember.

    Liked by 1 person

    1. I only became aware of watercress a few years ago. When my husband was a kid he would nibble on some that he found growing near a creek up in the foothills. I’m sure he knew nothing of parasites at that point! I started mine from grocery store stock, and I know exactly where mine is growing so it’s all good!

      Liked by 1 person

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