How to Grow Watercress

Days to germination: 8 to 12 days
Days to harvest: 50 to 60 days
Light requirements: Full sun and partial shade
Water requirements: Constant moisture
Soil: High in organic content
Container: Almost required

Introduction

Though having some natural water in your yard can help, you don’t actually need a stream to grow watercress. But a large bucket, bin or even a kiddy pool could do the trick. While the plants do need a lot of water, they can still give you a harvest if grown in soil.

Since growing right in a stream is unlikely for most people, these instructions will be for anyone wanting to grow watercress in pots.

Watercress is a perennial that can survive the winters up to zone 5, though dealing with the water-filled containers can be awkward when the weather drops below freezing.

Delicate watercress leaves have a peppery flavor, and are usually eaten fresh and raw in salads or sandwiches. Cress has lots of vitamins A, K and C as well as calcium and iron. It’s a very healthy green. If you use it in cooked dishes, it will be much milder in flavor.

Starting from Seed

You can germinate your seeds indoors, but the fine roots make transplanting difficult. It’s easier to plant your seeds right into their final pots instead.

Before you do any planting, you need to prepare your “water garden” area. You’re going to need a large container for water, and smaller pots that fit inside it for the soil. A small pool is ideal, but a series of buckets can work just fine.

Choose pots that will fit inside the larger container, and fill them with potting soil mixed with some lime. Add extra stones to the bottom to make sure the soil won’t wash away through the drainage holes in the bottom. Now fill the larger container with water, and set the ones with soil inside.

The water level should not be higher than the tops of the inner pots. In fact, the water level can be quite low as long as the bases of the inside pots are always sitting in water. Even just a large tray would work but during the hot and dry months, it won’t likely hold enough water. You would end up having to refill the tray several times a day, which is not exactly ideal.

Set the whole thing up where your plants will get lots of sun, but partial shade during the hot afternoons.

Leave it long enough for the water to soak up through the drainage holes and saturate the soil. Once the soil is good and wet, plant your seeds to a depth of about an inch. The seeds should be spaced around 3 to 4 inches apart. A 12 inch pot can hold about 4 plants.

If you can’t find any watercress seeds, you may be able to start plants from fresh watercress that you get at the supermarket. Put a few sprigs of it in a glass of water, and leave it in a sunny spot. If you are lucky, the cut ends will sprout roots that you can transplant out into the same wet pots as described above.

Growing Instructions

As long as you never let your plants dry out, there should be little for you to do with your watercress plants until you want to start harvesting. Every 2 or 3 days, empty out the water from your “pond” and add fresh water. If you let the water sit for too long, it will stagnate and your plants will be stunted or even die. They need fresh water constantly.

After the growing season is over, watercress is surprisingly hardy during the winters. They can tolerate being frozen, though letting the water in your pool or bucket freeze can end up splitting the containers. Leave your entire growing set-up in place until you start to get hard freezes each night. Then drain out the larger pool, and leave the actual watercress pots somewhere sheltered.

Until the pots actually freeze for the winter, add extra water each day so they don’t dry out. Once frozen, they should be fine until spring. Once they start to thaw, add more water again until the frosts have passed and you can replace their “pool”.

Containers

As mentioned above, since most people do not have streams handy, this article reflects the techniques for growing watercress in containers.

Even if you do have natural water nearby, container growing is cleaner and you don’t have to worry about water-borne diseases contaminating your plants.

Pests and Diseases

Watercress is typically only bothered by 2 main insect pests: flea beetles and mustard beetles. Both of these small beetles can do a lot of damage to your plants by chewing on the leaves.

The easiest way to get rid of them is to dunk your entire pot of watercress underwater for about an hour. It won’t harm the plant (though some soil may wash away if you’re not careful), and the insects will either drown or be washed off the plants.

Some gardeners will plant a few extra radishes nearby to attract these same insects away from your watercress plants.

Harvest and Storage

You can pick the leaves of watercress for use, but make sure you don’t disturb the roots. Use a pair of scissor to cut the leaves and tender stems off, rather than pulling. Wait until the stems are about 6 inches long, then you can snip them off close to the soil level. Never take more than a third of any plant at one time.

Once your plants go to flower, the leaves will quickly lose their lovely flavor and get bitter. So your harvest period usually runs from spring into late summer, depending on your climate.

Watercress does not store for very long once picked. Wrap the pieces in a plastic bag, and keep in the fridge. It will start to wilt after just 2 or 3 days so make sure you do your harvesting right before you intend to you it. Unfortunately, due to the high water content in watercress, it will not freeze well enough for any long-term storage that way.

12 Responses to “How to Grow Watercress”

george gusler Says:
May 31st, 2011 at 6:37 am
I have a small stream from an artesian well. I would like to start watercress in this trenched runoff. I need information of where to get these seeds. Thank you
deardora Says:
July 8th, 2011 at 3:57 pm
Found seeds at nearest garden center, brand was Botanical Interests.
MKP Says:
December 6th, 2011 at 6:22 pm
I bought my seeds on line from Park Seed Co.
Rouge Says:
September 17th, 2012 at 7:05 am
Why not buy watercress from your local farm shop. Make sure you taste it first it should have that lovely peppery flavour. If the watercress has roots you can plant it in a container with good potting compost, water it daily and feed it weekly. If the watercress you buy does not have roots place the stems in water and in 2 or 3 days roots will start to apear.

Good luck enjoy Rouge
patricia jarrett Says:
September 21st, 2012 at 9:27 pm
thank you so much it was a great help
Sarah Says:
January 5th, 2013 at 12:14 pm
What about the sanding water attracting mosquitos in the summer? That is my only fear.
Sarah Says:
January 5th, 2013 at 12:15 pm
I mean “standing” water.
Lilli Says:
January 9th, 2013 at 8:43 pm
Sarah you could float some vegetable oil on the surface however I think because the water is being refreshed every few days that the mosquito lavae would not have enough time to grow into an adult. Also you could add some minnows or mosquito fish to the water if deep enough but remember not to throw them out when refreshing.
Funny about Money Says:
February 14th, 2013 at 11:46 am
Sounds like “how to grow mosquitos.” Wouldn’t floating vegetable oil on the surface harm the plants?

What if you had a series of buckets or similarly shaped containers, either one a little taller than the next or arranged on supports so one or two are higher than the others. Then you could use a small aquarium pump (sold as small fountain pumps at home improvement warehouse stores) to move and recirculate the water. Add a couple of goldfish to each container to take care of the skeeters.

The circulation would help keep the water fresh longer, and from what I recall about the cress that grew on our ranch, the plants favor gently flowing water. Occasionally you would probably have to transfer the fishes and clean it out, unless the idea is to create a wild-looking pond.
milly evans Says:
March 23rd, 2013 at 6:39 am
I bought my watercress seeds from Bunnings, it’s that simple. The packet contained 1000 seeds so i had heaps. Check it out if you are looking for these seeds.
Kelley Says:
March 25th, 2013 at 10:23 am
I have grown watercress some. I have found that the need to constantly give the plants fresh water leaches out nutrients. Do you recommend fertilizer? If so, what kind? I have also wondered if I need to add lime to keep the pH high. (I don’t have a pH meter.)
Jeff Joseph Says:
April 20th, 2013 at 1:03 am
Hello,
We have a water feature stream in our yard.
Can we plant Watercress in the pond part or should we plant in the stream part?
Are we better to have lots of clay in the pot or more like potting mix?