I am belatedly joining in this week's Saturday Spotlight series hosted by Liz on her blog Suburban Tomato. I had a BIG pile of garden soil delivered on Friday so a good chunk of Saturday was spent with my wheelbarrow and shovel, which then necessitated a long soak in a hot bubble bath, and then a therapeutic glass of wine, which meant that the planned Saturday Spotlight post got put off until Sunday, which may very well get published when it's closer to Monday in Liz's part of the world.
It seems appropriate to me that I'm writing about watercress to link to Liz's Saturday Spotlight series since it was her watercress harvests a few months back (maybe more than a few) that inspired me to try to grow it. So, first a confession, I really don't know what I'm talking about when it comes to watercress. I'm writing about it to share what I've learned and hopefully to get some help from successful home watercress growers. There's a bunch of bad information on the web about growing watercress. One site which purported to tell home gardeners how to grow watercress had one single photo of a tired bunch of supermarket purchased hydroponically grown watercress - uh huh. I should have just moved right along but I read on out of curiosity. I knew that the author had no clue when he/she advised to sow the little tiny truly minuscule seeds 1 inch deep. Even I knew better than to try that. That's when I went to my bookshelf and pulled down a couple of my favorite books for some expert advice.
In his book Heirloom Vegetable Gardening, William Woys Weaver gives a little history about watercress in the States which is interesting but I won't go into that here. He also gives advice about growing it in a stream, but I don't have a stream so I'll skip that too. Then he gets to the information that is useful to me - how to grow it in a pot. The Victorians seem to have figured out how to grow watercress in a pot. The book has a copy of an engraving from 1876 showing a 15-inch pot filled with pebbles, sand, and rich soil, and also sporting a healthy bushy growth of watercress. The pot is set in a saucer filled with 2 inches of water. He advises that the water be changed daily. The saucer of water not only keeps the soil wet, it also keeps the pot cool by means of evaporation. He also advises that the plants can be kept cool on hot days by adding some ice cubes to the saucer (probably not something that the Victorians resorted to!). The plants can be grown for a couple of years, brought indoors to a sunny window or kept in a coldframe during the coldest weather, then started over again with cuttings or seeds planted in fresh soil.
Pam Pierce has advice geared to my local growing conditions in her book Golden Gate Gardener. She advises using soil with lots of organic matter and placing the potted watercress in a container of water - that advice has not changed since Victorian times. It grows best in light shade and is happiest in the cool seasons and in the coolest microclimates. She also advises to apply a liquid fertilizer once a week, ah, something that I've not been doing so I suppose a splash of 4-1-1 fish emulsion won't hurt. More helpful advice from Pam includes thinning seedlings to 2 to 3 inches apart and pinching them back when they are 6 inches tall to encourage branching. Flowering stems need to be pinched back because they are more bitter, but it's OK to let them bloom if you want to collect seeds, the plants are perennial and will continue to grow after they've bloomed. Once you get a planting going it is easy to propagate more plants from either seeds or cuttings. Cuttings root readily and when potted up can produce a new crop in as little as 2 weeks. Aphids seem to be the main insect pest that afflict watercress and Pam says that they are an indication that you are doing something wrong - crowded plants, too much shade, not enough food, not enough water.
So, now that I've done my research after trying to get some plants started, oh so typical of me, let's see how I've done.
My favorite local seed purveyor, Renee's Garden Seeds, carries what they call English Watercress (from Dutch seeds - whatever), so back in February I picked up a packet of seeds at the hardware store and followed the directions (mostly) on the seed packet. I sowed some seeds on the surface of the soil in a 4-inch pot and kept the soil moist and indoors in a cool spot that got bright light but no direct sun. What do you know, the seeds germinated and I actually managed to get them to continue to grow. But then I let them continue to grow in their little pot until they became too crowded to separate and plant out individually. So I simply cut the whole mass into four parts and planted them all into a larger pot and set them outside in one of the few spots around here that doesn't get direct sun, isn't within munching range of the deer, and is easy to get to with a hose.
Here's an ugly picture of my potted watercress in the corner by the gate under the oak tree only 15 feet from the hose bib (I have an 80 foot hose which should be 100 feet but that's another story). This area gets dappled shade in the morning to about midday and then full shade during the hottest part of the day. So I'm doing a couple things correctly, the pot is in a shady spot and sitting in saucer of water, but perhaps it would enjoy a deeper saucer.
This is what it looked like yesterday after I snipped off a lot of the shoots. The biggest problem with this planting is that the plants are far too crowded. I have 4 clumps of seedlings about 2 inches apart. I should have thinned out the seedlings in each clump to let the remaining plants have more room to grow. It would be much better to have only 4 to 6 plants in a pot this size.
The result is spindly shoots that are trying to bloom. They are a bit extra spicy, but at least they aren't tough yet, and they taste OK in small doses.
The good news is that some of the stems are starting to send out some roots so I snipped a few of the biggest shoots and placed them in a jar of water.
Voila! Lots of roots. My next experiment will be to pot up the individual shoots into roomier pots and see if the less crowded plants will produce larger leaves and not want to bloom so quickly.
I'm thinking of trying to grow a pot in a small fountain basin that gets part to full shade most of the day and full sun part of the day. The fountain doesn't work well and I don't run it these days but the basin gets fed fresh water whenever the drip system runs so the plants will get plenty of fresh water there. I'm going to pot up a few other shoots and try them around different parts of the garden to see just how much sun or shade they will tolerate. I'm also thinking that an unglazed clay pot set in deeper water will keep the roots cooler and not encourage anaerobic conditions. Now that I know that the shoots root so easily I will have plenty of material to experiment with. Actually, you could skip the whole nurturing from seed thing if you can find a nice fresh healthy bunch of non-hydroponically grown watercress at the market and just root a few stems.
Do you grow watercress? Got any advice for us wannabe growers?