Not in a container but here is my experience growing watercress in the garden, Star Stuff: The neighbor has a 4" irrigation pipe along the fence line. A few years ago, his main irrigation valve had a leak and the water traveled about 100 yard were it leaked out of the irrigation pipe along the fence line. It was actually leaking thru several years. I talked to him about how I was going to take advantage of that: put in a 2" pvc pipe and ran that slowly leaking water to a little pool in my garden about 6 feet away from the fence. The pool was about 2' by 4' and 6" deep. The soil here is very rocky so drainage isn't a problem. I just replaced some of the top soil in the bottom of the pool after I'd dug down about 10". A trip to the grocery store provided me with the watercress starts. I remember that the pool ran dry once or twice for half a day or so. That didn't seem to make any difference to the plants. They were lush and beautiful. The next year, the neighbor replaced his irrigation valve and my little pool was filled in and went back to being a bed in the garden. I think I embarrassed him . . . digitSteve

It just goes to show the filter is working. The roots should be consuming excess nutrients like crazy. Since the good bacteria grows everywhere there is good water flow supplying oxygen I doubt the watercress is hurting anything. If it worries you, rip some out. You may leave a lot of roots behind but they will either provide a source of nutrients for the good bacteria or will send up new plants. What you have right now is a combination Skippy/veggie filter. The questions I would ask are: has there been a heavy rain?(even not so heavy rain can mess up the PH), are my fish flashing?(Milt in the water can cause cloudy water),am I overfeeding?(this is the most common problem.), what does my test kit tell me( testing is important)? All of these things and more can be pertinent to cloudy water. If you don't have a test kit, get one and use it. It is a lot better than guessing and getting the wrong answers. You should use it at least once a week. Get a jarful of pond water and allow it to settle for several hours. If the problem is soil or other material has gotten into the pond, it will either settle out or float. That would mean you need to do a little more filtering and water changes to make it go away faster. Otherwise you can just wait it out.

Watercress will grow in almost anything as long as it has water. It will grow is saturated sand, saturated gravel, wet soil, or just in water. I think wet to very damp soil will be fine. If it gets too disgusting, just rinse all the soil away from the roots and plant it in saturated sand or gravel. Watercress likes some nutrients, so use a very diluted solution of miracle grow instead of water. I'm thinking a solution maybe one-fourth to one-eighth of the recommended level for fertilizing houseplants would be good.

Barbara, I have used hoop houses made of PVC pipe frames covered with 4 or 6 mm plastic to extend the harvest by growing earlier in the spring or later in the fall. You can use the same types of hoop houses to grow cold season crops all winter long if you want to. I suspect the hardest part for me would be to build one that could handle the hard north winds. If you are in town where there are other houses, other buildings like sheds, some fences and hedges, trees, etc. in close enough proximity to serve as a windblock, I think a hoophouse would be very easy to erect and maintain all winter. As Ilene mentioned, Eliot Coleman's "Four Season Harvest" is the classic book on the subject. One technique I learned from him was to use a frost blanket-type row cover on top of plants that then have further protection from a hoop house or high tunnel. That way, there are two layers of protection from the cold weather. However, Mr. Coleman, who is nothing less than a national hero to many farmers/market growers and serious hobby gardeners, has a brand new book out (April 2009) called "Winter Harvest" and even though it is primarily aimed at market growers, a serious home gardener could benefit greatly from reading it and applying his techiniques. People who've read both "Four Season Harvest" and "Winter Harvest" have stated in their reviews that basically "Winter Harvest" is an updated version of "Four Season Harvest" that includes what he's learned or changed or refined since he wrote "Four Season Harvest", so I don't know that you'd need to read both. Although, I do have to say that every word he's ever written in a book or magazine article or in any of the speeches he's given over the years is well worth reading! A couple of the most important things to remember about growing in a hoophouse or high tunnel or in short tunnels (more about them later) or cold frames is that you have to be able to open doors or vents to let heat out during the day or your plants will roast. Also, the larger the structure, the easier it is to maintain the appropriate temperature because very small structures heat up too fast and also cool down too quickly. You can use short tunnels that consist of wire or PVC hoops placed over garden rows and covered with floating row cover, plastic or both. They'll keep plants somewhat warmer, but not as well as a larger structure that has more mass. You can help increase their ability to hold heat by using a soil heating cable run down the row or plastic bottles spray-pained black and filled with water and used as solar collectors. I have used those big cat litter jugs spray-painted black as solar collectors in a hoophouse to protect early tomatoes from a late freeze with sleet and snow (and didn't lose a plant). If you use only a frost blanket type of floating row cover, I believe you pick up about 8 degrees of winter protection. With plastic, you can increase that and you can increase it a bit more with solar collectors. I haven't read "Winter Harvest" yet, but it is on my list of books to read before winter arrives. Finally, although some people have success using PVC framing, others may need to use electrical conduit as framing if they are in a high wind area or in an area where snow or sleet are likely. Another way to support a hoop house structure in those more difficult conditions is to use cattle panels as part of the support for the plastic roof. The Ardmore-based Noble Foundation has done a great deal of research into using hoophouses in agriculture. I've linked some of their data below that tells you how to errect a low tunnel. Also, you can cruise around their website or google to find their various instructions for making hoophouses (and raised beds) of different materials. Dawn Here is a link that might be useful: Nobel Foundation's Low Tunnel How-To