Your Opinions On The Walstad Method?

If you look at my posts here, you'll see I have also used this method for all my tanks and I'm very happy with it. It's simple (and cheap!) and makes perfect sense. I also have a biological background and work as an ecologist, so I guess it has a natural appeal to us.

I missed the boat somewhat when starting up my new tank last year - with just getting back into fishkeeping I stuck with what I knew for ease and didn't consider the Walstad method. Whilst everything is fine, with hindsight I wish I had gone down the 'dirting' route as my current setup is restricting my plant density and I may have to look at ferts + CO2. I did set up a dirt test in my small QT tank at the weekend but it subsequently sprung a leak (probably due to moving it around whilst containing water) - good job there were no fish in it!

It's well-established that plant growth is always limited by a single factor, the scarcest resource. This is known as Liebig's law of the minimum (look it up on Wikipedia or somewhere). This might be e.g. a particular nutrient, light or carbon dioxide. So if your plants are not growing well because of lack of one nutrient e.g. phosphate, then adding carbon dioxide or increasing light will not benefit them. As I mentioned in a previous post, my plants have always shown a spurt of growth very quickly after adding fish. I'm sure that in a fishless tank carbon dioxide was limiting. However, I've become convinced that in a normally stocked tank your fish will produce plenty enough. In "high tech" and aquascaped tanks, both nutrient and light levels are kept artificially very high and no longer limiting factors so that adding carbon dioxide is beneficial as that is now the limiting factor, particularly as many of these tanks are very lightly stocked with fish, the plants being the main interest  . However, this doesn't mean that the same is true for "normal" tanks. I'd try root tabs first, as they are the easiest option. Don't forget that micronutrients, particularly iron, can often be limiting factors in aquaria, so it might also be useful to try a few drops of one of the liquid fertilisers that provide these. Unless your tank is very lightly stocked, I'd consider carbon dioxide last.

Incidentally, the limiting factor for algae is almost always found to be a nutrient, although aquarists tend to blame excessive light. So anyone who has an algal problem should look at the nutrient status of their tank before worrying about light.

Floating plants grew like crazy in my tanks at first, but slowed down later, by which time the nitrate level had declined considerably, presumably they had used it up. Floating plants obviously take up all of their nutrients from the water, while rooted plants often have a strong preference for obtaining some nutrients, especially phosphorus, via their roots from the substrate. In any case, as using root tabs is so simple compared to increasing CO₂ I'd definitely try it first. Diagnosing plant nutrient problems is always tricky, even an excess of one nutrient may give the same symptoms as deficiency of another. And there's also the issue of hardness, Ca and Mg are both essential for plant growth ....................

Thanks Steve

I have never read anything about the Walstad method, but I am sure it closely resembles what methods I use for my aquariums. That is my knowledge of organic gardening. Basically just replicating nature. I use a good quality substrate, plants that are suitable for my lighting(low light), bogwood, driftwood, rocks,etc. And a properly stocked tank. Nature will take its course.    I did see some post saying they did few water changes though, and that seems terribly wrong. Nature replaces water all the time in tropical areas. Its called RAIN.

The Walstad method is, at heart, very simple. Most of her book gives the technical background, but you don't have to understand it. For me, it's all summed up by her as "Essential to my natural aquarium is moderate lighting, a substrate enriched with ordinary soil, and well-adapted plants." That's the nub of it. The biggest difference from most is the use of ordinary soil as a layer under the gravel, rather than one of those ridiculously over-priced "special" substrates.
As far as water changes are concerned, I see no reason to change water so long as the parameters are OK. I wouldn't go as far as Walstad ("I change about 25 to 50% of the water every 3-6 months.") but neither do I see the need for a ritualistic weekly water change without good reason. The Walstad method is really the idea of the balanced aquarium revised and updated.  Large water changes are a good way to "unbalance" a balanced tank. The main reason for water changes appears to be to reduce nitrates, but strongly growing plants will themselves use up a large part of the nitrate load.In many tropical areas, rain falls for only a short part of the year. I've lived in a part of Africa where the dry season is 9 months long. The rivers rapidly dry up into a series of pools which then shrink in the heat (40^oC every day). Fish are trapped in these pools in conditions which would seem intolerable, but they survive and many breed at this time. When the rains come, they are suddenly exposed to a torrent of water 15^o cooler, but they live through all this with no problem. In the Amazon region, and I'm sure in many other areas, fish collectors can only catch many fish when they are trapped in pools in the dry season, as they are much too dispersed when the rivers are full. Apparently millions of Cardinal tetras can be found in some of these pools, where they will stay for months. Obviously they don't get any water changes during this period.

Sounds good, but i found it to be too messy.

Well, i used Miracle Grow planting mix instead of soil, it contains a lot of organic material, as well as fertilizer, and capped it with about 2 inches of natural colored gravel.

This produced, a great media for plant growth, but also encouraged algae, and as the organic decayed lots of tea colored water, which i dont mind, but it was also next to impossible to vac without stirring up a lot of debris.

i think this method would be best suited to a tank that is to be left alone to do its own thing.

I unintentionally came across this which some might find intersting: A Basic Approach to the Natural Planted Aquarium.