What is aquaponics?

Some natural gardeners focus on creating habitat for wildlife in their yards. Others focus on using their land to produce food for themselves. Within this second strain of natural gardening, growing fruits and vegetables is relatively easy (though some homeowners do find themselves in the bizarre situation of being threatened with jail time for having a vegetable garden in their yard). Raising meat at home is much more challenging: most towns don’t allow residents to keep cattle, pigs, or goats in their yards, and chicken-keeping is often limited to a small number of hens.

One solution to this problem is fish.

Yes, fish. It’s usually legal to keep them in your yard, even if you plan to eat them. As added bonuses, fish are easy to care for, and they don’t get diseases that can be transmitted to humans.

Once people realized that they could raise fish in their yards, they quickly came up with an even better idea called aquaponics. Aquaponics is the practice of raising fish and plants together. The fish live in an above-ground tank, and the plants grow in racks suspended along the water’s surface. Adding fish food once or twice a day jump-starts an efficient and productive system: the fish turn the fish food into fish growth and fish waste, and the plants turn the fish waste into plant growth and clean water.

Within a few months, the plants and fish become people food. Buying young plants and fish and raising them in this way is cheaper than buying similar food at the grocery store, so the practice is cost-efficient – plus, you know exactly where the food came from.

The system is mostly vertical, so it uses space efficiently. And it can be energy-efficient too. First, choose fish and plants that don’t mind cold temperatures. Green, leafy plants like lettuce, spinach, and herbs (sage, parsley, and basil, for example) work well. Then, build the system in a greenhouse in a sunny spot in your yard. This way, it will mostly heat itself.

Keeping the system running is not difficult. The plants will need adequate light and humidity. The pH value of the water must be safe for both the plants and the fish. And the water will need to be warm enough. If the air temperature around the system is cooler, that’s usually no problem.

Novice aquaponics practitioners might be inclined to begin with a small system, but larger ones are actually easier to manage. A tank that holds less than 100 gallons will experience faster swings in temperature, pH, and bacteria populations than a tank with more water, and will require more active management.

Overfishing and industrial fish farming are both serious environmental problems. We can enjoy fish more sustainably by raising it ourselves.

What is aquaponics?

Is global warming good for plants?

Some people deny that global warming is happening. Others agree that it is happening, but claim it isn’t a bad thing. People in this second group often say that global warming isn’t bad because all that extra carbon in the air will promote plant growth, which will benefit agriculture and the environment. Is this true?

Not really.

As described in the last post, plants do need carbon to grow, and they like having more of it around. But, they like extra carbon a little too much.

Let’s explore why by looking at humans and sugar.

Humans like sugar. We generally think of sugar as a bad and unnecessary thing that makes us fat. But, in fact, humans need sugar. In the past, sugar was rare and hard to find. Because sugar was important for human nutrition but difficult to get, evolution fitted us with a sugar craving that drives us to search energetically for this nutrient, and consume it whenever possible. This worked great until the modern age, when sugar became abundant and readily available in our dietary environment. Our biology hasn’t yet learned that it should tell us to eat a certain amount of sugar and then stop. And so, unless we manage to exert a lot of willpower, we end up eating too much sugar, and we get sick from it.

A similar mechanism is at work in plants. A plant’s biology tells the plant to absorb as much carbon as possible. This is very good for the plant as long as the amount of carbon the plant can realistically absorb is not greater than the amount of carbon the plant really needs. However, if a plant was able to absorb more carbon than it needed – for example, due to rising carbon levels in the atmosphere related to global warming – then the plant would happily gorge itself on the extra carbon. In a classic case of too much of a good thing, the plant would then become sick.

This is not just theoretical. Studies have found that plants that binge on carbon really do become unhealthy. Just like humans who eat too much sugar produce body fat that isn’t good for them, plants that absorb too much carbon produce abnormally high levels of starch. And while these plants are getting vegetatively flabby, they store less protein in their pollen.

This means that the plants are not healthy, their pollen does not contain the nutrients that pollen-eating animals need to be healthy, and the parts of the plants that humans eat are similarly lacking in nutrients that humans need to be healthy. Far from being a boon to agriculture, global warming puts plants on a junk food diet that is bad for everyone.

And that part isn’t theoretical either. Studies on how plants react to excess carbon haven’t just been done in the lab. In the US, plants living in the wild have shown a marked decrease in the protein content of their pollen since America began industrializing in the 1840s. That decline has been most severe over the past six decades, when America’s carbon emissions were increasing dramatically.

Global warming is a serious problem that we are running out of time to solve. At this point, we cannot decrease our emissions steeply enough to avoid disastrous warming on our planet. To prevent the worst impacts of climate change, we need to not only reduce our emissions, but also actively work to take carbon out of the atmosphere.

Humans have not yet invented technology that can take carbon out of the atmosphere. Fortunately, nature has. We call that technology plants.

Global warming will not benefit either humans or plants. But if humans and plants work together, we still may be able to solve this urgent problem.

Is global warming good for plants?

What if you don’t have a yard?

Believe it or not, you can have a natural yard without a yard.

First, if you have a balcony, you can put some native flowers on it. Bees and butterflies will find them!

Second, you may be able to join a community gardening program in your city. Working a plot provides all the benefits of the physical act of gardening (it burns almost as many calories as going to the gym!), plus you get fresh, organic vegetables at virtually no cost.

Third, you may be able to use what is called a landshare. Landsharing is a system in which a person who wants to garden but has no land connects with someone who has land but can’t or doesn’t want to maintain it. Someone in your community may be willing to let you tear up a section of their lawn and plant vegetables or native flowers, in exchange for a share of the produce and a reduced need to do yard work.

Small spaces can make a big difference. Together, we can create a healthier environment for ourselves and other species.

What if you don’t have a yard?

What is an herb spiral?

Ask a permaculture practitioner to name a design pattern, and they’ll probably describe the herb spiral – a way of creating a lot of microclimates and producing a lot of food in a small space.

An herb spiral is built by piling up a mound of soil. Stones are then placed in a spiral pattern down the sides of the mound, and the soil between the rows of stones is flattened out. This forms a sort of spiral path, which serves as a planting bed.

As the name of the design suggests, it is customary to plant herbs along the spiral. The plants are placed according to their preferred microclimates. A species that likes cool, damp spots can go at the bottom of the shady side of the mound, while a species that thrives in hot, sunny, dry conditions can go on top.

herb spiral

By building up, the spiral creates a lot of planting space in a small footprint. It also makes plants easier to reach.

Building an herb spiral outside your kitchen door can provide you with fresh flavor all summer long.

What is an herb spiral?

What is a keyhole garden?

Every vegetable garden needs paths – if you can’t reach the plants, you can’t eat them.

The simplest layout for a garden is to plant in rows, alternating planting beds with paths. This design, however, results in a lot of space devoted to walking, relative to the space used for producing food. That’s not a very efficient way to garden in a small yard.

Raised beds are a little more efficient. Because they’re higher and easier to reach, the beds can be wider, increasing the ratio of planting area to walking space.

An even better way is a layout called a keyhole garden. This design features a circular planting bed with an open work space in the middle, and a single narrow path connecting the inside to the outside. By standing in the center and by walking around the outer edge, the gardener can reach all the plants to care for and harvest them, while not taking up any more space than necessary for paths.

This image compares traditional rows, raised beds, and keyhole gardens.

Keyhole gardens must be relatively small, since they only work if the gardener can reach the middle of the planting bed from either side. When more space is available, however, multiple keyhole gardens can be linked together in a pattern called a mandala garden.

By using space creatively, we can produce a surprising amount of food, even in a small suburban yard.

What is a keyhole garden?

What is a lasagna garden?

No, it isn’t a garden that produces the ingredients for a baked pasta dish. Rather, it’s a type of raised bed that is built in layers, like a lasagna.

The first step in building a lasagna garden is to choose a good location and put down a layer of sheet mulch.

Next, add layers of organic material, such as compost, grass clippings, fallen leaves, or old newspaper. A frame can help to hold the materials together, but isn’t strictly necessary.

A lasagna garden should stand eight to twelve inches above ground level. It needs to be built higher than this, though, because the materials will settle a lot as they break down into soil.

As with a Hugelkultur bed, a new lasagna garden should be watered thoroughly, to help the materials break down and to provide plenty of moisture for the soil. Once the lasagna garden is established, it will hold moisture well and need little additional watering.

Late summer or early fall is a great time to build a lasagna garden. Plenty of yard waste is available for building up the layers. The material will break down over the winter, and will be watered in the spring by rain and snowmelt. Then, it will be ready for planting!

Seeds and seedlings can be planted directly into the lasagna garden. A final layer of mulch – such as straw or wood chips – will help prevent unwanted plants from inviting themselves in.

What is a lasagna garden?

What is a raised bed?

A raised bed is exactly what it sounds like – a place for plants that is higher than the surrounding ground. There are a number of advantages to raised beds.

First, when plants are grown on a higher level, it is easier for the gardener to reach them. Raised beds reduce the need for bending, squatting, or kneeling.

Second, raised beds are established by building up instead of digging down. This is generally an easier way of replacing a section of lawn.

Third, by working up from ground level, raised beds build soil. Healthy soil helps plants grow quickly.

Fourth, ground-level beds are tempting to walk on, but raised beds aren’t. Resisting the urge to walk on a planting bed helps avoid soil compaction, which is bad for soil quality.

The easiest way to establish a raised bed is to place a frame in the desired location, and fill it with store-bought soil. Frames can be bought at a gardening store, or built at home from scrap wood. Be sure to use wood that is not treated with chemicals, as the chemicals can leach into the soil and harm plants.

The next post will look at a special type of raised bed that supercharges soil and reduces work throughout the gardening season.

What is a raised bed?