Green Man Publishing

Garden building materials

Once you have an area planned out, you can start thinking about what materials and surfaces to use. For the most part these should be fairly simple and inexpensive (ostentatiousness doesn’t go well in the garden). The zoning concept is helpful here, in that it places the hardest wearing, most manufactured and attractive materials near to the house (where they get the most wear and are most visible). These are also the most expensive materials (both financially and ecologically) and are only needed in fairly small quantities in this limited area. Softer, more natural (and cheaper) materials are used further away from the house. This gives a nice gradation which helps the house blend into the garden.

The hardscaping (built) elements are the most energy and resource intensive and expensive part of a landscaping job. It’s up to you to decide how much hardscaping you have and of what kinds, but many gardens have far more than they really need. Generally softer materials such as mulch, earth, plants or stone (all from the garden) work well enough for most places. Less is greener.

Financial impact

Even though most landscaping materials come out of the ground, they aren’t cheap because they are heavy and cost a lot to transport. If you just go down to a landscape supply store and buy all of your materials you can spend a lot of money. There are ways to avoid doing this but you do have to work at it. If you have a large garden you will soon realize one of its main disadvantages, you need a lot more of every material.

Environmental impact

When deciding upon the materials to use, you should consider the environmental impact of obtaining them. There are plenty of ways to spend money to help destroy the planet we depend upon (donate to your local congressman, buy an SUV or stock in BP), but gardening should not be one of them. There is no virtue in being tasteful and artistic in your own space if you are leaving a legacy of ugliness and destruction elsewhere (like those beautiful New Age shops selling crystals mined who knows where).

I would avoid all lumber cut from old growth trees (though most of these are just about gone anyway) as well as tropical hardwoods. I also try and avoid new brick and concrete because they require a lot of energy to make. Rock is often obtained in less than sensitive ways and leaves the landscape looking a lot less attractive than it was. A lot of stone is now shipped from China, which doesn’t seem like the most efficient use of fuel.

Sadly we can’t always afford the luxury of being totally pure, we have to do what we can afford. A lot of “green building” materials are so expensive their relevance is debatable. Hopefully they will get more affordable as they become more popular. Also the fact that you can afford to use “renewable” oak posts for your timber framed gazebo isn’t altogether being honest with yourself (we won’t save the earth by cutting down trees). Being green means making do with what you already have, scavenging, recycling and using your imagination rather than your credit card. Of course sometimes you have to buy stuff that will help you save in other ways (water pipe for a drip irrigation system will ultimately save you a lot of time and water).

A lot of the landscapes you see in books and magazines just flaunt their profligacy and almost seem designed to use a maximum quantity of natural resources. It seems the rarer and more costly the materials, the more exclusive (and hence better) it is thought to be. The average family doesn’t need 3000 square feet of Redwood deck or granite patio. I have a particular aversion to conspicuous consumption. It offends my sense of justice that some people have a complete second kitchen outdoors, with marble counter tops, stainless steel fridge, sink and grill, while others don’t have enough to eat.

A nice (though often overlooked) fact is that conserving resources can often mean conserving money. Using salvaged material is cheaper than buying new stuff and of course the resources from your own land don’t cost anything (if you count your labor in such an equation you need to spend more time in your garden).

Simple materials

Use the simplest and most inexpensive material that accomplishes the task you have set for it. For the most part this means using materials that can be found on the site, or are available locally. Most simple materials are also repairable, which means if they break they don’t have to be thrown away.

The best garden materials are not only simple, they are also weatherproof and age gracefully so they actually look better as they get older. Japanese gardeners particularly prize materials that are humble in origin but bear this patina of age and wear. They even have an expression for it: wabi sabi. This is one of the reasons Japanese gardens have so much character.

If you want the garden to be your personal refuge from the world, you might also want to avoid the materials and plants commonly seen in everyday life. These include asphalt, poured concrete, gravel, diamond trellis, shaped concrete pavers, bark chips, Junipers, Japanese maples, Petunias, Impatiens and the like.

Local materials

Your choice of garden materials should largely be decided by what is available locally. Look at what materials are commonly used in gardens in your area. Go around local garden centers and builders supply stores and check out what is available and how much it costs. This will also give you a better idea of the economics of your plans.

Using local materials not only saves on transportation, but it also connects the garden to the region around it. Every part of the country has some naturally available resources and you should use them for most of your needs. Around here we have a lot of Redwood in the form of boards, logs and poles, as well as various types of cordwood, shoots, brush, wood chips and sawdust. Other areas may have lots of stone, hardwoods, dry leaves, leaf mold, gravel, seaweed and more. Urban areas have unlimited possibilities for salvaging.

Extreme local materials

The first place you should look for materials is in your own garden. These might include poles, rocks (in rocky soils you will always be looking for ways to get rid of those you remove from the ground), logs, brushwood, sand and even earth (soil can be used for soilcrete or rammed earth, clay can be used for adobe brick, tiles, sealing ponds) and more. You should also think about growing materials (Willow, Chestnut, Bamboo) for use in the garden. See below For more on this.

Old and salvaged materials

If you can’t get something from your own garden, you will have to look further afield. The United States has an almost unlimited supply of used building materials of all kinds: lumber, windows, stone, brick, broken concrete and much more. This is where urban gardeners have a decided advantage over their rural sisters. You can find salvaged material for almost any use, the only requirement is a little imagination on how to use it (and a truck to transport it). Using salvaged materials is a cottage garden tradition and is almost essential if you are to build a garden without spending a lot of money.

Used materials also meet our criteria of being inexpensive and having little environmental impact. They also tend to have more character than bland new stuff. They come with a history and are pre-aged with a patina that helps to make the garden more unique.

The problem with the really nice old materials is finding them. If you just want to go and buy them you will pay “collectible” prices, because they will be sold as chic or antique. To get them at a reasonable cost you have to hunt for them. I find country and suburban yard sales to be one of the most fruitful sources of garden related stuff (also flea markets and thrift stores). Scrap metal yards can be a gold mine for metal objects. Dumpsters are good for construction materials. The town landfill is the ultimate place for salvaging if it’s allowed. Unfortunately Santa Cruz is very possessive of its garbage, preferring to bury a lot of it rather than allow people to recycle it (the town isn’t very friendly to dogs either). I have to mention craigslist.com separately as a fantastic resource for finding anything used. If it still has any value, it will be listed for sale there multiple times.

The key to getting salvaged materials is to pick up anything that might potentially have a use, when you see it. Don’t wait until you need something before starting to look. Many times I have passed something up and then I had a great idea of how I could have used it. This means you need somewhere to store all of this stuff of course.

Reusable materials

Some materials are relatively expensive to buy initially, but have a long useful lifespan and can easily be reused (Redwood, bricks, stone, metal). Just make sure you use them in a way that makes it easy to reuse them at a later date (set bricks on sand, not in concrete). Even better is to get them after their first use, when they are a lot cheaper.

Low-maintenance

The best materials are those that don’t require any maintenance after installation, Whenever you start having to regularly, clean, paint or bring things inside for the winter, you are looking at more work.

Buying materials

If you can’t use what you already have and can’t beg, steal or borrow it, then you will have to buy it. Try and get stuff when it is on sale, which means taking advantage of deals when they come along (often at the end of summer when shops are already thinking about Halloween). If you wait until the job grinds to a halt from lack of materials you will pay top dollar.

I always look out for stuff I can get at a reduced price. Broken flagstone, slightly twisted fenceposts, warped boards, bags of fertilizer with holes in them. The bigger stores will often give you a discount if you order a lot at one time

Growing your own materials

Gardening is an activity where we think in the long-term, so it’s not unreasonable to take this a step further and grow your own garden materials. Obviously these won’t be available when you first start your garden, but as time passes you will be glad you did (and most can be harvested over and over again). If such a plant is low-maintenance, ornamental and useful too, it can be a very worthwhile crop.

Suitable sized poles from any trees or shrubs can be used for plant stakes and supports. The long flexible stems of woody vines can be used for making baskets and as a base for wreaths.

Bamboo is a versatile garden building material and depending upon its size it can be used for fence panels, poles, plant supports and more. It is easily grown in most areas (the problem is keeping it under control).

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Willow is less well known than Bamboo, but has quite a few potential uses in the garden and deserves to be more widely utilized. Their long flexible shoots can be used to make arches and arbors to support climbing plants and as fences and screens. Thinner shoots can be woven to create wattle fence panels and as edging for beds. Willow is very easily propagated from cuttings and is so fast growing it can be used as a source of biomass for composting. It rots quickly if it stays wet, so keep it from contact with the ground .

Chestnut is a fast growing tree that can be coppiced to produce firewood, fenceposts, stout poles for arbors and palings for fencing.

Black Locust: This fast growing nitrogen fixer can be coppiced to produce rot resistant fenceposts and good firewood.

Some plants can be useful as twine for tying up plants. New Zealand Flax (Phormium) is the probably best for this, but there are many others. The stems of Honeysuckle and Morning Glory can be used directly. The leaves of Iris, Cattail, Stinging Nettle, Hemp, Flax, Kniphofia and Yucca can all be twisted and used.

Common local materials

Wood

Wood is one of the most basic and versatile garden materials and is used for fences, arbors, plant supports, furniture, ornamentation and much more. In some areas wood is abundant and fairly cheap, in others it is scarce and expensive. It’s best to use local wood where possible, especially that which has grown in your garden.

Dimension lumber

When I use sawn wood outdoors it is usually recycled, as it is cheaper, has less environmental cost and frequently comes with an aged look that I like. It helps that I have been a building contractor for a long time and often get free old wood (it’s the only fringe benefit of such a job). I also happen to live where Redwood is commonly used. This is so durable it is often re-usable, even after many years outside.

When I use new wood, I try to stick to the rule that whatever I build should last longer than the wood took to grow. This usually means using rot resistant wood outdoors, as anything else just doesn’t last. I also try to avoid direct contact between wood and the ground, as this drastically shortens the life of any wood.

I like to avoid pressure treated wood for the most part, though with the removal of the arsenic and chromium it has become significantly less toxic in recent years. If you do use pressure treated wood you should be aware that the preservative only penetrates about a half inch into the wood. If you cut the wood you will expose the untreated wood inside. Never put the sawn end of a pressure treated fence post into the ground, as it will rot within a few years.

When most softwoods go outside they are painted or stained to make them last longer. Unfortunately painted wood can’t be recycled easily. It may also be hard to re-paint if covered in plants. Stain often works better and it just fades away (I’m not sure about burning it though).

The recycled plastic “wood” such as Trex is rapidly gaining in popularity for use in decks and landscaping, as it doesn’t rot.

Wooden Poles

If you have coniferous trees on your property you may be able to obtain useful round poles from small overcrowded trees. You might also get hardwood poles by coppicing (these are usually more durable than softwood poles).

Poles can be used for all manner of garden structures: arbors, pergolas and the like. They will last longer if peeled and kept from contact with the ground (put them on concrete piers).

When I’m cutting trees I save any long poles with a fork at the end, as they make good supports for heavily laden fruit tree branches. Thicker poles can be used as fenceposts (see Boundaries for more on this).

Brushwood

This has a surprising number of uses in the garden and shouldn’t simply be burned as waste material. It can be used for plant supports (see Temporary plant supports), woven into fences or dead hedges (see Boundaries), or simple piled up as a windbreak or refuge for small animals.

Brushwood can also be used to enrich the soil. You can combine it with soil to make a berm, bury it in trenches on the contour, or use in hugelkultur beds. You can also leave it piles to slowly break down. If nothing else it can be used for mulch. I have a small electric shredder that works well for chipping small shrubs up to an inch in diameter. It gives me an easy way to produce small quantities of mulch and get rid of woody brush at the same time (it’s time consuming though).

Wood Chips

These are the all purpose material for paths and as mulch for permanent plantings. You can use as many wood chips as you can get, so be on the lookout. Around here tree trimmers are happy to dump a truckload on your property.

Stumps

If you can’t face the task of digging stumps out of the ground, they can be carved into pedestals or seats (this is only worthwhile if they are a durable type of wood). If they are already out of the ground they can be used for fences.

Shoots and suckers

Longer shoots, such as fruit tree prunings can be woven like those of willow.

Bark

This can be used as a long lasting mulch. Shredded bark is even better than chipped bark.

Stone

Stone is attractive, durable and comes in a wide variety of colors and textures. Local stone always looks great and helps to gives the garden a regional character. If you have stone in your garden it will be one of your most basic resources. If you don’t, but have a truck, you can often pick it up elsewhere (I mean this literally). Stone is almost prohibitively expensive to buy where I live.

Many areas are blessed (or cursed depending on your viewpoint) with an abundance of stones of all sizes. I used to moan about the rocky New England soil where every time you poke a fork into the ground you hit a rock. Now that I garden in almost completely rock free soil (and have stood in the landscapers yard goggling at the price of stone), I have developed a new appreciation of stone as a free resource. If you have enough stone it can be used for everything from edging beds and paving to building walls.

Stone looks and feels hard (because it is) and it should be used sparingly. It is most useful in small amounts, such as for stepping stones, paving, low walls. Too much stone may make your garden feel too hard.

Types or rock

Rock comes in every size from sand to gravel to pebbles to cobbles to boulders. All of these have their uses in the landscape, particularly as paving for paths and patios (See Paths for more on these).

Sand, decomposed granite

These are most often used as a base for paths and patios, but they can also be used as a surface material. Decomposed granite packs down firmly to form a fairly hard surface, especially if a little Portland cement is added.

Gravel

This inexpensive and versatile material makes a quick and easy path, though it may need edging to stop it spreading. It is also good for flat driveways.

Cobbles

These small 3-4” diameter rocks are commonly set in concrete for use as paving.

Block pavers

These rectangular stone blocks are one of my favorite paving materials, but are usually prohibitively expensive.

Boulders

These are commonly used for ornamentation, especially around ponds. They can also be used for low retaining walls.

Fieldstone

This is sedimentary rock that can be split along one plane to make randomly shaped flat sheets. These are used for paving patios and paths and must be fitted together like a jigsaw puzzle.

Flagstone

This is fieldstone that has been cut into regular squares or rectangles. It is the ultimate paving material, but prohibitively expensive where I live.

Adobe and cob – I haven’t had any experience with these, but apparently they have been used for garden walls.

Brick

Brick is not stone but is used like it for walls, paths, patios, pedestals, columns, path edging and more. Traditionally bricks were made of fired clay, but today they may also be made of concrete. Either way they are very energy intensive to produce, so I try to find used brick.

Salvaged brick is widely available but (because of the labor of cleaning it) may well cost more than new brick. If you live in the right area, you can probably salvage your own brick. Unfortunately in earthquake prone California we don’t have a lot of brick buildings left to demolish.

The big advantage of buying brick is that it is delivered to your site on nice neat pallets. Salvaging brick means going out and getting it yourself. Because of its weight (a single brick may weigh 5 ½ pounds) this becomes an act of ecological virtue (or poverty)). My little Toyota pickup struggles to carry much more than 200 bricks, which cover about 40 square feet of path. This means quite a few trips to get any quantity, so the closer the source the better. When you factor in your time, gas, considerable wear and tear on your hands, back and vehicle, and the time it takes to clean the bricks of mortar, those free bricks aren’t necessarily that cheap (or even ecologically virtuous).

Brick should be set in a bed of sand for good drainage. This also makes them easy to move and re-use. You can make a firmer bed from concrete, but this makes them harder to reuse in the future.

Concrete

This is so versatile that it gets a reluctant nod of approval even though it is energy intensive to produce and not always good Feng Shui. It is relatively cheap and can be used to replace some things that were once done by skilled hands (and are now prohibitively expensive), such as masonry columns for pergolas and retaining walls. Poured concrete is a very useful and versatile material. It can be colored, stamped, imprinted, carved, cut, embedded and more. Any time you do anything unusual you should experiment with a small area first, as it may not turn out as you expect.

Large areas of poured concrete should be avoided where possible. They are not good because they smother the earth, prevent rain percolation and are generally bad for chi. If you must use it (maybe for rainwater collection), then make expansion joints to stop it cracking. These can be simple saw cuts or they might be a row of bricks or other decorative features.

If you must use concrete for paving it is better to use it in smaller modules such as block pavers. These have become popular in recent years. Depending upon the type, they can look just like stone, or they can look very factory made and institutional.

It is possible to cast a few special personalized concrete pavers yourself to add interest to a path. This gives you a good opportunity to get creative with color  and by embedding various items. Making them is a lot of work though and I wouldn’t want to cover much area with them.

Salvaged broken concrete can be pretty versatile and has the added virtue of being a waste material. Again the big drawback is its weight. It is extremely heavy to transport and you won’t get many slabs in the back of a Prius. However if you are breaking up an old concrete driveway or patio then you should reuse it rather than dumping it.

Hypertufa is a concrete material made with peat moss to make it lighter and more porous. It can be used to create ‘stone’ containers for planting and as a coating for stucco walls. Concrete has also been made using soil instead of sand.

Metal

Feng Shui advises that you should have some metal in the garden. This might be fences, gates, furniture, sculpture or trellis. Metal goes particularly well with plants and can provide a variety of ornamental effects.

Copper pipe and plumbing fittings were once commonly used for trellises and arches, but they have become a lot more expensive recently. Steel reinforcing rods are cheaper and can be used to make large, strong and airy structures such as arbors (how about a large domed sitting area covered in vines?). You could wire them together (this makes them easy to re-use), though welding is stronger and more permanent.

Galvanized or copper pipe can also be used to make fountains.

Corrugated sheet metal is a too often overlooked garden material. A very versatile material, it can be used for much more than simply roofing. Use it for fences, walls, edging and retaining walls (paint the back of it with tar to prolong its life). You can often get this inexpensively at scrap yards and it comes with a nice patina of age (also known as rust).

Glass

This isn’t much used in gardens but it can be very ornamental in the form of sculpture, mirrors and old bottles. Old glass doors can make transparent panels for fences.

Plastic

Plastic would be entirely on my list of materials to avoid, except that it has several unique uses, that we can’t easily do without. It is the most practical material for lightweight greenhouse glazing, re-usable pond liners, garden plumbing and drip irrigation.

Materials to avoid if possible

The green consumer is a contradiction in terms. I don’t garden to give me a reason to buy more stuff and I try not to buy anything new (I know, this doesn’t help the GDP). However some products are particularly bad and I try to avoid using them when possible. Of course sometimes we end up using these things because they are all we can afford.

Hardwoods

Many landscaping books casually recommend hardwoods for outdoor use, with the qualifier that they are obtained from sustainable sources. This sounds “green” but what does that really mean? Cutting down a 100 year old Oak tree and planting an acorn could be called sustainable forestry (in fact it often is), but is your need for an arbor a good enough reason for it? Especially if you already have softwood poles growing on your land.

Tropical hardwoods

Some companies promote their “sustainably harvested Teak’, but of course these plantations are growing where natural forests once stood. The wood is then transported 1000’s of miles to your garden.

Old growth trees

Redwood and Cedar may not travel as far as Teak, but if you have ever seen the freshly cut stump of an ancient tree it might dampen your pride in that clear heart Redwood deck. On the other hand recycled Redwood is a fantastic material. Second growth Redwood can also be good.

Pressure treated wood

I appreciate the fact that pressure treated wood lasts much longer than untreated wood, but it is too toxic to use safely in many situations. Manufacturers claim the toxins are bonded to the wood and don’t leach out, but that is nonsense. The wood does eventually rot and the toxins go into the soil. Some people warn against using pressure treated wood near food crops, I prefer not to use it near anything.

Pressure treated wood has become considerably less toxic in recent years with the removal of the chromium

and arsenic. Be aware of this if you salvage old pressure treated wood, as it may well still contain these metals.

Concrete

I already discussed the virtues and uses of concrete. The big problem with concrete is that it usually means strip mining to obtain the limestone and a lot of energy and CO2 emissions to make the cement that holds it together. According to one industry website, producing a yard of concrete creates 400 pounds of CO2, which is the equivalent of burning 16 gallons of gasoline. I try to avoid concrete if there is any alternative.

Peat Moss

In England there has been a long campaign to get gardeners to stop using peat moss in the garden, because it’s use has resulted in the destruction of many peat bogs. I have already talked about considering the environmental impact of our materials and I commend these efforts. However you have to look at the bigger picture of where it comes from. In Ireland 10% of electricity is produced from peat burning  power stations. It’s use for starting seeds pales in comparison to this. I would never use it in quantity as a soil amendment though (leaf mold is much better anyway).

Paint

I don’t really recommend paint, It isn’t particularly durable outside (which means work repainting) and eventually breaks down into the soil. The soil around old buildings is often contaminated with lead from old paint (fortunately this is now banned). If you must use paint then try and use the newer eco paints. Another problem is that painted wood can’t be recycled.

VOC’s.

When possible you should avoid wood stains, glues and anything else containing volatile organic compounds.

Plastic

Plastic is toxic to produce, commonly breaks down in sunlight, is often hard to recycle and sometimes has hidden health effects. Unless specially treated for outdoor use (with toxic additives) it weakens and breaks down when exposed to the ultraviolet rays in sunlight (plastic tarps barely last through one season). There are some unique garden uses for plastics, but they are used a lot more than they need to be, simply because they are cheap and easy to manufacture. Plastic furniture, plastic cushions, plastic sheds, plastic fences, plastic tools, plastic trellis. All are ugly and not very strong (and when they break they are almost impossible to repair).

How toxic is that plastic?

When using plastic we should consider hidden costs, such as the pollution produced in its manufacture and disposal. The most commonly used plastics (from least toxic to most toxic) include:

High density polyethylene HDPE – The least toxic plastic for tanks and irrigation pipe. Polyethylenes are fairly simple polymers though they often contain additives for UV and heat stabilization. They are fairly easy to recycle and are a good substitute for  PVC.

Polyethylene-Terephthalate (PET) is made from ethylene glycol and dimethyl terephthalate. It often incorporates UV stabilizers and flame retardants. It is also fairly easy to recycle.

Ethylene propylene diene monomer EPDM – The least toxic plastic for pond liners and living roofs.

Cross linked polyethylene pipe (XLPE or PEX) is a good alternative to PVC if you can afford it. Like PVC it can’t be exposed to sunlight.

Polycarbonate – Used for greenhouse glazing and very durable. Manufacturing may involve using phosgene (of poison gas infamy), as well as methylene chloride, chloroform, 1,2-dichloroethylene, tetrachloroethane and chlorobenzene. It is possible to recycle polycarbonate, but it commonly isn’t.

Acrylonitrile-butadiene-styrene (ABS) Manufacture involves butadiene, styrene, acrylonitrile all probable human carcinogens.

Polystyrene (PS) manufacture involves (benzene) (styrene and 1,3-butadiene). It can be recycled, but commonly isn’t.

Poly vinyl chloride PVC – Used for pond liners and irrigation pipe. During manufacture dioxin and other dangerous pollutants are created. It commonly contains additives that aren’t chemically bound to the plastic and so leach out. It can’t be recycled because of its chlorine and additive content. I used it for my irrigation system without thinking about all of this, but now wish I hadn’t.

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