Proper Paver Patio Construction

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Concrete pavers have come a long way in the last decade. Back then, they were essentially a compromise product: if the client wanted a patio and didn’t want a concrete slab, but couldn’t afford stone, pavers were almost as good. Now, however, the manufacturers have really stepped up their game. Aesthetics and quality have actually pushed pavers into the role of design choice, as opposed to budget alternative. For me, the top paver brands available in Northern Virginia are Techo-Bloc, EP Henry, CST, and Belgard. I’ve also heard some good things about Rinox, although I have yet to use them myself.

One of the biggest selling points for pavers has always been ease of installation. Once your base and bedding layers are set, pavers do go down very easily. However, base prep is critical to the success of your project. Any mistakes with your base will be visible in the finished patio in the form of high spots, low spots, or an entire patio that looks like an ocean wave. The very first paver walk I installed over a decade ago had that problem, because I rushed my base prep. I have to say, I didn’t enjoy laying those pavers twice.

The standard for paver installation is set by the Interlocking Concrete Paver Institute. If you’re planning on building the patio yourself, they have excellent step by step instructions here. Most paver manufacturers also provide product and technical guides to assist you with installation; ask your supplier for one. In my experience, these are some of the most important considerations:

  • Maintain a grade away from your house. Pavers with polymeric sand joints act just like a solid concrete patio. If they slope towards the house, all that water will go right towards the foundation.
  • You really can’t go too thick on your base material. Use common sense- obviously, base material’s not free- but four inches is the minimum.
  • Spend the money to rent a plate compactor. I used to work with an absolute moose of  a man, who was convinced he could get adequate compaction from a hand tamper. We put it to the test; he was wrong.
  • Read the manufacturer’s instructions on everything you use. Efflorescence is a normal occurrence with a concrete product, and they make cleaners especially for pavers. Mix the cleaner as directed, or you may damage your pavers.
  • Take your time. A project like this will always take longer than you plan. Don’t decide to lay a patio the day before your Fourth of July barbecue.

Proper design can make a huge difference in your finished product. Cuts are one of the more difficult tasks to do properly, so I’ve designed patios with almost no cuts. My personal best is a 400 square foot patio with only 43 cuts.  Obviously, if you want to save some money and get the satisfaction of doing your patio yourself, I can design it for you to help you get the most function from your space. I can also help walk you through layout and construction if you feel you’ll need just that little bit of a push. Or, if you decide that it’s above your skill level, I can certainly recommend a good contractor. No matter how you decide to proceed, a new paver patio can be a great addition to your outdoor living space this spring.

Retaining Walls Revisited

MJ (my wife) reads this blog, and she made a good point about my last post (“Retaining Walls- Always Needed?”). Her point was that this blog is for a general audience, and since I excerpted a conversation with another designer, the language was a little contractor-y. Re-reading the post, I’m inclined to agree, so I wanted to clarify some of my points in laypersons’ terms.

The first is the issue of “cutting and rolling” a grade. Essentially, if I have 12″ of grade change or less, I can often grade that into a gentle slope. This slope will grow grass just fine, and it’s gentle enough that it can be mowed pretty easily. This sketch illustrates that (the dashed line indicates the original shape of the soil):12in-for-web

The next scenario I discussed is a 12-24 inch grade change. A wall could certainly help things out here, but you can also grade it down without a wall. You’re left with more of an embankment than a slope, however, and how you plant it changes. It’ll be tough to get grass seed to take before it washes away. Sod will work, but you’re left with two concerns: because of the steep slope, the grass is in a perpetual “drought” condition, and cutting the grass with a mower will be pretty difficult. You’re more likely to need to trim it with a string trimmer. In a situation like this, I’d rather see the slope planted with a groundcover- be it a shrub or perennial- that will stabilize the slope. See the sketch below (again, dashed line indicates original grade):24-in-for-web

From 24 inches on up, retaining walls are a good solution for enhancing function and ease of maintenance. It’s always important to consider the visual impact of a wall. Unless there’s something you’re actively trying to screen, I’m a firm believer that the smallest wall possible is the best. A seat wall is typically in the 18-22 inch range. This is a comfortable sitting height for most adults, and it doesn’t block the views out of the space. The wall defines the boundaries of the space, but even from a seated position, you can see to other parts of the yard. It’s also a great way to get multiple functions from one investment: not only does it hold back the grade, but it provides overflow seating for parties. I’ve got one job in progress right now where the homeowners are maximizing space by using a seat wall as built-in seating for an outdoor dining table. To give you a sense of scale, here’s a sketch of a seat wall:seatwallweb

The only downside to a seat wall is that without a backrest, it doesn’t provide comfortable seating for extended periods of time. If you were to build an additional wall behind the seat wall, to act as a backrest, you’d ideally have something in the 30-36 inch tall range. Whether it serves as a backrest or it’s an independent wall, a 36 inch wall is beginning to visually impact your space. That’s the height of your kitchen counters. From a standing position, you still have unobstructed views to other portions of the yard, but from a seated position, there’s more of a sense of enclosure:36wallforweb1

In extreme situations, a wall even taller than this is required to get the function we need from the space. The biggest detriment to such a tall wall is the impact it has on the space:60wall4web

The aesthetics aren’t the only concern, of course. If you’re building a retaining wall in Virginia, you (or your contractor) are required to get a permit for any wall that will retain over 24 inches of material (local codes may vary, ALWAYS check with your local building office before beginning a project). Most municipalities offer a standard retaining wall detail, which makes it a simple process: if you build a wall from the materials they specify, in the manner they outline in the wall details, they have done all the engineering work for you. Typically, these packets cover construction of timber, block, and solid concrete retaining walls. Fairfax County’s wall detail is a good place to get an understanding of what goes into a properly constructed wall. If you’re looking to build a segmental retaining wall (products such as Belgard, EP Henry, Techo-Bloc, etc.) retaining more than 24 inches of material, that will also require a permit. In many cases, the supplier can provide you with the documentation required to get a permit.

While these standard details are excellent, they only cover walls up to 60 inches (5 feet) tall. Anything above that must be designed and stamped by a professional engineer. Not only is it the only legal route, having such a large wall engineered is critical for the safety of anyone who will set foot on the property. When a big wall fails, it can be pretty spectacular:wall-fail011

The bottom line is that there are always multiple solutions to any situation. Instead of one large wall, perhaps we can use several smaller walls and adjust the grading a little bit. Maybe a small wall can be used to reduce the slope a bit, and we can plant a groundcover for erosion control as well as beauty and habitat- turn a negative into a positive with a lush butterfly garden, for example. If there’s no getting around the fact that you need a big wall to make it work, starting the process with a good landscape designer can reduce your overall expenditures by minimizing the amount of walls needed and designing them in such a way that they unify the space. It also reduces your engineering fees if the wall is already conceptually designed. I can make it pretty; the engineer makes it work.

Retaining Walls- Always Needed?

I’ve been conversing with a new landscape designer in Ohio, and sharing with him some of my thoughts and work processes. He asked me how to determine when a retaining wall is necessary and when it’s not, and I kind of ran with it. I ask myself that same question every time I design a project with grade changes on the site, and it’s a decision that’s impacted by not just structural requirements, but also my client’s budget and my own, personal design philosophy. Here’s what I wrote:

Easy question first: retaining walls. Now, here’s a caveat- while my design aesthetic is either very formal, classical garden-style or very loose, natural, blurring-the-edge-of-the-woods (it all depends on the site and architectural context), my heart is with the mid-century modernists. Form follows function, and the goal is restraint. Why make the client pay to build more than they need?
 
As that relates to retaining walls yes vs. no- in my opinion, a retaining wall is a last resort. If the only way to make the space function as required is to build a wall, build a wall. Otherwise, figure out a different solution. Obviously you need to consider your local factors- soil type, how much load is uphill, how much water is coming from uphill (and at what kind of velocity), and where the water is going from where you are. But typically, if I have a grade change of 12 inches or less- I prefer to cut and roll it. If you do that, you can even plant grass on the slope and still maintain it, if you grade properly. 24 inches or less? If I can, I’d rather roll it. Something to keep in mind is that the top of your wall doesn’t HAVE to be even with the top of your wall. If you need to retain just a little bit of soil, you can use a curbing product like granite cobbles or whatever Techo-Bloc’s curbstone is. You can also do a short (8-12 inch) drystack fieldstone wall, and allow the slope to pitch into the wall or curb. A wall can also be used for aesthetics (to visually expand a space, or define a courtyard) or multiple function (like a seat wall). So I’m not saying walls are bad. Just make sure you have a reason for wall, not just “there’s a grade change, so I must need a wall.” I’ve had jobs where I could’ve gotten away without a wall, but a little one did make it look a little tidier, and probably prevented mulch landslides until the groundcover got established. So… use them, but have a reason.
 
You’ll get a feel for where you need a wall and where you don’t the more projects you get under your belt. I really have to bite my tongue looking at some of these online landscape forums, because these guys are clearly all about strutting around and seeing who has the bigger wall. Think of it this way: 18-22 inches to top of wall, you have a seat wall. Those are functional and don’t really detract from the space. 24-36 inches, you’re still not impacting your aesthetics too terribly much. 36-60 inches, you’re going to start feeling boxed in. Anything over five feet and a) you need an engineer, and b) you just made your space feel smaller. And, you’ve dramatically upped the cost.
 
Example: I just presented a design for a client. They have a modest house on a pretty standard-sized lot. Off the back of the house, you go about fifteen feet and the ground shoots up at at least a 40% grade. However, it’s a 20 year old home, and the slope is heavily wooded. With all the brush, it’s a stable slope. They’re also not having water penetration issues in the rear of the home,  so, my design didn’t include a wall. I kept the design very simple and functional. They have a lot of shade and they’re not super into gardening, so I did what made sense for them. They could renovate the entire landscape- including a new front walk and a small BBQ grill patio in the back, both made from natural stone- for around $20K. Or, for that $20K, we could do a 42″ wall made of 6×6 p/t timbers that wouldn’t buy them any more usable space. Needless to say, the client’s thrilled.
Just a little food for thought. Have a great weekend!
 

Some Must-Have Tools

Spring is right around the corner, which means it’ll be time for spring cleanups. Over the last year, I’ve invested in a few tools that make the process a lot easier. There are areas where one can save money, but I’m a firm believer that professional tools are important for professional results.

First is my favorite edging shovel ever, the King of Spades. Your reaction may be similar to MJ’s: “Eighty bucks for a shovel? Are you nuts?!” We used them at most of the landscape companies I’ve worked for, and once you’ve used them it’s hard to go back. The handle is lightweight aluminum, but the blade itself is steel. It comes from the factory with a pretty decent edge, but you can really put a great, sharp edge on the blade whenever necessary. In fact, that was part of the days’ procedure during mulching season: while I was loading the trucks with mulch, the junior guys sat at the bench grinders and sharpened all the shovels. The King of Spades cuts a beautifully deep and sharp bed edge; it’s also an excellent tool for digging transplants, dividing tough perennials, and dozens of other landscape tasks.

I also love my soil knife.  Mine’s a little different than the one I linked to, most notably because of the Day-Glo Orange handle (I rely on neon colors to keep my tool replacement costs reasonable). If you’re planting bulbs, annuals, 4″ perennials, or groundcovers- anything too small for a spade- there’s nothing faster. It’s handy for dividing perennials as well.

Wheelbarrows are another worthwhile place to splurge. I bought a cheap one at Lowe’s when we first bought the house. It has a plastic hopper and wood handles, and it is really flimsy. I hate feeling like I’m going to break my tools just by using them. I now buy all-steel wheelbarrows with metal handles. I’m abusing the heck out of my current favorite, and it seems like it’ll last forever. The flat-free tire is the best thing ever, too. You never notice your tire is flat until you go to move a wheelbarrow full to the top with super-loose concrete.

We have a rule at our house: no tool purchases until there’s a valid reason for it. That’s what I love about what I do- there is ALWAYS a valid reason for new tools!

Compost Updates

First of all, I’ve named the compost pet Composta Heep.  We like Thadd because he immediately got the Imogen Heep reference. Second, today was the big flip. I decided bin #1 was full enough, so it was time to fork it all over into bin #2. I’ll continue adding fresh material to #1, while I allow #2 to cook undisturbed except for frequent turnings. So how’s the compost look?

It’s not as far along as I’d like- not surprising, given the cold weather- but good stuff is happening. It mostly has a “good earthy” smell, with the exception of a few pockets that clearly got compressed and were cooking anaerobically. The pile was quite warm in the middle, too. I may get my thermophilic pile yet. I was particularly pleased with the worms. Considering that it’s February, there were a lot of fat, happy worms crawling around the warmth in the bottom half of the pile. This one must be a good 8 to 10 inches long:

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That’s right- not only was I rooting around in decomposing green waste, oohing and ahhing- I ran to the truck to get the camera. Maybe this is why we never get hit up to buy girl scout cookies. Anyhow, the pile is now fluffy and cooking away in bin #2.

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Given the dimensions of the bin, that’s an honest cubic yard of cooking compost. I’m glad we’ve been doing it; especially since we cook a lot of vegetarian food, it’s amazing how quickly the compost bucket needs taken out. Not only does it give us a good sense of what we’re keeping out of the waste stream, but we know we need to cook more if we’re not filling the bucket!

Water- Part 3

Dealing with water where it leaves the property

In Virginia, I’ve seen a few different scenarios for how water exits a property. In a lot of subdivisions, everyone’s backyard pitches into a swale that carries stormwater into a storm drain. Even if the swale is on your property, you’re usually prohibited from altering the grading such that it impedes the flow of water into the storm drain. I’ve had well-meaning clients who wanted to channel everyone else’s runoff onto their lots and create a giant rain garden. On a larger property you might be able to pull this off, but in a typical subdivision lot you may cause a lot of problems for yourself and your neighbors.

In my situation, I live in downtown Culpeper. A portion of my stormwater runoff ends up in the street and flows into the storm sewer. As this water rushes down the street it picks up oil residues and other contaminants, which will strain the wastewater treatment plant. For this reason, our best course of action is to try and catch as much water as we can reasonably use, and slow the flow of the remainder so that it can more easily percolate back into the ground.

I’ve even dealt with an unfortunate situation where all the water from two neighborhoods ended up in my clients’ backyard- they just happened to be the low point in the area. In that situation, there wasn’t a lot we could do except to make certain the land was graded away from the house, and try to reclaim enough of the backyard to make it usable. As tempting as it may be, solving your water woes by pushing the water into your neighbors’ yards is not an option! Be very careful any time you change the grading and drainage patterns of your lot. If you create water problems for someone downstream, it will be your responsibility to fix them.

The important point here is that for decades, we’ve treated stormwater as more of a liability than an asset. Having made it through a particularly tough drought two years ago, I think we have a better appreciation of the importance- and occasional scarcity- of water. Paying attention to how water enters and exits our properties can help us make the best use of it and ensure there’s enough to go around.

Water- Part Two

Estimated reading time: 4 minutes

Dealing with water in the landscape:

So, we’ve successfully moved the water away from the house and into the landscape. Now what? To figure out the best course of action, we need to answer some questions.

  • Is my soil sandy, loamy, or clay?
  • Will the water flow over pavement or planted areas?
  • If planted areas, are they turf? Groundcover? Mulch beds?
  • If paved, is the pavement pervious or impervious?
  • Are there any features that would also be negatively impacted by water?

The best way to determine the makeup of your soil is to have a soil test done. Clay soils become saturated very quickly, and once they do water will stay on the surface. Sandy soils drain very quickly, but you don’t find them very often in our part of Virginia. Loamy soils have high concentrations of organic matter, which is great because they can absorb more water, and will slowly release it as plants needed. This is why during drought conditions, plants in well-conditioned soil will do far better and with less water than plants in poor soil.

The rate that water is re-absorbed can also depend on what is covering the surface. There’s a growing anti-lawn movement in the gardening community, but healthy turfgrass can be a great “sponge” for absorbing stormwater. Groundcovers can also fulfill this need. However, if you have large mulchbeds with only a few plants, you won’t get the same benefit. In fact, you may end up with problems from mulch washing out of the beds in severe storms. As one of my nursery guys says, “mulch is not a groundcover.”

Paved surfaces are a whole other issue. Standard concrete and asphalt will not allow water to penetrate, so the water sheets off the pavement and increases the load on the next permeable surface. Obviously, stone or brick patios set on concrete will do the same thing. A lot of folks mistakenly believe that pavers allow water to penetrate, but this is not true for standard paver installations. The reason for this is that standard practice is to use polymeric sand for the joints. This assists in locking the pavers together and preventing weeds as well as loss of joint sand, but it also causes the pavers to shed water just like a poured slab. Additionally, pavers are installed on a compacted base of what is called crusher run- essentially a mix of large and small aggregate that is mechanically compacted. Very little water would get through this layer.

Paver manufacturers have since come out with pavers that are specifically designed to allow water to pass through larger joints, through the bedding layer, and into the soil. Rather than a tightly compacted, closed bedding layer, the pavers sit on a layer of uniformly-sized large aggregate (typically 3/4″ clean gravel) that allows water to pass through easily. Some of the more readily available manufacturers of pavers in Virginia are EP Henry, Techo-Bloc, CST, Belgard, Nicolock, and Rinox. Unilock also has several options under their Eco-Paver line, but Unilock seems to be just starting to move into our area. It’s a nice looking product, but any time you’re dealing with a paver product- be sure you can get it before you plan a space around it.

It’s also important to consider any other areas in your landscape that could be affected by water. For example, you’ll want to make sure that stormwater won’t be directed into a swimming pool or water feature, as that could drastically impact water quality. Consider your plant beds as well. I have a swath of plant bed that’s just downhill from a drainpipe outlet, and very little will grow there. If I don’t re-route the drainline, I’ll likely end up with an iris garden in that spot.

An excellent way to deal with stormwater and assist with groundwater recharge is to create a rain garden. To do so, you excavate the area to create a basin of sorts, amend the soil to allow water to drain freely, and plant things that will tolerate and even enjoy “wet feet.” Rain gardens can be a beautiful and functional solution to stormwater concerns.

Water- part one

Ah, water. We cry out for you when you’re in short supply, and curse you when you won’t go away. But without you we’re nothing.

Water’s a huge issue in the landscape as well. Traditional stormwater management, at least in the landscape field, has been simple: get water off the property as fast as possible and it’s no longer our problem. Attitudes have changed as more gardeners are trying to use rainwater for irrigation, and we recognize the importance of allowing water to recharge aquifers. When I create a landscape master plan that responds to Virginia’s soils and climates, I address water in the following ways:

  1. Deal with water at the house
  2. Deal with water on the property
  3. Deal with water where it exits the property

Each step deserves its own post. I may as well deal with them in order, as this is how I address them in plan.

Dealing With Water at the House:

It’s amazing how much water falls on our roofs in a storm. According to www.gardeners.com, a light rain on a mere half inch can yield 300 gallons of water on a 1,000 square foot roof. For most homes, this water is collected in gutters, travels down the downspouts, and is deposited right along the foundation- exactly where we don’t want it. Rain barrels are a great way to collect some of this water for use in the landscape, but you can see from the above figure that one or two rainbarrels can’t possibly hold all the water from even a small storm. A properly constructed rain barrel includes an overflow spout. All too often, the overflow goes into a hose that trails along the ground- right where the downspout would empty! So less water is being dumped at your foundation, but it’s still not an ideal solution.

What I prefer to do is run the overflow (or the downspout, in cases where there are no rainbarrels in use) into buried drainpipe that deposits the water downhill and farther out in the yard. We call these pipes “daylighted”: the pipe travels underground and emerges at the end, so the water flows out onto the surface of the ground. This only works if you have a point in your yard that is downhill from your home, but it is the simplest (and therefore the least likely to fail) way to deal with water from your gutters.

There are two commonly used types of pipe for this application. The first is corrugated 4 inch black plastic pipe. It’s the flexible pipe that is sold in big rolls, that is you may have seen used as the legs on hay bale spiders. That is a much better application for this pipe than diverting water. Because it’s flexible it can move with frost heaves, which means there may be sections that no longer flow downhill. Also, the corrugation provides pockets that can trap sediment, pollen, bits of leaves, and all the other funk that can get washed off your roof. Eventually, if enough trash builds up, you can end up with a clogged pipe. The pipe also crushes far too easily for my comfort level. A zero-turn lawn mower can weigh as much as 1,600 pounds- something to think about.

For that reason, I prefer to use 4″ PVC sewer and drain pipe. It’s the white pipe that’s sold in straight 10′ sections at home improvement centers and plumbing supply yards. Water and any debris will just rocket through the smooth walls of the pipe, and it has a crush strength of 3,000 pounds. The best part, in my mind, is that I can install cleanouts at junctions or bends on long runs. If there’s ever a clog, it’s easy enough to open the cleanout and run a snake through the pipe. Properly constructed, you shouldn’t have  any problems with this sort of drain system. Mine has been in place for three years with no issues at all. Living in an old house, I need all the peace of mind I can get.

Once the water’s away from the house, what do we do with it? I’ll discuss that in part two!

Oyster Shell Paths

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In working with a client on a recent project, I specified crushed oyster shells as the path material. It gives the paths the same look as Colonial Williamsburg, it reuses waste materials, and the light color of the shells reflect any available light at night, aiding in wayfinding. I thought it would be a great application for a rarely used product. As it turns out, there’s a reason they’re infrequently used: they are very hard to come by, and the price reflects that.

Apparently oyster shells are not just a trash product. As I discovered, the shellfishing industry takes the shells back out to sea and dumps them. Not to get rid of them in an “out of sight, out of mind” approach, but as a boost to the oyster population. As Joyce Deaton explains on the Cape Fear Pilot’s website:

Baby oysters start out as free-floating organisms, but soon settle to the bottom and attach themselves to hard surfaces. If they can’t find a hard substrate, they die. They’ll grow on pilings and concrete, but their preferred spot is on oyster shells. A mound of shells placed in brackish water with a good tidal flow will soon become an oyster reef, hosting not only the young oysters but algae, worms, barnacles, crabs, minnows and fish. Soon a diverse marine habitat results from the simple act of depositing the shells.

In addition, the filter-feeding oysters make the water cleaner by feeding on plankton and waterborne detritus.

Several states have formal shell recycling programs, and in some cases volunteers bring dump trailers to festivals, oyster roasts, and restaurants to collect shells. In other areas, those who make their living from oysters regard it as a best practice, and bring the shells with them when they head out for the next catch. This is the kind of sustainability I can get behind! It’s given me a whole new appreciation of what I had previously assumed was ending up in landfills. It looks like I’ll be searching for a product that will give me a similar appearance, since the oyster shells seem to end up where they’re needed most.

Part of the reason I posted this is because I think this is a great reason not to be able to use a product I specified. The other reason is because I did some exhaustive searches on Google, trying to track down oyster shells for landscape use. Instead, I got several links for shell recycling programs, and several more of people wanting oyster shell paths but unable to find a source. So if you’re a fellow traveller who came here looking for a source- the best price I found was out of South Carolina, at just under $1,000 per cubic yard plus freight!

Bin There, Done That

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Although to be honest, the bins are only 90% done. I still need to pick up a bit more lumber- 5/4 x 4 to finish off the side slats, and probably two more pieces of 5/4×6 to rip down into my sliding panels for the fronts of the bins. My friend Thadd came by this weekend to help me finish the project, and he agreed that they may be a bit overbuilt: “Those aren’t compost bins, those are compost bunkers.” While I disagree that they can double as a tornado shelter, they’re pretty stout.

Since I had a pressing need for the bins, they’re already in use. The bale of straw sitting to the left of the composter (bunker?) was purchased for Halloween. After just a few rainstorms, it’s started decomposing beautifully. I took a chunk of the bale and spread it around the bottom of the bin. The straw will take a good while to break down- it’s primarily carbon- so it’ll help provide space for air flow under the kitchen scraps. On top of this, I’ve started dumping our kitchen waste. Once the mud dries out a bit, I need to start transferring in material from the old compost heap. That will get added in layers- partially broken down kitchen and yard waste, finished compost, and a little bit of soured straw for air flow. I’ll also mix in my “compost inoculant,” cheap dog food. Alfalfa meal is a great source of nitrogen to kick start the decomposition process, but it’s expensive to buy it from the garden center. It’s a lot cheaper, however, to buy it when it’s the primary ingredient in dog food.

So what can go into the compost pile? Standard practice says that virtually anything can go in except meat and meat byproducts (bone, connective tissue, animal fat), dairy, and anything excessively fatty, like oils or nut butters. Small quantities of vegetable oils or nut butters are ok, but too much will gum up the pile and make it hard for the compost critters (microbes) to do their job. There are some hardcore composters who successfully handle meat and dairy, but I’m reluctant to go there. My bins are on the property line, so if something goes awry and starts smelling funky or attracting vermin, my neighbors will suffer.

Yard waste is also a great source of compost material. I’ve got a backyard full of leaves that I need to mulch with the mower, and they’ll get added to the mix. You could add them whole, but they tend to mat together and form a layer that takes forever to break down. Weeds are an obvious addition, but you need to be aware that if your pile doesn’t get hot enough, you won’t kill the weed seeds. Grass clippings are a great source of nitrogen, but ideally they should be spread out next to the pile to dry out for a few days, then added. Otherwise, you’ll end up with a slimy, smelly, anaerobic mess.

As for branches and clippings from pruning, they should be chipped up before adding to the pile. Otherwise they’ll take a long time to break down. I’m stockpiling all my brush and clippings, since we’ll need stuff that will burn quickly for the oven. Which- that’s the next project!