Another piece of sod: a resource in the landscape?
This is the third of a series of articles that focuses on turfgrass lawns and the challenges that particular landscape feature poses to water-wise transition. The first article discussed the difficulties associated with removal of established turfgrass and the second article focused on how to legally and responsibly dispose of small-scale turf removals and harvest the soil removed through the use of soil screens and sod piles. This rumination (pun intended) is meant to share a few tips on how to make sod work for you as a part of your landscape: either as a feature you want to keep or as the resource for the feature you want to build. The fact that turfgrass is difficult to remove becomes the solution here: lawn becomes a permanent part of your drought-tolerant outdoor design, in one form or another.
SURFACE WATER CAPTURE
It has already been mentioned in a previous article that the easiest way to remove sod without equipment is to cut it out in narrow strips using a round-point shovel or an edger. Often such narrow extrications take place on the edge of an existing garden where roots from desired perennial/shrubs/trees are competing for moisture and nutrients with turfgrass. This can make the grass area patchy and even easier to remove, which is why the slow, seasonal removal of lawn is easiest from the edges where shrubs and perennial gardens are expanding. Furthermore, patchy areas will contain more soil than healthy turf, making it easier to remove the plant/root and dry it out for disposal. Instead of tossing these chunks into a hidden sod pile or transporting them to the landfill, however, consider using such strips right where they are: as a way to build up your land. This is of particular use on slopes, where the unwanted grass is “rolled” down the hill and into an elevated edge: a berm. This is effective in water-wise landscaping because the berm captures and stores surface water flow during precipitation events. Furthermore, this simple technique CREATES soil through the loosening of the earth from the sod, as well as the breakdown of the grass plant itself (very high in nutrients and a favourite food of nematodes). Covering the sod roll with mulch (leaves harvested from existing turf areas, municipal wood mulch, or purchased mulch) will assist with the plant breakdown and will hide the turf roll from the light, which will cause the grass plant (dependent upon light to survive) to perish. Regular weeding keeps the soil loose, malleable, and aerated: before you know it, the berm is part of the bed.
This technique means that there is no transport or disposal of sod – it is, simply, a massage of the landscape into something that can effectively trap water. Using berms for surface water harvest is regularly used in permaculture-based designs in conjunction with on-contour swales, but is an effective and low-cost way for backyard landscapers to transition their yards. This is an extremely effective technique to use with young trees and shrubs: keep “rolling” out the edge, year over year, to just outside the drip line of the growing tree. As your tree expands, so too can your water-wise perennial bed.
PERMEABLE PATHWAYS
Turf is a great choice for a pathway. What may start as an unaesthetic and patchy lawn generally grows into a thick, soft carpet for bare feet due to the turfgrass’s proximity to managed (and irrigated gardens). Furthermore, due to the turfgrass’s sponge-like thatch layer, using it as a pathway creates a very effective, absorptive flood-mitigation system in times of excessive rainfall: this means it will capture and keep the moisture in the landscape (unlike a hardscape pathway).
Because even athletic turfgrass is sensitive to repetitive travel and will eventually show a foot-worn pathway, it is helpful to use stepping stones in areas of high travel. Wide, flat rocks, small pavers, or even bricks can be dug into turf areas to create a visual pathway within the turf that is aesthetically pleasing and functional for walking and for harvesting precipitation.
BED BUILDER
As already mentioned, turfgrass (especially when it’s green and growing) contains nutrients that attract nematodes and other soil microorganisms as it breaks down. For this reason, it is actually a resource for the landscaper to make compost. Perhaps you have heard of, or tried, the “lasagne method” of soil building. This technique involves smothering existing turfgrass with cardboard or newspaper (known as sheet mulching), then building a compost pile on top of the sheet mulch by alternating “brown” carbon sources (leaves, straw, etc) with “green” nitrogen sources (grass clippings, vegetable scraps, composted manure) and capping the “lasagna” with a thick layer of mulch (see “brown”) on top of the pile. This pile can be used in the exact same way as digging sod: either to grow an existing perennial bed from the edges or create an entirely new installation, but instead of removing sod, the effort lies in bringing inputs to stack on top of it, effectively creating a narrow compost pile heavy enough to hold down the sheet mulch so the sod underneath breaks down.
There are endless instructions for this technique (here’s just one): the idea of lasagne bed creation is to use recyclable materials (including turfgrass) to create healthy soil. Sheet mulching can require significant inputs, so there is a conscious decision to be made as to whether it is more or less labour intensive than removing and disposing sod. First, and most importantly, water is required for breakdown of the layered materials, so (like sod removal) it is a difficult process to accomplish during the heat of summer. It is a good fall project, however, as snow can be your moisture source and the freeze/thaw cycle will assist the compost layers to break down over the winter. Furthermore, a compost pile is a protected habitat for hearty nematodes and soil microorganisms to come in and help the turf break down while offering you available plant nutrients with their waste material. Secondly, the area should be level if you plan to use cardboard, as that form of sheet mulch can create an impermeable slide for water, which means it can really dry out the area underneath a slope (even a minimal one: be careful around trees). Attempt to level and deep-water the area before placing a sheet mulch of any kind so that there is ample hydration to break down the materials into soil. Third, a family household and municipal lot rarely produces enough vegetable scraps or other nitrogen-rich inputs to be sufficient for the “green” materials (which is why it is a technique often used in larger property transitions). A great source of low-cost compost for a project like this can be found at the Lethbridge Waste and Recycling center: municipal compost often needs to be “finished” because it hasn’t quite completed it’s transition (finished compost smells like soil – if it has a fetid odor, the waste sources are not yet finished composting). This resource can be too “hot” for direct use in planting but is perfect to add to a project like this as a “green” source. Finally, using unfinished compost or kitchen scraps in your green layers can bring animals into your yard and cause smells. It is often beneficial to cover the pile or new bed area with chicken wire or another protection (a layer of sticks or narrow logs works for cats and raccoons, but not dogs or – gosh – bears). In warmer, wetter climates, these types of beds can break down in one season (this is a common claim) but you should use caution and dig into the bed to find out if the green materials have broken down before you plant into it.
In conclusion, this article was meant to create opportunities for the DIY landscaper with unwanted lawn and a willingness to take their time in transitioning their yard. As transportation, disposal, and garden inputs increase the financial and environmental costs of landscape transition, learning to use existing, on-site resources doesn’t just offer a break for your bank account, it can also assist the health of your backyard. Sod is a highly-nutritious, compostable material that can absolutely assist you in creating the outdoor space you desire. Consider this piece in your own design.
