16. The Native Meadow Experiment - Installation
It has been over a year in the making, but I’ve finally gotten to a satisfying stage of this experiment – the installation. (see this earlier posting to read about the first few steps.) Due to the very rainy fall we had around here, the soil has been too wet to work with for several months, but we’ve finally had some dry weather that allowed me to get the soil prepared and the plants in the ground.
Soil Preparation
I’ve already discussed the importance of healthy soil and the soil testing I did to determine how to prepare the soil for my native meadow. This started with sheet mulching that I applied almost a year ago, hopefully getting rid of a lot of the weeds, and adding a bit of organic matter. Now its time to improve the health and chemistry of the soil by loosening it and mixing in amendments. I put down a pretty thin layer of cardboard, which is almost entirely decomposed at this point, so I just needed to rake up the mulch layer and store it on the side so that I can amend the soil.
The soil has a fair amount of clay and is definitely compacted, so the first step is to stir it up and break up the chunks to get a finer texture that can easily have the amendments mixed in. The specific recommendation of my soil testing report is to loosen to a 10” depth. This is some hard work, but I can see right away how the soil texture is improved for plant root growth. (It is important to note that some experts recommend a “no-till” soil preparation method in order to preserve soil structure and avoid harming the soil web of living organisms, I hope to explore that more in a future article.)
Once the soil is all loosened up, I’m ready to mix in the amendments. There are many types of amendments that vary depending on the soil you have. In my case the soil testing report gives some specific recommendations “3 cubic yards of nitrogen stabilized organic amendment and 110 pounds of Calcium Carbonate Lime per 1,000 square feet of area.” Most Bay Area soils are going to benefit from additional organic matter which helps counteract the dense clay and adds nutrients. This material, which is usually ground up tree bark or coarse sawdust, needs to be nitrogen stabilized to avoid the leaching of nitrogen from the soil (it can actually suck up nitrogen from the soil if it isn’t). The lime is an amendment specific to my soil, which has a very low pH, added lime will raise the pH to the middle range that plants prefer. I’m also mixing in a packaged all-purpose fertilizer that contains of a whole host of beneficial organisms and nutrients. Mainly I wanted to be sure to get some mycorrhizae in the soil and this mix has 3 kinds of endomycorrhizae, and 5 kinds of ectomycorrhizae, which is great. Without getting too deep into a very large subject, mycorrhizae are a type of fungi that live on plant roots and form a beneficial symbiotic relationship, helping roots uptake nutrients and water and getting food in exchange. There are a lot of other benefits as well – these fungi are a basic part of healthy soil that are often lost in urban areas.
One important thing to understand about soil amendment is that the loosening and adding of amendments does increase the volume of soil you have (sometimes called fluffing), so expect for the planting area to get a little higher. Once you have mixed in all the amendments thoroughly to a 6” depth you lightly compact the soil with a barrel roller or simply by walking on it to even things out.
Plant Installation
Now that my soil is ready its time to put some plants in the ground. See my earlier posting about the plant choices I made, now it is simply a matter of laying them out in the patterns I want, spaced according to mature size, and planting them. I have chosen plants that are small to start with, both because of cost and because they are typically younger and more vigorous, better able to adapt to a new environment. They do need to be treated pretty gently during planting and kept watered because they start with such a small root mass.
Once the plants are in, a thick bark mulch layer should be added, typically 3” deep, but tapering thinner at the plant base since you don’t want to block new leaves and branches sprouting up from the edges of the base of the plant. Mulch is of course critical in your garden for many reasons, such as preserving soil moisture, preventing erosion, adding organic matter to the soil, and blocking weed growth. I also re-installed the expression of the Golden Ratio spiral in my landscape design, using stepping stones for most of it and river rock for the smaller section. It is very satisfying to have these steps complete, now I just need to keep up the watering and watch the grasses grow!
References:
Designing California Native Gardens, by Glenn Keator and Alrie Middlebrook
Handouts and Notes from my attendance at the California Native Grass Association’s workshop: Using California Native Grasses in the Water-Conserving Landscapewww.cnga.org
Creating a California Native Meadow by David Amme, as published in Grasslands, A publication of the California Native Grass Association.
