Once you’ve decided how you want your new garden to function and feel, your next smart step is to evaluate your site.
Understanding your site conditions sets you up to choose plants that are already well-adapted to what your site offers. And this translates into a garden that thrives without a lot of help from you – less work, more enjoyment!
So without further ado, here’s the process I use myself when evaluating a site.
What to Consider
Before choosing plants, you want to consider:
- Hardiness zone
- Soil type
- Existing vegetation
You can find an interactive hardiness zone map on the USDA website here. Just plug in your zip code to get results or choose your state from the drop-down menu at the top of the page.
Now, you may be able to successfully grow plants that are outside of your hardiness zone. If you live in an area with reliably consistent snow cover over the winter, for example, you might well be able to grow some perennials that technically aren’t hardy where you live. Essentially, the snow acts like an insulating blanket.
The same can be true in a sheltered spot – against a south-facing wall, for example – where a plant gets to bask in the wintertime sun and is never in the teeth of the prevailing wind.
But if you want to play it safe, your hardiness zone is a useful data point to know.
Soil is made up of three main components: sand, silt, and clay. The amount of each material determines the texture of the soil.
A sandy soil has large pore spaces and consequently drains quickly (though it may be consistently moist in a low-lying area with a high water table). Conversely, a soil with a high percentage of clay tends to be high in nutrients, but with very small pores, it drains slowly and can compact easily (further impacting both drainage and aeration).
The “holy grail” is loam, which contains a balanced amount of all three. This results in soil that drains well while still retaining a healthy amount of nutrients.
You can have your soil professionally tested (your state university can probably do this for you at a low cost).
But you can also get a good idea of your soil’s makeup by doing a simple test yourself with a mason jar, a bit of dish soap, and some water. There’s a good video to walk you through the process here, if you want to try this method.
It’s also useful to know the pH of your soil, which is a measure of acidity versus alkalinity. I’ve never done this myself because I saw the existing shrub layer of blueberries in the woods when we moved in. Knowing that blueberries only grow in acid soil and seeing that mine were thriving, I could safely conclude that my soil is acidic.
If you have a professional soil test done, that will tell you your soil’s pH. If you prefer the DIY route, here’s a useful post with three ways you can test for pH.
Sunlight and Water
Next, you need to figure out how much sunlight your site receives. Here’s a general rule of thumb:
- Full sun = 6 or more hours of direct sunlight
- Part sun = 3-6 hours of direct sunlight
- Shade = Less than 3 hours of direct sunlight
There are a couple of things to keep in mind, though.
First, make sure you track the hours of sunlight during the growing season. Do this in winter, when the trees have lost their leaves, and what appears to be a site in full sun may prove to be anything but.
Second, if your site receives most of its sun during the afternoon hours, know that this is when the sunlight is most intense. Technically, this site may fall into the “shade” designation, but plants that need shade may not thrive here. You’re better off with plants that are well-adapted to growing in part sun.
Now, regarding water, consider the following:
- Where does water flow and puddle during a good, heavy rainstorm?
- How long does it take for puddles to drain after a storm?
- How will you irrigate your garden while your plants are getting established?
When looking at existing vegetation, first make a note of any invasive species you’re going to have to remove before planting anything else.
Next, look at what else is growing naturally there. There are plants can tell you something about the site conditions. The blueberry experience I shared earlier is an example of this.
Indicator species will vary depending on where you live.
In New England, here are some species that indicate a dry soil:
- white oak
- white pine
- sweet fern
- lowbush blueberry
- spotted wintergreen
Conversely, if you see the following growing naturally on your site, it indicates a wet soil:
- red maple
- sweet birch
- witch hazel
- skunk cabbage
Now, your yard may have both wet and dry areas and if you’re creating a yard map, it’s important to note where they occur. But if you’re just evaluating one section of your yard where you want to start a new garden, your job is a little simpler.
Having done this legwork, you’re getting close to the fun part when you get to put everything together and start picking out plants that fit your garden goals and conditions.
Watch for that in my next post in this series.
Before we say ‘bye for now, though, I’d love to hear from you!
As this garden year winds down and you look back over the growing season, what do you want to add, subtract, or tweak next year?