UPDATE 1/1/24
The 2012 Map was updated in late 2023! So if you have reviewed zones before, I recommend double checking your zone as it might have changed. Many areas are slight to minimum, but I believe Central US and East Coast areas may have had more change in zones.
Knowing your zone is one of the first steps in planning a garden as this will help you know what you can grow in your climate. The USDA has a Plant Hardiness Zone Map and each area is given a number to make it easy. The zones mainly focus on cold temperatures as frosts and freezing impact most plants (although so does high heat).
Here is the USDA Plant Hardiness Zone Map where you can put in your zip code to find your zone.
Once you put your zip code in, you will notice more zoomed in just how many zones can be in one county. Below is the Central Coast of California, and it is quite diverse! There are a lot of influencing factors that impact zones:
Latitude
Elevation
Ocean Influence
Continental Air Influence - North America has its own weather from South America for instance
Terrain - Mountains, Plateaus, Hills, Valleys *Sunset Western Garden Book of Edibles, 2010, pg 12
The climate influences are what create microclimates and each area has their own microclimate. Microclimates can even get down to backyards because each of us have different landscapes that will impact our garden. Obviously zones are not going to get that detailed, but you should note for yourself if you have a garden space that gets a lot of sun, or shade etc. Continuing in zones, let's look at an example of two towns on the Central Coast.
Morro Bay lows are at 30-35F in the winter, zone 10a
Atascadero can get as low as 20-25F in the winter, zone 9a
These towns are 20 minutes from each other, but they have differences of elevation, ocean influence, and mountains/hills. Their zones are not far from each other and a lot of the same plants will grow in both places, but some plants will not.
Okay, so once you know your zone, you can then determine what you can grow as they will be listed on gardening websites, seed packages, and plant tags. A couple of examples:
Potatoes = All Zones
Hass Avocado = Zones 16,17, 19-24
Fuji Apple = Zones 3b-9, 12-16, 18-22
A lot of vegetables and fruits have various zones based on the variety...a Fuji Apple will vary from a Honeycrisp Apple.
Zones are not always listed on seed packets, so I like having books that fill in with that.
Sunset Western Garden Book is a wealth of information on plants...like all plants. It's a huge book, but will help with all gardening needs.
Sunset Western Book of Edibles is another book that helps with planning for vegetables and fruits. It's more condensed and focused on the edibles than the large Sunset Western Garden Book.
Below Picture: Sunset Western Garden Book of Edibles
Another aspect of these books is that they will help you know when to start planting based on the last frost. Last frost can vary based on location and sometimes changes per year, but generally you have a good idea when the temperatures aren't freezing. That helps you plan on starting your seeds inside and/or in the ground. Below the photo is of the Sunset Western Book of Edibles...it shows the best planting months for the various zones.
Hopefully, this gives you some good reading material as this has been a very rainy year in California and can help you start planning for the planting months ahead! Happy green thumbing.
Comments