Join the Bloom & Grow Garden Club!

Let Maria slide into your inbox twice a month with planty education and inspiration created just for YOU to help you “keep blooming and keep growing” your indoor jungles and spirits (you’ll also be the first to know about upcoming events, launches and other exciting things we are working on!).

Understanding Hardiness Zones, Frost Dates and Microclimates in the Garden, Ep 118

hardiness zones



I’ve always known that Hardiness Zones and Frost Dates are important to planning your outdoor garden… but plant friend, I’ve never quite understood what they were or why they were so important. I’ve gotten as far as typing my zip code into the hardiness zone website, getting my “number” and then pretty much not doing anything with it. As I look to plan my first grown-up garden this summer, I knew I needed help, so I asked Rochelle Greayer, of the renowned garden design website Pith & Vigor, who has years of garden design under her belt to help break all of these important concepts down for us, to better understand our outdoor environments. So many lightbulb moments in this episode, let's dive right in. 


Don't forget to subscribe to the podcast,

so you don't miss the amazing episodes we have coming up!


In this episode we learn:

  • [04:46] What Maria has in store for fellow novice gardeners like her this summer!
  • [05:40] How Rochelle went from flying aircraft and satellites to a full-time garden designer
  • [08:34] What Rochelle loves about garden design—and Maria’s luxury spa biophilic experience
  • [10:00] The many careers you can get into if you want to pursue a plant profession
  • [11:26] Do plants really clean the air in your apartment? Maria discusses this hot topic circulating in the plant community
  • [13:10] The topics that Maria wants to understand about outdoor gardens
  • [13:49] What are hardiness zones? What are the pros and cons of the USDA Hardiness Zones?
  • [17:23] The difference between the USDA hardiness zones and the American Horticultural Society (AHS) Heat Zones
  • [18:39] What does a plant’s hardiness mean?
  • [19:20] Once you know your hardiness zone, how do you apply that information to your outdoor garden?
  • [21:11] Does hardiness matter for annual plants?
  • [21:58] How do frost dates differ from hardiness zones? What are frost dates actually for?
  • [23:10] Why it is important to know frost dates—beware of last frost!
  • [25:54] What’s more important between hardiness zone and frost dates?
  • [29:48] How to plan your garden with your hardiness zone and frost dates information
  • [31:02] Frost date hack: you can extend your growing season inside!
  • [32:31] Understanding how a plant supports itself during growing season
  • [35:06] What are the Sunset climate zones?
  • [36:58] Listener question #1: How much does microclimate affect your predicted garden zones? What is a microclimate?
  • [39:31] How do you know if you have a microclimate in the garden?
  • [41:06] Listener question #2: What methods can be used to push gardening zones, if a plant is hardy just outside your gardening zone?
  • [41:43] Why it’s important to pay attention to the environments in your garden
  • [44:44] Listener question #3: Have the zones changed because of climate change?
  • [46:49] Rochelle’s favorite piece of advice for those who want to try out garden design
  • [48:57] Rochelle’s gardening course for homeowners looking into improving their gardens
  • [50:26] The cool history behind Pith + Vigor’s name
  • [53:23] Maria’s plans for this seed season and how she’s applied this conversation to her garden planning

Mentioned in our conversation:

Thank you to our episode sponsor:

Territorial Seed Company

Thank you Territorial Seed Co for sponsoring today's episode! Territorial Seed Co provides high-quality seeds and plants (over 2000 varieties) that are tried and tested on their 75-acre farm and have a ton of fall varieties for us to try! It's already time to start planning your 2021 garden! For seeds, plants, online garden planner, how-to videos and more visit and use code BLOOM10 for 10% off.

Espoma Organic

For responsibly made, fabulous indoor and outdoor organic soils, fertilizers, pest control sprays, and more, visit to find your local dealer or check out my Amazon storefront of my favorite Espoma products here.



Follow Rochelle

Pith + Vigor: Website 




Follow Maria and Bloom and Grow Radio:

Take the Bloom and Grow Plant Parent Personality Quiz (Get the perfect plants, projects and educational resources for YOUR Lifestyle)

Support Bloom and Grow Radio by becoming a Plant Friend on Patreon!

Instagram and Facebook: @BloomandGrowRadio

Tiktok: @bloomandgrowradio

Subscribe to the Bloom and Grow Youtube Show! /Bloomandgrowradio


Join the (free) Garden Club:

Leave a Reply

Follow along,  plant friends!


Stop wasting money on plants that don’t fit with your lifestyle.

Take the Plant Parent Personality™ quiz, and get curated recommendations for plants, projects, and podcast episodes inspired by your lifestyle to unlock your Plant Parent Potential!

Take the Plant Parent Personality™ Quiz