Understanding Frost Dates and Zones wallacegardencenter

Understanding Frost Dates and Zones

Jumping the gun on planting may leave you in the weeds! Read our complete guide on frost dates and zones.

Understanding frost dates and zones can give you the upper hand in your gardening endeavors. Knowing your frost dates by zone can help protect your plants and save you plenty of headaches. Stay in the know by reading our guide on the 411 of frost dates and zones.

What is a Frost Date?

Simply put, frost dates mark the span of time where your area is or is not at risk of frost. We have frost dates in both spring and fall. A spring frost date marks the first day you can begin planting things that may have otherwise been damaged by frost earlier. While some trees and shrubs can tolerate some frosty days, many cannot. A fall or autumn frost date marks the beginning of potential frost damage to your plants, although usually, by that time, your plants have finished growing for the year. The spring frost date is most important because it marks the beginning of the planting and growing season. Green thumbs everywhere want to get started and have their best garden yet, but jumping the gun may leave you in the weeds!

What is a Zone?

A grow zone, also known as a hardiness grow zone, dictates what kind of plants can survive in every area of the country. Each plant you buy at a greenhouse or start by seed is categorized by a zone. When selecting plants and seeds, check the zone number to ensure it corresponds to the area you live in. Some plants can withstand a range of different zones, but some are very picky. Not every plant that thrives in Florida will thrive in Iowa, for example. When you look up your grow zone, remember that you can likely also grow plants in one zone lower than you. Most of Iowa is designated as zone 5.

heuchera and hostas in gardenWhat are the Frost Dates in my Zone?

Plant hardiness zones will also help you understand what frost dates correspond with your area. Knowing this can help you plant when your area is past the risk of frost damage. If you plant too early, your new plants could be damaged or killed, especially tender plants like tomatoes, basil, and impatiens. If you wait too long, you will miss the optimal time for planting and may not reap the harvest you were hoping for! If you’re in Iowa, here’s a handy guide for your spring frost dates:

Northern Iowa: May 15

Southern Iowa: May 10

Central Iowa: Between May 10-15

Can I Plant Anything Before the Frost Date?

Frost dates are super important for tender plants susceptible to major frost damage, but some plants can handle the cold. About a month before the spring frost date, you can look to plant some of these cold-hardy species:
  • Most trees and shrubs
  • Perennial flowers
  • Perennial herbs (oregano, mint, thyme, tarragon, rosemary)
  • Cool-season vegetables and herbs (cilantro, lettuce, radishes, kale, broccoli, spinach, cauliflower)
  • Cool-season flowers (violas, poppies, pansies, snapdragons)
  • Roses (particularly the bare-root kind)

planting seedsWhat Else Can I Do Before the Spring Frost Date?

If you’re counting down the days before you can unleash your green thumb into the great outdoors, consider a few ways to prepare for warmer days:
  • Get seeds started, or check on the ones you are cultivating inside.
  • Make sure your yard and garden are cleaned up and ready for the summer months.
  • Get your tools sharpened and ready for gardening, or stock up on essentials!
  • Check your compost and test soil conditions to see if you need to need any soil amendments.

What Can I do After the Fall Frost Date?

The short answer is not much! Or should we say, not mulch? Once the first frost hits in the fall, you’ll notice your annuals and perennials get damaged and die off. It’s the circle of life! The first frost date marks the start of your fall yard clean-up. You can begin pulling up anything you want to get rid of and getting your garden ready for winter. Fall frost dates are much more loosey-goosey than spring dates because nothing is really at-risk. As a general rule of thumb, you can remember:

Northwest Iowa: Last week of September

Southeastern Iowa: End of October

Central Iowa: Second or third week of October

Finally, mark these dates in your calendars and keep them handy for years to come. Knowing your hardiness grow zone and frost dates like the back of your hand will help you feel like a pro gardener, and you’ll have results to match that feeling!

If you’re looking for more information on how to identify and plan around frost dates by zone in Bettendorf, come visit us! We’re always here to help with gardening tips to keep your outdoor space the best it can be.

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