What does the new USDA Frost Zone Map mean to you?

You may have been gardening your whole life and never knew that your corner of the country is in a zone. A plant hardiness zone that is. If you live in the United States of America like I do (and you may having something equivalent outside of the USA), then you will come to know, as your vegetable gardening experience continues to grow, that the country is broken into plant hardiness zones.

Plant hardiness zone designations represent the average annual extreme minimum temperatures at a given location during a particular time period. They do not reflect the coldest it has ever been or ever will be at a specific location, but simply the average lowest winter temperature for the location over a specified time.

These zones appear on a map of the US that is distributed by the United States Department of Agriculture. The last time a zone map was released was back 1990 and the zones were created using temperature data from a 13 year period (1974 to 1986).

The USDA believes they have improved upon the original map with new data. There are now 13 zones as opposed to 11, and the new zones are now divided into “A” and “B” zones using 5 degree Fahrenheit differentials.

According to the USDA, “Compared to the 1990 version, zone boundaries in this edition of the map have shifted in many areas. The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States. This is mostly a result of using temperature data from a longer and more recent time period (1976 - 2005).”

Large posters of the new map will no longer be available for purchase. The USDA website at USDA.gov has an interactive map that users can click on down to their exact location and give them detailed plant starting dates.

For example, on the old map, New Jersey, where I am from, was split into zones 6 & 7. Now there is 6a, 6b, 7a and 7b with all 4 zones being spread throughout the entire state. My zone went from 7 to 7a (ironically the same exit off the turnpike {inside joke for New Jersians}), however the temps and cold frost dates are virtually unchanged for my area.

So what does this mean for your growing adventures? Well, the more detailed version will allow you to better estimate when to start your plants indoors and of course move them outdoors to avoid any chance of frost. While this new map is more accurate, according to the USDA, you should always take precautions with your plants outdoors as you never know when you will get that one last blast of frost.


About the Author

Mike Podlesny is the author of Vegetable Gardening for the Average Person: A Guide to Vegetable Gardening for the rest of us, the moderator for the largest vegetable gardening page on Facebook and creator of the monthly Seeds Club.

Watch the video below to learn more about Mike`s Seeds of the Month Club:

Weather: Keep a Close Eye on Frost Conditions in your Area

Frost is the condition that occurs when temperatures reach a low enough level to turn moisture into ice. Usually you will hear the term frost more so when the overnight dew that gets formed on your front lawn or on your car freezes.

If you do not live in an area affected by temperatures that drop near or below thirty-two degrees then you probably never experienced frost conditions. For those of us that live in areas where you can get frost then you know every well how aggravating it can be sometimes.

You get up early in the morning, go out to your car, put the key into the ignition, turn the car on and you are ready to leave, except the fact that the dew froze overnight and now you have frost on your windows. You can’t see out of them therefore you get out the trusty old ice scraper and start chiseling away at the stuff so you can get on your way.

As annoying as frost can be for your early morning commute it can be devastating to your crops if you are a gardener, especially if you grow vegetables that require stable, warmer temperatures like cucumbers, or peppers.

Frost conditions can literally wipe out your entire garden in a matter of minutes. But there is hope, well for us gardeners anyway; you will still have to scrape away at those windows if you want to drive your car.

The United States Department of Agriculture has a great website (just do a Google search on the name United States Department of Agriculture) that gives you detailed frost maps of the entire country. These maps can tell you when your area will be hit with the first frost of the season and of course the last frost of the season.

If you are an avid gardener such as me, you can use these maps and this information to time your garden just right so that when your plants go into the ground there will be very little chance they get hit with frost. I say very little because you never can fully predict weather conditions. I will take the final frost date for my area and add a week or two to just to make sure. That still gives me plenty of time to have a great garden.

Whether it’s your earlier morning drive or making sure the vegetables in your garden do not get wiped out you should be keeping an eye on the frost conditions in your are. By monitoring the conditions you can be well prepared to handle frost when it occurs.


About the Author

Mike is the author of the book Vegetable Gardening for the Average Person. It is a practical easy to follow book that teaches gardeners everything from composting techniques, aeration and frost conditions, to choosing the right tools and picking the right seeds.

The Affects of Frost on your Vegetables and Plants

Frost forms as a result of the surface of some object being chilled below the dew point of the surrounding air. The dew point is the temperature at which air must be cooled in order to be condensed into water. When the chill point is met crystals form on the surface of the object and appear as ice.

The most common form of frost on vegetation is Hoar Frost also known as Radiation Frost. This occurs when ice crystals form overnight due to drops in temperature and heat loss because objects become colder than the surrounding air.

Many plants can be damaged by the affects of frost and some, such as tomatoes, will die. To know which plants will survive a cold night, refer to the back of the package of seeds that you bought as they have excellent instructions as to temperature ratings.

If you bought your plants already grown from a nursery or garden center then it is best to check with someone there so you do not plant them too early. However in a moment I will talk about protecting your plants in the event an unseasonable frost should occur.

The United States Department of Agriculture has an excellent map on first and final frost dates for various regions of the U.S. They have broken the country down into zones. Find your zone and you will be able to calculate when you should start planting your vegetables.

Even with the best calculations sometimes Mother Nature just doesn’t cooperate. As was the case in May of 2009 when three weeks into the month frost conditions occurred in the southern New Jersey and eastern Pennsylvania regions.

Until there is a consistent level in temperatures you should monitor the overnight conditions in your area which can be easily done by watching your local weather or the weather channel. If you have planted your vegetables and they call for a potential of frost, you can and must take precautions to ensure that they, your vegetables make it through the night.

The best method for protection from frost conditions is the use of plastic milk containers. What you want to do is cut the top of the container off, but not too much so the plant won’t fit, and cover the plants with them. This creates a greenhouse warming affect for your plants. The container traps air which stays a constant temperature, never allowing it to drop below the dew point and create frost for the surrounding plant.

When morning comes and the cool temperatures have subsided for the day, remove the plastic milk containers and let them soak in the sun and air. They should be fine.

For gardeners, frost can be a devastating condition and literally wipe out any growth we might have. But there are remedies, actions and preventions we can implement that will increase our chances of success through frost weather conditions.

About the Author

Mike is the author of the book Vegetable Gardening for the Average Person. It is a practical easy to follow book that teaches gardeners everything from composting techniques, aeration and frost conditions, to choosing the right tools and picking the right seeds.