Guide to Frost Dates

For the avid crops farmer, there is one important thing that you might want to take note of and that is the frost dates. Frost dates are the days of the year where there is a 50% chance the temperature will dip below the freezing point and as a result, cause frosting on the ground. There is usually a predicted date in spring for the ‘last frost date’ and a ‘first frost date’ in the fall. It is usually good for farmers to take note of these dates and give some leeway of 2 weeks so that they can harvest their crops in the time between the last and first frost date.

Why do I need to know this?

The importance of doing so is because low temperatures are fatal to plants and these temperatures are lower than 24 degrees Fahrenheit and this is for all plants. There are delicate plants that suffer damages at temperatures that are as high as 29 to 30 degrees Fahrenheit. Knowing all this information can help you to better plan when and when not to plant, and when to harvest so that you can protect your crops from the impending cold. Furthermore, from here, you can also work out what type of plants are more vulnerable to the cold and work on them.

What type of plants can I plant?

The type of plants ranges across a wide spectrum and so do their durabilities. There are plants that are so robust that they can survive any temperature above 24 degrees Fahrenheit. These are the plants that you can get into the ground first and leave to the last to harvest. Some examples of these types of plants are peas, onions, and spinach. Once the soil is penetrable, simply grab a shovel and start planting.

Next are the plants that are slightly less resilient but still can survive between temperatures of 25 to 28 degrees Fahrenheit. These are the plants that should be ideally planted a week or two after the last frost date and harvested a week or two before the first frost date. These plants include kale, mint, cabbage, beets, broccoli, carrots, radishes, cilantro, dill, celery, potatoes, and lettuce.

Finally, these plants require transplanting which means they need to be grown indoors first before being moved out to the field. These are the plants that are most susceptible to frostings and often cannot survive below 29 to 30 degrees Fahrenheit. So, these are the plants that require additional care and should be held onto until there are no threats of the temperature falling below the freezing point before transplanting them into your field. These plants are squash, tomatoes, pumpkins, cucumbers, peppers, basil, beans, melons, corn, and eggplants.

How do I find out what the frost dates are?

There are actually two ways to find out what the frost dates in your area are.

1. The USDA Hardiness Zone Method

The first step to take is to figure out where your hardiness or planting zone is and to do so, simply access the online planting zone map tool on Once you are there, simply enter your zip code to find the specific zone number. Frost dates can vary greatly even if your state is close to another state, so it is essential to find the accurate zone number to find the accurate frost dates for your area. Next, all you have to do is refer to the frost dates list on the same website to determine the dates. Of course, remember our earlier advice, these dates are not fixed so it is always safe to leave a plus-minus of two weeks.

2. The NOAA Climate Station Method

Using the above method is the simpler method however, with its ease, it comes off as less accurate as well. So if you want more accurate results, you can use another tool on the same site that compiles all the information from NOAA’s National Centers for Environmental Information (NCEI). The first step is fairly similar, simply enter your zip code and it will tell you the estimated first and last frost dates of your area. Scrolling down, you will get further in-depth information on the frost dates. There will be estimated dates for not only the 50% chance but also, 10% and 90% chance of frosting. Here, you can utilize this to optimize seeding and harvesting. This tool is the one that we recommend the most, however, if you prefer the simpler version, the first tool is always a good one to use.

Should I depend solely on frost dates?

The answer is no because these dates are merely estimates and they do not take into account various other limiting factors that affect the success of harvesting. One of these factors are things like unusual weather events that crop up, microclimates (whereby things like concrete or steep changes in elevation can affect the climate of your area), humidity, light, soil type. So, while frost dates can provide an estimate on when to prepare your crops, they are not foolproof and you will still have to play by ear in certain situations. To supplement the information that you get from frost dates, another recommendation that we have is for you to conduct in-depth research into the conditions surrounding your area. This is so that you can take note of any unique atmospheric changes that affect your plants. For example, frost dates might tell you certain information about your area but the information can vary due to microclimates, and elevation can change the temperature significantly. Also, plots of land will have different constitutions of soil so there definitely needs to be trial and error to determine the more fertile zones and areas that require more change in the soil.

To end off, frost dates can help you get started on what to look out for when planting and harvesting, but ultimately you are the one that best understands the garden that is uniquely built by you, so trust your gut sometimes!


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