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Days To Maturity – What Does It Mean?

Days to maturity, or days to harvest, is a number that can be found on most annual flower and vegetable seed packets. What does days to maturity mean? How can you use the number to grow more food and flowers in your garden?

Days to maturity is a very useful tool for selecting the right variety of seed and gardeners, especially  in colder climates, should understand the term. This is even more important if you grow a vegetable garden.

Days to Maturity for tomato varieties, by Robert Pavlis

Days to Maturity for tomato varieties, by Robert Pavlis

Days To Maturity Explained

The terms days to maturity and days to harvest are used interchangeably.

Lets start with a simple definition of the term ‘Days to maturity’. It is the time needed for the plant to reach maturity. That seems simple enough, but it is not quite that simple.

What is maturity? It is a term that is not well defined in plants, but in this case it refers to a point in plant growth where you can either see flowers, in the case of annual flowers, or pick vegetables in the case of vegetable seed. For plants like a tomato, where you can harvest over a long period of time, maturity happens at the point where you can pick your first ripe tomato.

When do you start measuring this time period?

The answer depends on how you start the seed. If the seed is usually planted straight in the garden, like carrot seed, then the time to maturity is the time between planting and harvesting the first carrot. If the seed is usually started indoors and then planted in the garden, like tomatoes, the time of maturity is the time from setting out seedlings to the harvest of the first tomato.

Limitations of Days To Maturity

Days to harvest is a useful number for gardeners, especially for vegetables, but it does have limitations which are important to understand.

Accuracy of Start Time

The above definition of the start time is still kind of vague. What if one person starts the seed directly in the ground, and someone else starts them indoors? Time to maturity will be different for each person.

Accuracy of Maturity

This is also ambiguous. For example, I can pick carrots when they are quite small, or wait until late fall. In my zone 5 garden that is a 3 month spread. For lettuce some people wait until a head is formed, others pick a few leaves every week. Maturity is not well defined.

Location is Important

When Stokes Seed sends a seed pack of the same variety of tomato to me in zone 5, and to someone in zone 7, the package shows the same Days to Maturity number. But zone 7 has much warmer days, especially in spring, and tomatoes grow faster and fruit ripens earlier in warmer weather. Every location has a different value for Days to Maturity, but the seed packet only shows one value.

Cold or Warm Seasons

The last two summers were unusually cool – tomatoes took much longer to ripen since they are a warm weather crop – they grow best in warm weather. Cool weather crops did better and lasted longer than usual.

Days to maturity are affected by the actual weather in any given year. Some crops are more affected than others.

Using Days To Maturity To Select Seed

The actual number on seed packets is not that useful because you don’t know what location the numbers are for. Think of them as rough guides.

Radishes have a value of 30 days, and tomatoes have a value of 65 days. I don’t expect to harvest the crop at exactly 30 and 65 days, but I do know that the radishes will be ready to pick about 35 days before the tomatoes.

Days to maturity is even more useful for selecting a variety. Consider the tomatoes listed in the above table. Sweet 100 tomatoes will be ready to harvest a month before Beefsteaks. If you live in areas with a short growing season it is a good idea to pick varieties that have the smallest days to maturity value. You will be able to harvest sooner, and longer before the frosts of fall kill the plants.

That 140 day melon will just not just in my zone 5 garden so there is no point planting it.

Even if Days to maturity is not accurate for your area, you can always use the value to compare varieties of the same type of vegetable. Beefsteaks will take longer to ripen than Sweet 100s no matter where you live.

Finding Days To Maturity Values

You will find the days to maturity on most vegetable and annual flower seed packets. The value is always given in days.

Most good vegetable seed catalogs will also include the days to maturity number in their description. If yours doesn’t, find a better source for your seed. Stokes Seed is a good online source for seeds, and they show the days to maturity with each vegetable seed description.

Robert Pavlis
Editor of GardenFundamentals.com
I live in southern Ontario, Canada, zone 5 and have been gardening a long time. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

I hope you find Garden Fundamentals an educational site that helps you understand your garden better.

One Response to 'Days To Maturity – What Does It Mean?'

  1. Dave Harris says:

    The variation in days to maturity is directly affected by Growing Degree Days or Heat Units. A comment or two about Heat Units along with this article I believe would be very helpful to most grower.

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