Tomatoes are a delicate plant when it comes to frost. It is important to start your seeds late enough to avoid a late spring frost, but you want to start them as early as possible so the harvest is done before frost returns in the fall.
Do you wonder when to start tomatoes to give your plants enough time before frost arrives in the fall? How early can you start tomatoes to maximize your harvest?
Tomatoes are typically started indoors 2 months before the last frost in late spring and early summer, and they can be transplanted outdoors into the garden as soon as the danger of frost has passed and night time temperature in your area consistently stays above 50°F/10C.
Knowing when to plant tomatoes is a two-fold question: when to start tomato seeds, and when to transplant them into the garden. Let’s learn the answers to these questions and more.
When To Plant Tomatoes Will Vary Depending On Days To Maturity Needed For The Tomato Varieties
There are hundreds of varieties of tomatoes to choose from, and each one takes a different amount of time to bear and ripen fruit.
How long a particular variety takes to grow is referred to as its “days to maturity” and should be listed on the seed packet.
For most early varieties, this is 55 to 65 days, and long season varieties take between 75 and 100 days. But remember that it will take longer than this before your can actually pick your tomatoes.
A tomato’s days to maturity usually refers to the time from when it is old enough to transplant into the garden until the tomatoes are ready to harvest. So, if the seeds say they mature in 60 days, add on 1 to 2 weeks for germination and 8 weeks of growth before transplant for a total of 130 days from sowing seeds until harvest.
A long season tomato can take upwards of 170 days from when you sow the seeds until you can eat any tomatoes.
So, is your growing season long enough? Count backward from your first frost date in the fall, and make sure you start your seeds early enough so they have time to fully mature. Another important consideration when choosing which tomato variety is the type of plant.
Bush (determinate) varieties generally produce a large harvest of fruits all at the same time, while vine (indeterminate) tomatoes will produce tomatoes throughout the season.
Here are some popular tomato varieties and their days to maturity from transplant:
And the list goes on! Check your local seed company for countless varieties.
Start Tomato Seeds Indoors About Six To Eight Weeks Before The Last Anticipated Frost In Your Area
By starting tomato seeds indoors, the plants will have a head start on the growing season no matter what the weather is doing outside.
Start the seeds indoors about 6 to 8 weeks before you can transplant them outside (for most areas this is around your last spring frost date). Tomato seeds germinate best when the soil temperature is between 25°C and 35°C (68-95°F). They should germinate in 1 to 2 weeks, especially if they have bottom heat from a heat mat.
The seeds can be started cooler than this but germination will be delayed.
Once the seeds have germinated, keep the ambient temperature around 10°C (50°F) for the growing seedlings.
Make sure to provide the young tomatoes with plenty of sunlight to keep them from becoming thin and leggy.
Direct-Sow Tomato Seed Right In The Garden If Your Season Is 4 Months Or Longer Between Frosts
Perhaps you live in a climate where you do not get frost and you can grow tomatoes all year long. If so, many gardeners, including myself, are jealous.
However, most gardens have to contend with some frost so timing your tomato planting is important. If you live in a warm or semi-tropical climate, tomato seeds can be successfully started directly in the garden. Start the seeds early enough so they will have time to mature before the fall frost.
Unfortunately, it is hard for many of us to provide the right germination and seedling conditions early enough in the year and still have enough time for the plants to mature.
Direct sown tomato seeds require the same conditions as seeds started indoors. The ideal soil temperature is around 25°C and 35°C (68-95°F) for germination and the temperature in the garden should be at least 10°C (50°F).
When To Transplant Your Tomatoes Outside
Whether you grow your own tomatoes from seed or buy transplants from the nursery, when you transplant is very important for the young tender plants. Not only are they frost intolerant, but they also do not tolerate cold and their growth be significantly delayed or stunted if the weather is too cold.
Always wait until all danger of frost has passed before transplanting tomatoes into the garden. Most varieties of tomatoes can be transplanted into the garden when night time temperatures remain over 10°C (50°F).
Early season tomatoes are more cold tolerant than other varieties and they can tolerate nighttime temperatures down to 7°C (45°F). Many gardeners prefer to time their tomato transplants based on soil temperature. In this case, wait until the soil has warmed to about 15°C (60°F). Of course, the air temperature cannot dip that low and frost cannot be in the forecast.
Always harden off your seedlings prior to transplant. For more information on hardening off, check out this article, here.
Q. Is it too late to plant thin and leggy seedlings?
The best time to transplant leggy tomatoes is as soon as possible! When the seedlings are leggy, bury the plants up to their first set of true leaves, and the buried, leggy portion of the stem will send out roots. Burying the plants deeper will set them back in their growth, so it is important to get them in as soon as possible.
Q: Can tomatoes handle frost?
No, tomatoes are frost-intolerant, so make sure you plant them after all danger of frost has passed in the spring, but early enough so they will mature before frost returns in the fall.
Q: When is it too late to plant tomatoes?
A: This depends on the variety you are growing. Check the days to maturity for your chosen tomato and make sure you have enough frost free days.
While master gardeners make it look easy, gardening requires a lot of planning. Especially when you are growing sensitive plants like tomatoes.
We often feel we are racing against nature to get our crops in on time, but we are witnessing the wonder of nature as we cultivate a tiny seed into a delicious harvest.
I hope this article has given you enough information to produce a bountiful harvest.
Cameron Jenkins moved from the city to a small farm where he lives with his wife and daughters. The farm is divided between the garden, pastures, hayfields, the start of an orchard, and 13 times as many pets as people. Their farm vision is to grow produce and raise animals in unison with nature. When Cameron is not farming (or writing about it) he spends his time playing with his children, reading, cooking, and napping with his pet pig.