Tomato Growth Stages: How Fast Do Tomatoes Grow? (2024)

So, you have selected your tomato varieties for the season and it’s time to sow seeds. How exciting! Whether you grow tomatoes in raised beds in your backyard or in bags on your porch, it’s an exciting time of the season.

It’s always good to understand the growing process so you can know what to expect and plan for success. It’s also important to know some basic science behind growing so you can pinpoint when something goes wrong and be equipped to troubleshoot issues that might arise.

No matter what type of tomato you choose to grow, it’s important to know about the different growth and ripening stages so you can be the expert of your garden. Keep reading to learn more about tomato growth stages and how long it takes for tomato plants to fully mature.

Growth Stages of Tomato Plants

Tomatoes take 90-140 days to mature, depending upon the variety and other environmental factors, so keep in mind these numbers are just a rough estimate and they will vary.

You can subtract about 30 days if you start them indoors and transplant them, but they’ll still require 60-90 days to fully develop fruit. Be sure to read your seed packets closely, as each company lists information a little differently.

Now that we’ve taken a glance at the 14 stages of tomato growth let’s dig into more detail for each.

Seed Selection

Any tomato plant always begins as a seed. It. is the most basic and youngest stage of the plant. It is quite fascinating to watch a tiny seed become a tall, leafy plant with large red ripe fruits hanging from it! Be patient, as it can take up to 100 days for the seeds to reach that point.

Seed Source & Testing Viability

You always want to be sure you are using seeds with high viability so purchase your seeds from a reputable source. If you save seeds, you’ll want to be sure they have been stored in a cool, dry location.

You can test saved seeds for viability by placing 10-20 in a wet paper towel inside a plastic bag. Place in a warm spot, keep the towel moist and wait a few days until they start to sprout.

You can calculate the germination rate by dividing the number of seeds that germinate by the number of seeds in your bag. Multiply this number by 100.

Example: You start with 10 seeds, and 8 of them germinate.

8 ➗10 = .8

.8 ✖️100 = 80%

This seed batch should have about an 80% germination rate which is pretty good!

Sowing Seeds

Once you know you have good seeds, you are ready to sow them. Gather up all your supplies needed before beginning the process.

Although you can direct seed tomatoes because they take a long time to mature and are very cold-sensitive, I am going to walk you through the process of starting seeds indoors.

Starting seeds indoors gives you a few advantages, including being able to control the environment (temperature, humidity, sunlight, moisture) and selecting the strongest plants to transplant outside, giving your garden the best chance to succeed.

How to Sow Tomato Seeds

Moisten a good quality potting soil or seed starting mix in a tub or bucket. You want it to hold its shape if you ball it up in your hand but not dripping with water. It should not fall apart or be soggy.

If you are sowing quite a few tomato seeds, there are strip trays you can use that will fit a lot in a small area, about 20-25 per strip. Bonus: strip trays easily fit atop a heat mat (if you choose to use one) and will fit nicely under the light when the time comes. Otherwise, you can simply use cell trays or small pots.

Fill your strip trays, cell trays, or pots with your moistened potting medium and tamp it down. This simply means giving a few quick taps on your working area countertop with the cell trays, so the soil compacts down a bit in place.

This will help provide good seed-to-soil contact, which helps allow seeds to retain moisture from the soil and, in turn, improve germination.

This may seem like an unimportant step, but when there is poor seed-to-soil contact, the seed remains dormant longer, leading to lower productivity, possibly rotting in the cell or not germinating at all.

Sowing in Cell Trays or Pots

Take the end of a pencil or your pinky finger to make a small divot in each cell or pot. Add one seed to each divot, attempting to place each seed in the center of the divot.

Then cover all the seeds with more soil and tamp down the tray once more. You want the seeds to be cozy but still have good airflow.

Spritz the tray or pots with water and sprinkle with a thin layer of vermiculite if desired. The vermiculite helps the soil retain moisture which is especially helpful if you are using a heat mat that can dry the soil out.

Sowing in Strip Trays

Take the long edge of one of your fingers and flatten out the soil in each row of earth. Place about 20 seeds per row, evenly spaced and spaced horizontally with the row.

Tamp them down with the edge of your finger, cover them with soil and then tamp them down again as you did with the soil before covering them to ensure good seed-to-soil contact.

Germination

At this point, your seeds should be sown in a cell tray or strip tray. Keep the soil moist by spraying with a gentle mister or a spray bottle. Strip trays can be easily bottom-watered by putting some water in a 1020 tray and placing the strip tray inside.

Just be sure not to fill it too much and waterlog the strip tray. Keep a close watch and remove the strip tray as soon as you see the water reach the top layer of soil.

Ideal germination temperatures are around 70-75°, and light is not necessary for tomato seeds to germinate. At this point, if you are using a germination dome, you can place it atop your tray now. This will help keep in moisture and keep the environment humid.

Timeframe

In ideal conditions, tomato germination will take 5-10 days, variety and seed viability dependent. Tomatoes are heat-loving crops, so placing trays on a heat mat or in a warm area of your home will definitely speed up the process. Just be sure the soil remains moist, as the added heat will cause it to dry faster.

Early Growth

The earliest growth and formation of the earliest leaves happens between days 25-35. As soon as you see sprouting, it’s time to place your trays under a light.

This can be inside a greenhouse, in a sunny window of your home, or under artificial grow lights.

What are Cotyledons?

Cotyledons are often referred to as “seed leaves” as they are present in the seed itself and aid in germination. They provide the plant embryo with the nutrients needed to germinate and push through the soil surface and emerge as a tiny plant.

They can be a bright or pale yellow at first, but once they are exposed to light, these seed leaves turn green. Cotyledons are not considered “true leaves” because they were already inside the seed at the time of sowing.

These cotyledons have served their purpose after a few weeks and often turn yellow and simply fall off soon after a few sets of true leaves have formed.

Furthermore, there are classifications of plants known as monocots and dicots. Monocots (short for monocotyledons) are plants that produce a seed that contains just one cotyledon whereas dicots (short for dicotyledons) are plants that produce a seed that contains two cotyledons. Tomatoes are an example of a dicot and are the most common classification of seed.

True Leaves Form

About two weeks after germination, true leaves will start to form. These leaves will look like small tomato leaves, and since they were not present inside the seed like the cotyledons were, we call them true leaves.

About 3-4 weeks later, when several sets of true leaves are formed, and plants are 3-4 inches tall, they should be “stepped up.” This is simply the act of re-potting the seedlings into a larger space, so they have more nutrients and space to grow their roots.

Stepping Up/Hardening Off Seedlings

Keep in mind that when sowing seeds in strip trays, you should plan to step them up 2-3 weeks later. Otherwise, they will begin to compete and shade each other out. You should pot them up into a size 72 or 50-cell tray. If they are already in cell trays, plan to step them up into small pots to give them a bit more space.

We typically step them up one more time into 4-inch pots to give them one last boost of nutrients and a bit more space. Then we will harden them off for about a week before transplanting them into the ground.

“Hardening off” seedlings is simply allowing them to experience weather and cooler temperatures and adjust to them before being transplanted. If this is not properly done, they could easily go into shock and perform poorly or even die.

Pro tip: We dip our seedlings in a worm-casting extract before transplanting. In a nutshell, worm castings add live organic matter to the soil, help the soil retain moisture, and give your transplants a boost of available nutrients during their early stages.

Vegetative Stage

This is the time period when the plant will start to focus its energies on leaf production. The plant will also start to set aside resources for flower production. The vegetative stages last about 20-25 days.

This is the stage you’ll want to transplant your tomato plants outside once temperatures remain comfortably above 50° as they will not survive a frost. You should plan to use some sort of frost blanket or row cover for the first few weeks of them living outdoors, especially if you live in a cooler region.

If your plants happen to have any flowers on them when they are hardening off, you’ll want to pinch them off before transplanting them so they can focus energies on growing a strong root system in their new home, the ground!

Flowering Stage/Fertilization

The amount of time it will take your tomato plants to flower will depend on the variety you have selected as well as environmental factors such as climate, moisture level, and amount of sunlight it is receiving. For instance, cherry tomatoes are quicker to develop flowers than beefsteak varieties.

In general, plants will begin to flower in 5-7 weeks after germination, and this initial flowering stage lasts 20-30 days. Some growers will pinch the first few flower buds off, so the plant continues its vegetative state.

Soon after you start to see flowers, little green tomatoes will show up where each flower was. The flowers will then naturally fall off, and you should see new flowers beginning to form up the main stem of the tomato plant.

Fruit Production

In the early fruit stages, tomatoes are still green due to their high levels of chlorophyll and are not ready to harvest as they are still receiving lots of nutrients from the plant.

Think of this stage as human adolescence. Lots of growth takes place quickly, so nutrients during this time are essential, mainly calcium, phosphorus, and potassium; for tomatoes that is!

Fruit production takes 20-30 days.

Early Fruiting

The three stages of early fruiting are green, breaker, and the turning stage. Each of these tomato growth stages is important for nutritional and flavor development.

For this reason, harvesting should be held off until the turning stage. There are a number of reasons that a tomato may not ripen, so careful watch is needed during this stage.

Green

One day you’ll walk out into your garden and see that there are full-sized, green tomatoes on the vine. How exciting! But don’t pick them quite yet. These fruits will still be hard, tasteless, and not very nutritious.

Tomatoes can remain in this stage for quite a while if conditions are not ideal. For example, when temperatures rise above 85° for an extended period of time, tomato plant growth comes to a halt as they go into survival mode, reserving water and nutrients.

The reason ripening does not continue at this point is that carotene and lycopene, which are both responsible for giving tomatoes their color, cannot be produced under heat stress.

Pro tip: Later in your season, pick full size green tomatoes before your first frost and make fried green tomatoes or green tomato relish.

Breaker

This is when the color starts to peak out (showing about 10%), and you start planning out all your fresh tomato recipes. It is sometimes referred to as the “first blush” stage.

Interestingly, since tomatoes ripen from the inside, if you cut one open at this stage, you will see the color starting to develop in the innards of the tomato.

Don’t pick them quite yet, as there is still lots of flavor and sugar content to develop.

Turning Stage

A tomato must reach this stage before being harvested for proper ripening off the vine as well as full nutrition and flavor. It is believed to have taken everything it needs from the plant at this point. Color is showing 10-30%.

Mature Fruiting

The three stages of mature fruiting and the final stages of a tomato lifecycle are pink, light red, and red. Most tomatoes take 20-30 days to ripen fully after reaching the full-size green.

Once a tomato reaches its mature size, ripening internally really ramps up with the release of ethylene. Ethylene is responsible for kickstarting pigmentation, so you will start to see the color your tomato will be when fully ripe, whether that’s red, orange, or a gorgeous, marbled heirloom variety.

Pink

This stage is when you can really start to see the true color of the fully ripened fruit, 30-60%. The color will continue to change and deepen over the next 1-2 weeks.

Light Red

You can definitely harvest your tomatoes during this stage, as they are just days away from being completely ripened. You might choose to use these tomatoes for a Caprese salad or on a sandwich because they’ll hold together well and won’t fall apart.

Color is showing 60-90% at this stage, and the flesh may be softened.

Red

This is the stage of full ripeness, sugar content, and color. If there is a fully red (or orange or yellow for that matter) tomato left on your plant, grab it now! Otherwise, it will likely be feasted on by insects or birds, and if left on much longer, it will surely crack.

There is an ongoing debate among tomato growers that discusses whether harvesting at the breaker stage, turning, or light red is best. Remember, what you plan to use your tomatoes for makes a difference in when to pick them.

For example, if you have a whole bushel of fully ripened tomatoes, you might plan to make a big pot of sauce to freeze for later use. Fully ripened tomatoes won’t last long on or off the vine, so you’ll want to use them right away!