Tomato Plant Care: Seed to Garden (A Complete Guide)
This is an elaborate guide covering all the important aspects of planting tomatoes right from choosing the kind of seed to transplanting your plants into the garden. Use the table of contents below to jump to the stage you want to learn more about:
When to Start Planting Tomatoes from Seed
Before you begin reading this guide, it is important that you understand that the perfect time to plant tomato seeds varies, and it completely depends on your climate. Tomato plants are warm weather plants that originated somewhere in Central and South America and were traditionally cultivated by native Americans before spreading across the globe. Today, they are available in a multitude of varieties.
The Perfect Soil Temperature for Tomato Plants
Germination: Tomato seeds germinate best at constant soil temperatures of around 70 - 80 degrees Fahrenheit (21 - 27 degrees Celcius).
Seedlings: Young tomato seedlings, just after germination and until they have 2 - 3 new leaves, prefer temperatures of around 65 degrees Fahrenheit (18 degrees Celcius)
Grown Plants: Tomato plants once transplanted/planted outdoors, prefer warm temperatures. The night time temperature should not go below 55 degrees Fahrenheit (13 degrees Celcius). Lower temperatures make your plant suffer, thereby stunting growth a bit and this ultimately leads to bad fruit yields, or worse the death of your plants.
Seeds Are Usually Germinated Indoors
Tomato seeds are almost always germinated indoors, either in greenhouses, under grow lights, or simply on a sunny window ledge. Some people choose to speed up germination by placing heat mats at the bottom of the container bearing the seeds. This certainly helps but it is not necessary.
Most of your vegetable plants do not need to be started indoors, but tomato seeds are delicate and require a constant soil temperature between 70 - 80 degrees Fahrenheit to germinate and therefore need to be started indoors in many parts of the globe. Germinating indoors also prevents the young seedlings from being eaten by slugs or other creatures in your garden.
If you live in a region with long warm summers you don't need to germinate your seeds indoors, instead, you just need to make sure that the temperature of the soil outdoors is within the requirements as stated above. However, for those of you living in temperate climates, the soil only reaches this temperature sometime mid-summer and by then it is too late to plant seeds outdoors, as the plants won't grow, mature and bear fruit before the first frost.
The Perfect Date to Plant Tomato Seeds
When planting tomato seeds indoors, it is typical to plant the seeds somewhere between 6 - 8 weeks before the date of the last frost. This is also stated on most seed packets if you read the fine print.
But determining the date of the last frost and the date of the first winter frost later in the year is not easy if you haven't been gardening for years. Luckily, for the people in the United States, there are websites to help you out. Check out the Farmers Almanac, or this helpful chart on hardiness and hardiness regions on the Modern Farmer. There are useful resources for other countries too, a simple google search for frost dates in your country or city would suffice.
Do not worry too much about determining the exact frost dates, a few days here and there is not going to ruin your crop, provided you plant outside only once the soil is sufficiently warm.
When Is It Too Late to Plant Tomato Seeds?
Not everyone is fortunate enough to plan their tomato gardens well in advance. Sometimes life gets in the way and we are delayed. If it's already spring, you're going to want to know whether it is too late to plant your tomatoes.
This depends on the time your plant has to grow, right from the date you wish to plant, until the first expected frost date. All you need to do is determine the days to maturity for the variety of tomatoes you intend to plant. If the number of days from the day you plant to the first frost is greater than the days to maturity, go ahead and plant your tomatoes. If you've missed out don't worry too much, look for other seed varieties that require shorter days to maturity and plant those instead. But, if you're extremely late to the party, there's nothing that you can do about it other than learning from your mistakes and planning better for the coming year.
What Kind of Tomatoes Should I Plant
Before we look into the different ways you could plant your tomato seeds, it would be helpful to make sure that you have selected the right kind of seeds to plant. There are different kinds of tomato plants:
Heirloom and Hybrid Tomatoes
The definition of experts tends to vary a bit when it comes to what categorizes an heirloom tomato. Most experts tend to classify tomato variants from the pre-WW2 era as heirloom tomatoes if the plants have not been crossbred since this period. Heirloom tomatoes are grown from seeds of plants that have been passed down through generations and it is usually within a specific geographic area because of certain characteristics that make the plant fir for survival in that region.
All heirloom tomatoes are open-pollinated, that is, they are pollinated freely by insects and not hand-pollinated by man. Heirloom tomatoes can come in different shapes and sizes even on the same plant, unlike hybrids which are usually very similar in shape and size across multiple plants.
Hybrid tomatoes, on the other hand, are plants that are developed by intentionally cross-pollinating different varieties of tomatoes in order to build up plants with the best traits of the parent plants. For instance, the resistance to dry soil of one plant combined with the resistance to disease of another and the offspring of this plant could be bred with another plant that produces a high yield.
Hybrid tomatoes are thick skinned and are designed for transport rather than taste. Therefore, most people have never truly tasted a delicious heirloom tomato. Yes, you can find tasty hybrid tomatoes too, but that's not the norm. Heirloom tomatoes are thin-skinned and extremely flavorful. If you are not sure what to grow, I would recommend a mix of both hybrids and heirlooms.
Determinate and Indeterminate Tomato Plants
Determinate tomatoes usually grow to a limited height, typically around 3 - 4 feet high. These plants do not grow indefinitely and stop growing once the top buds begin to set fruit. Also, fruit on these plants tend to develop at the same time, and all the fruit on a particular plant typically ripen within a period of 1 - 2 weeks. Since they do not grow very tall, they only require a limited amount of support and are hence ideal for container gardens.
Indeterminate tomato plants, on the other hand, grow for the entire growing season and only stop growing when the weather becomes too cold. They also produce fruit during the entire growing season and can reach heights of up to 12 feet, but 6 feet is usually the average height among these tomato variants. You will find buds, flowers, young fruit and ripening fruit all on the same plant and at the same time. They do require substantial staking for support but are ideal for families who want to have a steady supply of fresh, home-grown tomatoes throughout the summer.
How to plant tomato seeds
To successfully plant tomato seeds you are going to need a few things, such as:
- The tomato seeds
- Containers to plant the seeds
- Soil for germination of the seeds
- Natural or artificial light
1. The Tomato Seeds
When choosing tomato seeds you have the option to use seeds form tomatoes bought from the grocery store, tomatoes from last years harvest, or you could alternatively buy tomato seeds from a store or on the internet. If you are buying seeds, you may want to look for seeds that are resistant to any diseases that are common in your area. Also, you would want to keep in mind what we discussed earlier about heirloom and hybrid tomatoes, and determinate and indeterminate tomato plants.
2. Containers to Plant the Seeds
You're going to want to use small containers, with a depth of at least 3 inches for the germination of the seeds. You could use larger containers too, but I suggest smaller containers as the soil used for germination is a bit different from what the plants would eventually grow in. Moreover, there are benefits to transplanting a tomato plant after germination (you bury the stem a bit to get more roots) which I would personally say is crucial for the future wellbeing of the plant. However, you should understand that this is just a suggestion and not a must.
Just make sure that the container you use has holes at the bottom, if not, make some holes yourself. This prevents the possibility of the soil getting too wet, thereby preventing root rot.
For the seed containers, you can use almost anything. For example:
- Yogurt containers
- Egg cartons
- Cut off milk or juice cartons
- Plastic containers that strawberries and other fruit come in
- Plastic soda bottles
- Plastic cups
- Take away containers and just about anything else
In most of the above cases, you are going to need to make holes in the bottom of the container yourself. Don't forget to place the container on a tray, so that the water seeping out does not damage your furniture, floor or window-sill. Check out these two resources for more ideas on home-made containers for seeds: Preparednessmama and Treehugger.
I do not like to unnecessarily buy stuff when you can recycle what you already have. But if you were looking to buy containers for the germination of your seeds I would recommend by window garden which were a perfect gift for a friend who had just decided to try his hand at peppers. The roots of the tomato plants can penetrate through the container and it could, therefore, be placed directly into a larger container, and then later transplanted into the ground. This is very helpful if you are a new gardener and are scared that you may damage or kill the plant when transplanting the seedling. bio pots
Moreover, these bio pots use natural fiber soil and not peat and have no traces of plastic in them. I have personally tested this out by burning them to see if there was any plastic residue. Also, after using such pots and studying their structure, I make my own using newspaper and some plant fiber.
If you're sowing seeds for a home garden, you're probably not going to be sowing many. But for those of you with large gardens, greenhouses and farms you may want to plant your seedlings in trays. This helps you grow a lot in limited space during the initial germination stage. Check out the video below for guidance on how to plant in trays.
Growing Tomato Seeds in Trays
3. Soil for Germination of Tomato Seeds
Good germinating mixes are fine, uniform, allow for good aeration, are not compact but loose and are free of pests and weed seeds. Also, germinating mixes usually do not need any fertilizer/compost if you intend to transplant as soon as the first true leaves appear.However, if you intend to leave your tomato plants in their initial container for longer than 3 - 5 weeks after sowing, you should seriously think about adding worm castings to the initial mix or alternatively supply liquid fertilizer after the appearance of the first true leaves. If you are not sure what true leaves are, check out the video below.
P.S: Tomato seeds do not require any fertilizer to germinate as the seed contains all the necessary nutrients. It is only after the first true leaves that the plant must begin fending for itself.
Differentiating Between the Dicotyledon and True Leaves
Why You Should Never Use Garden Soil as It Is to Germinate Seeds
Backyard soil is typically too compact and is therefore not ideal for the germination of seeds. It tends to form a hard crusty layer and seedlings find this hard to penetrate and could ultimately die. Also, garden soil is not the best when it comes to aeration and drainage. Lastly, garden soil can harbor diseases and weed seeds. Weed seeds could easily be weeded out, but getting rid of the damping off disease and others is a different story.
Transforming Garden Soil into a Seed Starting Mix
This is not recommended as the best practice, but if you want to be frugal, this is a good option. The rate of a successful germination may be lower, but it definitely is a lot cheaper to use garden soil and homemade compost as a starting mix. But it is vital that you first pasteurize the soil and compost. Check out this article on the best way to pasteurize soil.
Before you begin the pasteurization process, I would recommend that you use a sieve to only allow small particulates of soil and compost to pass through. I would also recommend you add some sand to this mix, if easily available. Now, pasteurize this mix and then add an equal proportion of moistened coconut coir to prevent the soil from clumping up and forming a brick. The coconut coir will help keep the soil loose and aerated. You can buy coconut coir bricks from your local gardening or pet store.
Making a Seed Starting Mix from Sand, Compost & Coconut Coir
Commercial Seed Starter Mixes
If you're a first-time gardener or if you do not intend to plant many seedlings, it is easier, cheaper and quicker to use a commercial seed starting mix such as the which has no added fertilizer to it (it is not a potting mix), but just the perfect blend of ingredients to create a germinating media for your seeds. This was the mix my friend used to plant his peppers, and the pH of the mix was neutral which is a good thing for most seeds. I stole some soil (with permission) to plant a few tomato seeds and I realized that the mix I made at home and this mix produced similar seedlings. When you use this you will have to transplant or add fertilizer after the growth of the first true leaves. Black Gold seedling mix
Some people tend to use the Epsoma SS16 seed starter premium potting mix, but this leads to lower germination rates as it's more of a potting mix than a seed starter mix. But, as stated earlier, if you intend to leave your seedlings in their original containers even after the appearance of their first true leaves, the Epsoma mix is a better option. Just plant 3 - 4 seeds in each container instead of 1 or 2 as you would usually do.
Make Your Own Seed Starter Mix
To make your own seed starter mix, you only need three ingredients or maybe four, depending on whether the mix is solely a seed starting mix or a dual purpose seed starter and potting mix:
- Coconut Coir (2 parts if dry, 8 parts if pre-moistened)
- Vermiculite (1 part)
- Perlite (1 part)
- Screened worm castings to also serve as a potting mix (4 parts)
Coconut Coir is 100% organic and is a by-product of the coconut processing industry. It serves as the base ingredient of your germinating mix. It helps create a light, well-draining media for the seedling roots to grow.
Vermiculite helps retain water and is ideal for germinating seeds and young seedlings that require the soil to be evenly moist but not wet. Adding this ensures that the plant has sufficient water, without you having to water very often. Also, it helps with nutrient retention, if you add any fertilizers in the future.
Perlite is the white pieces that you see in commercial seed start mixes. On its own, it does not hold a lot of moisture. It prevents the compaction of soil and is, therefore, a helpful ingredient to a seed starting mix. It also helps the soil drain quickly (you do not want wet, but just damp soil for your seeds and seedlings) and helps with soil aeration.
To create a seed start mix and also a potting mix, you could either add screened (through a sieve to remove large pieces) compost that is created using the Berkely hot composting method or you can add screened worm castings.
Sowing Your Tomato Seeds
Once you've got your containers, seeds and germinating soil ready you're going to want to fill up your containers with the soil (to the brim). Now make holes into the top of the soil, around a quarter of an inch deep using your finger, a stick or a pencil. Plant two to three seeds in every section/container by dropping seeds into the holes you've just made. When planting two or more seeds, make a hole for each seed, do not place two seeds at the exact same spot. Finally, cover up the seeds with a pinch of new soil filling up the hole. The video below shows you another way to do it, by placing the seeds on the soil and then pushing them in.
Sowing Tomato Seeds in Containers
4. Watering Your Tomato Seeds
It is best to dampen the soil before filling it into the containers because the loose germinating soil settles down and gets compacted a bit on the addition of water. After you've placed your seeds you should water again, to moisten the seed. You could sprinkle a few drops of water on the top ensuring the seed (below the soil) is dampened. Alternatively, you could water from bottom up, as demonstrated in the video above.
Until germination and beyond, you're going to want to make sure that the soil is always moist, not wet. The holes in your container and the coconut coir would make sure that your seeds are never overwatered, so don't worry too much about overwatering at this stage of growth.
Creating a Greenhouse Effect
As you've learned right at the beginning of the article, tomato seeds prefer warm conditions for germination. In case the room with the tomato seeds gets too cold, you could try covering the containers with plastic wrap thereby creating a greenhouse effect. The heat of the sun during the day is entrapped (to some extent) within the wrap. Many people report that this has been beneficial and I can see why. However, if you do this, make sure that the moment the shoots get off the ground, even before the first dicotyledon leaves open, you remove the plastic wrap. Failure to do so would kill your plants due to the lack of oxygen.
5. Providing Adequate Light to Your Seedlings
Tomato plants require sufficient light to grow well. I have personally never had to use grow lights because I always lived in regions with at least 12 hours of warm sunlight on a south-facing windowsill. However, if you do not have the same luxury, it is beneficial if you provide your tomato seedlings with grow lights.
Note: Grow lights are not essential as long as you get at least a few hours of sunlight, but anything less than 12 hours of warm sunlight is not sufficient for your tomato seedlings. If you do not provide artificial light, your plants will not die, but they will not grow well. And a bad growth stage at the beginning of the plants' life may not lead to the best possible crop later on.
Why Grow Lights
Grow lights are perfect for planting seedlings indoors until the plants are mature and the temperature warm enough to move them into the garden. While natural sunlight offers a full spectrum of color, allowing plants to absorb the frequencies they require, grow lights mainly provide light in the red and blue regions which are essential for plant growth.
What Kind of Lights Work Well as Grow Lights?
Home gardeners love using fluorescent lights because they provide a high intensity of light while producing little heat. Also, they are not expensive. You should not use incandescent lights because they produce too much heat which could kill the young tomato seedlings. More importantly, they lack light in the blue spectrum. Light in the blue spectrum helps plants grow green leaves and become stocky. An insufficient amount of blue light results in leggy seedlings, and this is not what you want.
People often discuss full-spectrum lights. These are definitely a better option because they release light in all the seven colors of the rainbow and all frequencies are important for the growth of tomato plants (red and blue are just the most important among them). But these are a bit expensive and in my opinion, fluorescent lights are good enough for the early days, that is, before transplanting into the garden or placing the container outdoors.
To know more about the wattage required (number of bulbs) per square foot if you use fluorescent light bulbs, you could check out this article.
The Distance of the Light from the Plants
Plants are designed to grow towards the light. Seedlings, tend to get leggy if the light source is placed high above them. Therefore, it is suggested that you never place the light source more than 3 - 4 inches above the seedings (or foliage). You are going to have to keep adjusting this as the plants grow.
For How Long Do I Leave the Grow Lights On?
There are different kinds of plants, and tomato plants are long day plants, which means that they need long hours of natural sunlight (14 - 18 hours). However, it is also very important that the plants get periods of darkness (night) for them to be in their natural rhythm. I would suggest you turn off the light in the night when you head to bed and switch them back on when you wake up. Alternatively, you could use an automated system to switch on and off the lights.
The Best Grow Lights for Seedlings
Tomato Plant Germination Time
You probably want to know how long it is going to be until your tomato seeds germinate. There are many factors at play here, right from the variety of the tomato, the soil temperature, the seeds themselves and of course the soil. But in general, expect your tomatoes to rise up from the ground anywhere between 5 to 10 days. Some people have reported that it has even taken them up to two weeks. Make sure you try and maintain the ideal soil temperature for germination which is 70 - 80 degrees Fahrenheit.
Tomato Plant Growth Stages: Video
Transplanting Tomato Seedlings
When we talk about transplanting tomato seedlings, you need to realize that there are two possibilities:
- Transplanting from the germinating container into a larger container
- Transplanting from a container into the garden.
When to Transplant Tomato Seedlings
1. Transplanting from One Container to Another
Let's first look into when you need to transplant your seedling into a larger container. There are a few reasons why you would want to transplant your seedlings from the container where they germinated to a secondary container:
- To provide each tomato plant a container of its own.
- To move it to a larger container because the roots have no more vertical room to grow.
- To move it to a larger container and at the same time bury the plant right up to the first leaves providing the plant the opportunity to develop a better root system.
How to Transplant Tomatoes from One Container to Another
Do not water your tomato plants on the day you wish to transplant them to a new container. The wet soil has the tendency to stick to roots and it is also heavier, increasing the likelihood of the roots breaking while you transplant. This is how I do it:
- I make sure that do not water the plants on the day I wish to transplant.
- I fill up the larger container with the moist potting mix.
- I scoop out a hole in the center of the container so that I can easily lay the tomato plant into the hole.
- I then get the tomato plant(s) out of their original container by holding my fingers around the stem of the plants and flipping the container over (please watch the video below to know how).
- I then separate the plants from each other, while making sure I hold the plant by the leaves and not the stem. You do not have to separate the soil from the roots, if some soil falls off, you have absolutely nothing to worry about. Just make sure that you do not break off the roots.
- I then place the individual plants into their new containers by burying the free stem leaving the first leaves just above the soil (do not let the leaves touch the soil).
- Finally, I water the new plants and place them on the windowsill or maybe in your case under their grow lights.
How to Transplant Tomato Seedlings
2. Transplanting from a Container to the Garden
You only transplant the plant from a container to the garden if it is already around 4 - 5 inches tall and the outside temperature in the night is above 50 - 55 degrees Fahrenheit.
Note: Only transplant a tomato into the garden after you have hardened the tomato plant.
Hardening-Off Tomato Plants
Hardening off tomato plants is the process of acclimating your tomato seedlings or young plants to the outside environment before permanently planting them into the ground or permanently leaving them outdoors (if you grow tomato plants in containers). This process usually happens over a minimum period of a week to two weeks. This is the way I do it:
- I find a sheltered place outside that gets a few hours of direct sunlight. I also try to make sure that this spot does not have very strong winds or cross-winds that could damage the plant.
- On the first day, I take the tomato plants outdoors and place them in this spot for 2 - 3 hours before taking them back inside.
- On the second day, I would leave them outdoors for a little longer and at the same time I also place them in a spot with more hours of direct sunlight.
- Do this for around five days, and then on the sixth day leave the plants outdoors overnight. Just make sure that there is no danger of frost when you do this.
- On the seventh day until the day you plant into the garden, place the plant in a spot that gets around 10 hours of sunlight.
What about people who need to go to work and can't be home to take their plants back in after two hours? In that case, find a spot that does not receive a lot of direct sunlight and let your plants be out until you get home from work. This is not the best way to do it, but you've got no other option.
Hardening is something that you need to do not just for tomato plants, but all plants that were initially grown indoors. This is done to prevent the plants from dying of shock or getting sunburnt from their harsh new environment.
How to Transplant Tomatoes from a Container into the Garden
It is crucial that you get the first steps right when planting your tomatoes in the garden. This is especially important if you are growing an indeterminate variety, as they need a very strong foundation. Follow these steps and you should be good to go:
- The spacing between plants: First, find out how much space you require around each tomato plant. The seed packets of most suppliers specify the full grown size of the tomato plant. If there is no specification on the packet, you should do your research online. The necessary distance between the base of the two plants is usually specified. If not, figure out what is given to you and do the simple mathematics. Failure to provide sufficient space would result in your plants competing with each other for space and sunlight, the end result being fewer tomatoes.
- Mark the ground: Once you know the required spacing mark the spots on the ground where the tomato plants are going to be placed.
- Dig holes: Dig holes into the ground that are as deep as the container plus the additional bit of the stem you wish to bury. I highly recommend that you bury a part of the stem up to the leaves.
- Obtaining more stem region to bury: If you have a lot of foliage and your plants are tall, I would cut off the bottom leaves on a sunny day and the next day (once the open wound is healed) place the plant into the ground up to the leaves. Make sure that you do not let any leaves touch the soil.
- Staking: Before you actually place the plant into the soil, I would place my tomato stakes into the soil, as this prevents me from damaging the root system.
- Cages: If you decide to support the plant using cages, place the cages immediately after you transplant the plants. Placing at this time rather than when you actually need the support prevents you from damaging any new roots that develop.
- Water the plants: After the successful transplantation of the tomato plant make sure that you provide it with sufficient water.
- Mulch: I end it up with a layer of mulch on the top of the soil.
Planting a Tomato Plant into Your Garden
Caring for Tomato Plants: Frequently Asked Questions
That's it. You've finally got your tomato plants into the garden, or out into the sun in their final containers. But, that's not all, the plants still need to grow and produce fruit. During the growing process, you're probably going to come across some problems. Most of them are caused by following the wrong watering techniques. I, therefore, suggest that you get yourself acquainted with the best watering techniques through the guide I've written.
Why Are My Seedlings Turning Yellow
Tomato seedlings turn yellow for a number of reasons. It could be inadequate watering, compacted soil, attack by pathogens, nutritional deficiencies, a lack of sun or some other issue. It is important that you understand the exact underlying cause of the problem before you try to resolve it. Check out my guide: yellow tomato leaves and how to cure them for guidance in dealing with such issues.
My Tomato Plants Are Growing Too Tall
This is a common question asked by gardeners who grow indeterminate tomato varieties for the first time. These plants just keep growing and growing, that is how it is meant to be. But in many cases, we do not want this to happen. If you allow the plant to keep growing, it is eventually going to outgrow its support and the branch can kink which could damage all the tomatoes growing on that branch. You do have an option though. You could decide how tall you want the plant to be and top off the tomato plant. Watch the video below for the best way to do this.