How to Start Tomato Seeds

Start Tomatoes From Seed

“Knowledge is knowing that a tomato is a fruit. Wisdom is knowing not to put it in a fruit salad.”

-Brian O’Driscoll​

For those folks who cannot wait to get their hands in the dirt, spring not only signals the end of a dreary winter but portends the coming summer months of being outdoors and getting some fresh air and sunshine while gardening to their heart’s content.

While gardeners everywhere prep vegetables of all varieties for planting in numerous ways, we want to focus on growing that incredibly versatile staple of nearly every home garden, the tomato.

If you enjoy gardening and especially growing tomatoes from seed, then you understand the excitement the arrival of spring brings for those of us with a love for the outdoors and a green thumb, although admittedly, my thumb runs from light-green to slightly brown at times. Regardless, tomato lovers everywhere, weary of eating store-bought perfectly round, bright red tomatoes with all the flavor of a Dixie cup, realize the time has come to begin growing some real tomatoes!

Starting With Seed

Getting a jump on the season and starting your tomato plant seeds indoors is a fantastic idea for many reasons. If you can start a month or two before planting time, that’s great, but even a few weeks beforehand will be beneficial. You will want to start your seeds six to eight weeks before the last frost date.

When you start with tomato seeds, you have full control over the type of tomatoes you want to grow and are not stuck just growing what is available at your local nursery or garden center. Aside from sheer variety, growing from seed offers other advantages as well.

With tomato seeds, you can discern which plants are the strongest and most healthy as they grow, while weeding out the weak ones. Another advantage is that by starting with seed, you eliminate the chance of bringing home sick or infected plants and introducing them into your garden. Plants you buy may look healthy, but they can still be carriers of diseases and contain microorganisms that can wreak havoc on your healthy plants.

Now that’s not a knock on plant nurseries or other outlets, because most are great, rather it’s just a fact of nature.

Seed Germination

Assuming you’ve chosen your seeds and are ready to get started, let’s look at two approaches to germination.

Many growers like to place one or two seeds into small pots (2-3 inches in diameter) with seed-starting mix about a half-inch deep, water thoroughly, then place them in a sunny spot, such as a sunny window. In a few weeks or sooner, healthy tomato seedlings will emerge. In a few more weeks, these seedlings will become little plants with true leaves. Some recommend placing the small pots with the seedlings on a windowsill. Personally, if it’s still cold out, I feel the temperature on a windowsill can drop too drastically at night, possibly harming the fragile tomato seedlings. Tomato seedlings like warmth.

I germinate the seeds before planting them for two reasons. First off, I’m not wasting time waiting for seedlings to emerge from the dirt that aren’t coming, and second, I can keep the seedlings that show the most plant vigor or good health, the ones that burst forth early with their strong little roots.

Germinating First

Take six paper towel sheets and stack them evenly on top of each other. Place them into a container or baking pan that will hold a little water. Wet the paper towels thoroughly. Place your hand over the paper towels and pour off any excess water. Keep them as wet as possible. Place your seeds on one-half of the wet paper towels, spaced a little, and then fold the other half of the towels over the seeds. Put it in a dark place.

Begin checking on them in a couple of days. Healthy seeds should take only a few days, or less than a week, to hatch and show their root. You can remove the ones that grow a tail long enough to plant. A half-inch tail or longer should be sufficient.

Be sure to check on your germinating seeds daily. Once they start, they grow quickly. Additionally, make sure the paper towels stay wet.

Okay, my seed has a nice tail. Now what?

Growing Medium

Many of us are familiar with your standard peat pellet. It is a small, flattened disc of compressed soil that expands when placed in water and is the perfect medium to begin growing your plants. These pellets are available at any garden center. They even make peat pods specifically for tomatoes.

After you water the discs and they’ve swollen up to their full size, take a pencil or a similar instrument and make a hole about a half-inch deep in the top and place a seed (root down) into the hole. Gently pack the soil around the seed. If you have an artificial light source such a Gro-Lux bulb or an aquarium light, place it over your peat pods containing the seeds, the closer the better (within 3 inches).

When the seedlings are between 2 and 4 inches tall, transplant them into a larger pot with drainage holes. In a few weeks, your seedlings will transform into healthy little plants ready for your garden or greenhouse.

Tip: When introducing your indoor plants to outdoor living, do so gradually. Place the plants in a semi-shaded spot then move them more into the sun as they get used to the intensity of hot sunlight. A few days or so should work.

Ready Set Grow!

Preparing the soil a few weeks in advance of planting is wise to do. This process involves making sure the planting area is free of weeds and that some fresh potting soil with nutrients has been blended into the earth. A 6-inch covering raked in works nicely. This setup allows the tomato plants to focus their energy on growing rather than battling weak soil and weed seeds. Always use sterilized soil.

When to Set Out Your Plants

When it comes time to transplant your young tomato plants, a good rule of thumb is to not plant them outside until at least two weeks past the last frost of spring. This timing ensures a sudden cold snap won’t return to kill them and also allows time for the soil to warm up.

Tomatoes love sunshine and warm weather, so plant them in a sunny place in your garden or greenhouse.

Container Growing

Many people appreciate the convenience that container growing affords them. With this method, you have more control of, or at least easier access to, your plants. In containers that are up off the ground, there is less chance of insect invaders finding your plants while perusing the garden smorgasbord. Additionally, in containers, all nutrients and moisture go directly to the plant, thus removing competition for food and water, not to mention eliminating all that bending over while weeding and nurturing them.

The type of container you should use is up to you. Big pots, terracotta tubes, and grow bags are just some of the options available to you. I touch on feeding your tomatoes a little further down in the article.

Tomatoes like to grow, so it is essential to provide some means of supporting the plant to keep them off the ground. If you prefer a natural material, a bamboo cane or other wooden structure works nicely. For traditionalists, tomato cages are an excellent way to grow.

Watering

When it comes to watering tomatoes, there are nearly as many views and opinions as there are varieties of tomatoes. Here’s what I’ve learned over time.

A lot has to do with where you live, water availability, and what you find works best for you. While genetics account for much of the taste, as some tomatoes just taste better than others, some techniques come into play that may help Mother Nature enhance the flavor.

In the South, where I live, many farmers don’t water their tomatoes except for the first few weeks until the plant is established. In this area, at times, it is impractical to get enough water to the plants regularly when the temperature is above 90 degrees Fahrenheit most of the summer. This problem is only exacerbated by being in an area far from a water source. Moreover, the less you water, the deeper the roots will have to grow to find water. A strong root system generally means a healthier plant.

Studies have shown that when you deprive a tomato of water or dry-farm it, the flavor is enhanced. The science behind it suggests the water-stressed tomatoes produce more sugars, lycopene, and soluble solids, thereby enriching their flavor. While this approach can improve quality, it can reduce the tomato harvest.

Around here, they don’t water again until there is fruit on the plant, and then they water deeply but infrequently. Test this theory for yourself. Set aside a few plants and water them infrequently. Then, juxtapose those plants against the ones you watered more often. See if you can taste a difference.

However, if you can’t stand to see your little friends shriveling up, then go ahead and water them as you will. They are your plants after all.

Feeding Your Tomatoes

While there are numerous fertilizers and plant foods available, plant-specific food seems to work rather well. The food of choice for my tomato-growing friends is a product aptly named Tomato Tone. Tomato Tone works splendidly, but do some research to see if you might like something else better.

When you are transplanting your tomatoes to the garden, throw a little fertilizer in the planting hole first, but be sure and toss in a handful of topsoil on top of the fertilizer. This process ensures the delicate roots don’t come into contact with the fertilizer, as contact could burn the fragile roots at this stage of their growth.

This setup gives them a nutritious start.

After that, wait until the plant has set fruit before fertilizing again. Place the correct amount of plant fertilizer or food, according to the package’s instructions, around the plant and about 6 inches away from the stem. Again, this process is so the roots don’t suffer fertilizer burn.

One of the most vital tips is to be sure to water your plants before you fertilize. After watering your plant, then water the fertilized soil. A well-hydrated plant ensures it won’t absorb too much fertilizer all at once, which can burn and damage young plants.

Two Types of Tomatoes

There are two types of tomatoes: determinate and indeterminate. Determinates are shorter and bushier, and they produce their yield pretty much at the same time. Indeterminates are long, vining plants that bloom indeterminately until frost comes. Cherry tomatoes are typically an indeterminate variety.

Determinate:

Indeterminate:

Pruning

I want to mention that pruning can also be a crucial part of growing delicious and abundant tomatoes. Pruning, essentially, is removing or pinching off sickly, weak, or damaged leaves and branches. 

The leaf removal from pruning triggers the plant to become bushier with new growth. You’ll have shorter and less spindly plants when you prune.

The video below shows you how to prune tomato plants. It’s fun for you and healthy for them.

Tricks of the Trade

Salt as a Flavor Enhancer

Somewhat by accident, it was discovered that watering tomatoes using salt water enhanced the flavor of the ripened tomatoes. Word spread fast. Since then, research has been conducted to determine if this was true or merely wishful thinking. The answer is, Yes! It works! According to one study cited by Lynn Byczynski, tomatoes grown using salt water produced better flavor compared to those grown with regular water.

I don’t have room here to get into the scientific reasons for this occurrence, but suffice it to say, it has been proven to work.

If you’d like to try this method for yourself, there is a company that offers a saline-based product for that particular purpose called SEA-90.

Companion Planting

Companion planting is a term used by gardeners to describe the use of planting companion plants alongside your tomatoes. There are various plants that repel hungry insects from devouring your precious plants. Garlic, basil, and marigolds will ward off pests with their strong smell. You can also harvest the herbs when they are ready.

Plant these varieties and other companions in between your tomato plants. They also ward off whiteflies and other invaders.

You can find a comprehensive list of plants and the insects they repel by searching this site for previous articles on the subject.

You Can Do It!

Admittedly, there is much more information than time and space will allow for me to cover in this article on planting tomatoes from seed. I merely wanted to give you a little insight and a lot of encouragement to grow your own.

While there is a science behind growing tomatoes, it’s not rocket science. There is a lot of common sense involved. All plants need are the three basics: food, water, and sunshine. Beyond that, it just depends on how deep your roots run as to how much science you want to apply when growing tomatoes. Don’t be intimidated by all the scientific aspects.

Tomatoes grow naturally by themselves with a little nurturing and TLC. Be sure to choose the right type of tomato for your geographic location.

The truth is, with just a little practice and experience, you can grow tomatoes that you can be proud of and ones that you, along with your friends and family, can enjoy straight from the garden all summer long.

So, get to planting and have a happy harvest! For a lot more great gardening tips, see our guide on 31 Ways to Make You an Organic Gardening Guru.