Skip to Content

How To Grow Tomato Plants From Seed – The 7 Simple Secrets To Success!

Growing your own tomato plants from seed is one of the best ways to ensure your garden will be overflowing this summer with a big harvest of the tomatoes you love most.

Not only is starting your own tomato plants fun and rewarding, it also allows you to grow the tomato varieties you enjoy. Unfortunately, many local stores and greenhouses only carry standard varieties. But when you grow your own, your options are wide open!

From rich, flavorful, meaty beefsteak varieties like Brandywine Pink and Cherokee Purple, to unique and tasty tomatoes such as Mr. Stripey and Tiger Blush, growing from seed allows you the opportunity to fill your garden with incredible color and big flavor.

growing tomatoes from seed
Growing from seed not only gives you more variety options, it also gives you the opportunity to grow amazingly healthy and strong plants.

But even more, it gives you the ability to grow extremely strong, healthy and vibrant plants – right from the start. And best of all, you know what is in the soil, and what has been put on the plants! For us, always knowing the tomatoes we grow from seed are 100% organic is a huge deal.

Unfortunately, when you purchase plants from a nursery or garden center, they aren’t always in the best of shape. When you add in that you really don’t know what sprays or soil additives have been used on the seedlings, it makes growing your own even more attractive.

The Joy Of Growing From Seed

We have been growing all of our tomato plants organically from seed for 11+ years now. It never gets old watching a tiny seed develop into a strong, vibrant plant. Not only is extremely fun and simple to do, it also saves a fortune on tomato plants.

The good news is that the process is actually easier than you might imagine. In fact, by following a few simple tried and true tricks, anyone can end up with incredible tomato plants that produce amazing tomatoes!

vegetable seed sprouting - grow tomatoes from seed
Fresh seeds not only germinate better, they also grow better too. Always make sure you are planting the freshest of seeds, especially when it comes to growing tomato plants.

Growing Tomato Plants From Seed – The 7 Secrets To Success!

#1) Start With Fresh Seeds

A quality plant starts with planting a quality seed. As seeds age, they begin to slowly break down. This is especially true with tomato seeds.

If you plant a seed that has been stored in your garage or basement for three or four years, chances are the plant will struggle. And that is if the seed germinates at all! Heat and humidity really take a toll on seeds. Storing them in a shed, barn, basement or garage subjects them to all kinds of detrimental conditions.

We try to never use seeds that are more than 12 to 18 months old. If we purchase a packet of seeds to plant this year, we will keep the extras in a refrigerator to use again the following year. After that, we discard and start the process again.

#2) Fill Your Seed Starting Soil With Power – Growing Tomato Plants From Seed

Tomato plants are one of the biggest feeders of nutrients from the soil around. If you start your seeds in poor, lifeless soil, your plants will struggle to grow. Giving your plants good nutrition right from the start is a big key to success.

fertilizing cucumber plants
Worm castings are incredible for adding to your seed starting soil. Even if you purchase a high-quality starter soil, adding castings can help power your young seedlings to new heights with a low and slow dose of additional nutrients.

Select a good quality seed starting soil for starting your tomato seeds. It should be light, well draining, and full of good nutrients to power the seedlings early life. Avoid using regular garden soil, top soil, or even heavy potting soil. They simply don’t have enough ready-to-consume nutrients for young seedlings.

We actually make our own seed starting soil by taking a lightweight potting soil and blending in generous amounts of worm castings and fine compost to it. You simply can’t beat worm castings when it comes to starting seeds!

They help to create an amazing seed starting soil that is teeming with nutrients. It also helps the seeds retain much need moisture to help with germination and strong growth. It is truly one of our best secrets for growing incredible transplants. See: How To Create The Perfect Seed Starting Soil

#3) Don’t Grow In The Window – Growing Tomato Plants From Seed

One of the biggest keys to success when growing vegetables from seed indoors is to not grow in a windowsill. Light from even the sunniest of windows simply isn’t strong enough to produce good plants.

window sill seedlings
Growing in a windowsill will produce spindly tomatoes. The light from a window simply isn’t strong enough. The tomatoes end up reaching for the sun, and become leggy and weak.

Seedlings naturally reach for the light. And when they are growing near a window or in a windowsill, they will reach so much that they plants become tall and weak with no structure. Instead of the windowsill, use an inexpensive LED or fluorescent shop light an inch or so over the seedlings.

As they grow, move the lights up to keep them within that 1 inch range. This will allow for slow, steady and compact growth. The result will be tomato plants that with thick stems and strong roots! Keep the lights on about 8 to 10 hours per day.

In the old days, we stacked a few bricks on each side to keep the lights up. Now we use our DIY Table Top Seed Starting Stand to grow a few flats of tomatoes. It makes it easy to adjust up as the plants grow. Whatever you use – keep those plants out of the windowsill! See: DIY Seed Starting Stand

#4) Feed Your Seedlings As They Grow – Growing Tomato Plants From Seed

Even though you have filled your soil with power, that doesn’t mean your tomato plants can use a little extra “juice” when they start growing. The key to feeding young vegetable plants is to feed them low and slow. This allows them to gently grow their roots and their top canopy.

using compost tea
Just like we do with our adult tomatoes, giving a dose of power to young seedlings with worm casting or compost tea will help them grow strong and healthy. You can also use a liquid organic fertilizer, but cut the dose in half for seedlings.

The best way to feed low and slow is with either compost tea or worm casting tea, For us, we stick with worm casting tea. It is the perfect low and slow fertilizer. It also happens to be nearly impossible to over use. You can also use a diluted liquid organic fertilizer if you like, but be sure to water it down to about half strength.

As for when to fertilize, we wait until our seedlings are at about four weeks of age to apply the first dose. We water with the tea as we would normally water the plants. We do this again at the six and eight week mark, and the plants are more than ready for the garden by planting time!

#5) Hardening Off Tomato Plants – Growing Tomato Plants From Seed

No matter how healthy and strong your seedlings are, it is vital to prepare them for life outdoors before planting day. This process is known as hardening off, and it sets the stage for a seamless transition to the garden for your tomato plants.

As your plants begin to reach four to six weeks old, start by taking them outdoors on warm days. Be sure to keep them from harsh winds or weather, but allow them to start receiving natural light from the sun. For the first few days, allow them three to four hours out at a time.

As they continue to grow and conditions allow (warmer, storm-free weather), start keeping your plants out longer and longer. By the six to eight week mark, they can even stay out around the clock as long as frost or bad weather isn’t in the forecast.

This process of hardening off will have them totally prepared for life in the garden. Setting plants out without this “training” can shock and even kill them if the weather begins to turn.

#6) Let The Soil Warm

It is very important your soil in the garden is warm for fast growth. Don’t rush planting day just because your last average frost date has passed. Allow a few warm days to hit the soil before putting your plants in the ground. Cold soil will equal big problems for tomato transplants.

Healthy tomato seedling
Make this the year you grow your own tomato plants from seed!

#7) Planting Day – Plant Them Deep! Growing Tomato Plants From Seed

Finally, as the threat of frost passes and your soil is warm, it is time for planting your tomato seedlings. Whatever you do, plant your seedlings deep in the soil!

By planting them deep, you allow more roots to for under the soil. We usually plant at least two/thirds of the plant under soil. It is a secret we learned long ago that helps protect them and power them later on.

For more on planting day, be sure to check out our article : The 6 Secrets To Planting Tomatoes. Here is to growing your own tomato plants from seed this year, and enjoying a big harvest this summer! Happy Gardening – Jim and Mary.

As always, feel free to email us at thefarm@owgarden.com with comments, questions, or to simply say hello! To receive our 3 Home, Garden, Recipe and Simple Life articles each week, sign up for our free email list that is located in the middle of this article. This article may contain affiliate links.