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The Best Way To Start & Grow Tomato Plants From Seed Indoors – 6 Big Secrets To Success!

Looking for the best way to grow your own tomato plants from seed this year – and have amazing transplants ready for your garden on planting day?

Not only is starting your own tomato plants fun and rewarding, it also allows you to grow the tomato varieties you enjoy most. And even more – to save some serious cash on your plant budget. But perhaps best of all, it gives you the ability to grow extremely strong, healthy and vibrant plants – right from the start!

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

best way to grow tomato plant from seed indoors
Growing your own tomato transplants is fun, rewarding – and can save you some serious cash!

We have been growing nearly all of our tomato plants organically from seed for 15 years now. And it never gets old watching a tiny seed develop into a strong, vibrant plant. But so many shy away from growing their own plants because they think it’s simply too difficult and time consuming. Or, thinking it involves having all kinds of special and expensive equipment.

The good news is that all of those perceived issues couldn’t be further from the truth. In fact, by following a few simple tried and true tricks, anyone can end up with incredible tomato plants that produce amazing tomatoes!

The Best Way To Grow Tomato Plants From Seed

Success with growing your own tomato plants all comes down to following six simple but key tips – the first of which is always starting 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. Of course, that’s if the seed even germinates at all! Heat, humidity and age can really take a toll on seeds -which is why having fresh seeds is a must!

starting tomato plants indoors
One of the biggest keys of all is to always use fresh seeds.

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.

Using The Right Soil For Seeds – The Best Way To Grow Tomato Plants From Seed

Tomato plants are one of the biggest feeders of nutrients from the soil of all vegetable plants. If you start your seeds in poor, lifeless soil, your plants will struggle to grow. Which is exactly why giving your plants good soil right from the start is a big key to success.

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 settling for traditional potting soil all by itself. None of these 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 to it. Trust me when I say worm castings are our go-to ingredient to powering seed starting soil!

They help to create an amazing seed starting soil that is teeming with nutrients. It also helps the seeds retain much needed moisture to help with germination and strong growth. It is truly one of our best secrets for growing incredible transplants. Affiliate Product Link: 100% Pure Organic Worm Castings Fertilizer

fertilizing transplants
100% Worm Castings are ideal for tomato plants. Both when planting seeds, and when planting in the soil outdoors!

Avoiding The Windowsill – The Best Way To Grow Tomato Plants From Seed

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

Seedlings naturally reach for the light. And when they are growing near a window or in a windowsill, they reach so much that the plants become tall and weak with no structure. Instead of the windowsill, use an inexpensive LED or fluorescent shop light placed about one inch 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. Keep the lights on about 8 to 10 hours per day. The result will be tomato plants that have thick stems and strong roots!

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 – it’s important to keep those plants out of the windowsill!

Listen In To Our Podcast Below On Getting Tomatoes Growing Fast!

Fertilize Your Seedlings As They Grow – The Best Way To Grow Tomato Plants From Seed

Even though you have filled your soil with power, that doesn’t mean your tomato plants can’t 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 of foliage.

The best way to feed low and slow is with a diluted mix of all purpose liquid fertilizer – or with 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.

As for when to fertilize, we wait until our seedlings are at about three 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.

If you are using a commercial liquid fertilizer, use it at 1/4 strength to not overpower your tomato plants. Affiliate Link: Farmer’s Secret Tomato Booster Fertilizer (32oz)

Getting Transplants Ready For Life Outdoors – The Best Way To Grow Tomato Plants From Seed

No matter how healthy and strong your seedlings are, it’s 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 away 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.

hardening off transplants
Our tomato plants hardening off outdoors, with the added protection of a wooden wall to help keep them safe from strong winds.

As they continue to grow and conditions allow (warmer, storm-free weather), start keeping your plants out 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 as they try to first adjust to outdoor life.

It’s important to not put your plants out too early. 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.

Plant Your Transplants Deep – The Best Way To Grow Tomato Plants From Seed

Finally, as the threat of frost passes and your soil is warm, it is time to plant your tomato seedlings. Whatever you do, make sure you plant your seedlings deep in the soil! See our article: What To Put In A Tomato Planting Hole – 5 Secret Ingredients To Make Tomatoes Grow Fast!

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

Here is to growing your best tomato plants ever this year from seed – and to a great harvest this summer! Happy Gardening, Jim & Mary

Old World Garden Farms

Jim and Mary Competti have been writing gardening, DIY and recipe articles and books for over 15 years from their 46 acre Ohio farm. The two are frequent speakers on all things gardening and love to travel in their spare time.

As always, feel free to email us at thefarm@owgarden.com with comments, questions, or to simply say hello! You can sign up for our free email list in the subscribe now box in the middle of this article. Follow us on Facebook here : OWG Facebook. This article may contain affiliate links.