Growing your own tomatoes from seed is one of the most rewarding gardening adventures you can have! How to Grow Tomatoes From Seed is a popular choice for gardeners.
We grow tomato seeds indoors to get a head start on the growing season. That head start gives us an earlier harvest.
Plus, when you know how to grow tomatoes from seed, you’ll have access to hundreds of amazing varieties that you’ll never find at the garden center.
I absolutely love starting my tomato seeds each year – there’s something magical about watching those tiny green shoots emerge from the soil. Don’t worry if you’ve never done it before! I’ll walk you through everything step by step, and trust me, it’s much easier than you might think.
When to Start Your Tomato Seeds from Seed
Find out the average last frost date for your area, and then count backwards 6 to 8 weeks. The average last frost date around here is mid May. So working backwards 8 weeks, I know that I should be starting tomato seeds indoors around mid March.
It’s best to start seeds about 4 to 6 weeks before the last spring frost date. Don’t start too early, or you’ll just end up with leggy seedlings and later stunted growth and wilting.
Here in Florida, our timing is totally different from what you’ll read in most gardening books!
Zone 8: Start seeds indoors in early January. Zone 9: Start seeds indoors in late December through early January.
The UF Extension recommends planting in August at the earliest and February at the latest. In my opinion, tomatoes are best planted from September to January to allow for enough cool weather for a full season.
I’ve learned the hard way that starting too early just creates more work for yourself.
This is not an exact science. So don’t sweat the exact date. Aim for approximately 6-8 weeks.
The key is giving your seedlings enough time to grow strong without becoming root-bound before it’s time to plant them outside.
Setting Up to Grow Tomatoes From Seed Successfully
For more gardening tips, check out: My Top 5 Beginner House Plants
You don’t need fancy equipment to grow tomatoes from seed!
A purchased sterile potting mix is optimal for seed starting. It is lightweight and decreases the incidence of disease. Do not use garden soil to start tomatoes.
That’s for two reasons: First, many garden soils have a structure that packs down, preventing little roots from growing. The other thing is that garden soil can harbour diseases that kill young tomato seedlings.
Containers should be about two-inches deep and have adequate drainage. You can repurpose yogurt cups or take-out containers provided that you create holes in the bottom for drainage.
I love using seed starting trays because they make everything so organized, but honestly, any small container will work as long as it drains well.
The magic temperature for germination is key!
Tomatoes germinate best at 65° to 85°F. Tomatoes are a warm-season crop, so setting seed flats or pots on a heat mat promotes rapid germination.
Tomato seeds should germinate within 4-6 days if you can keep the soil temperature around 80º F.
Don’t have a heat mat? No problem!
I place trays on my covered radiators and have great success. Others use the top of the refrigerator.
Planting and Caring for Your Tomato Seedlings
Place two or three seeds into each small container or each cell of a seed starter. Cover the seed with about 1/4″ of soil and gently firm it over the seeds.
I always plant extra seeds because not every single one will germinate, and it’s better to have too many healthy seedlings than not enough!
The seedlings should pop up in about a week. Once the seeds are up, remove the heat source. Move them to a place with strong direct sun or place under grow lights where they will get bright light for most of the day.
An LED grow light or fluorescent shop light kept on for 16 hours a day works best. Temperatures between 50° and 70°F are perfect for growing rugged plants.
The simplest and least expensive is to grow seedlings in a bright window (south facing is best.) If you don’t have a bright window, you can start seeds under lights.
I use simple fluorescent shop lights and they work great – you really don’t need anything fancy when you’re learning how to grow tomatoes from seed.
Keep the soil moist but never soggy.
It’s easy to kill seedlings by overwatering them. Keep the soil moist, but not sopping wet.
When your seedlings get their second set of true leaves, it’s time to thin them out.
Select the strongest, healthiest seedling and use a pair of scissors to snip off the others at the soil line.
Transplanting Your Homegrown Tomato Plants
Before your seedlings can go outside permanently, they need to get used to outdoor conditions.
So we “harden off” seedlings, which simply means we get them used to outdoor conditions. We do this by putting the plants outdoors, in the shade, for a few hours each day. Give them a longer stint in the sun each day, and keep doing this for at least a week.
“Hardening off” is a crucial step in the indoor seed-starting process that you should not skip. It involves introducing seedlings to the outdoor environment to acclimate to direct sunlight, rain, wind, and fluctuating temperatures.
I know it seems like a lot of work, but this step really makes the difference between plants that thrive and plants that struggle.
Here’s something cool about tomatoes –
If you have lanky plants, with more stem than you want, you can bury a lot of that stem. That’s because tomato plants will send out new roots where you bury the stem.
So don’t worry if your seedlings got a bit leggy – you can actually plant them deeper and they’ll develop stronger root systems!
The timing for transplanting varies depending on where you are in Florida.
Florida’s warm climate means that we can plant tomatoes in late winter or early spring when the rest of the country is still shivering in the cold. But since tomatoes are a warm-weather crop, resist the urge to put them in the ground until the danger of frost has passed.
Learning how to grow tomatoes from seed has been one of my favorite gardening skills to develop. Yes, it takes a bit more patience than buying transplants, but the variety selection is incredible and there’s nothing quite like harvesting tomatoes that you grew from tiny seeds! Start small with just a few varieties your first year, and I promise you’ll be hooked. The taste of a sun-warmed tomato that you grew from seed is absolutely worth every bit of effort you put into it.
