If you know a gardener, chances are you have heard them say, “there’s nothing like a homegrown tomato.” A cliche is a cliche for a reason and I will attest that there truly is NOTHING like a homegrown tomato. It just tastes different. Sweeter and more tomato-y (yes, a tomato that tastes more like a tomato).
So you’ve decided to trust me when I say a homegrown tomato is better than store bought. So how do you grow successful tomatoes from seed? Maybe you want to buy a seedling and transplant it in your garden? Or, maybe you’ve already purchased a mature tomato plant and just need some guidance to ensure you have a successful crop. This is the first post in a three part series “All About Tomatoes.” I will discuss, in detail: how to start tomatoes from seed; how to transplant and stake your tomatoes; routine maintenance and pest management.
In this post I will answer the fundamental question: how to grow a tomato from seed.
How do you grow tomatoes from seed? Tomato seeds will germinate at 70 to 80 degrees in a moist, nutrient rich soil mix, with good air flow and drainage. To learn more about how to grow tomatoes from seeds, continue reading below.
HOW TO START TOMATOES FROM SEED
To grow tomatoes from seed, you need to consider the following components: temperature, water, soil, container, planting depth, light, air, label organization.
Temperature
The first essential component of starting tomatoes from seed is temperature. Establish where you will start your tomatoes. For some, a sunny window sill or natural heat source works. Growing in a sunny spot depends on how many tomatoes you are growing and how much space you have. You may also opt for a greenhouse. There are a variety of greenhouse sizes suited for your particular outdoor space. Personally, I use an electric heat mat to ensure that my seedlings get constant, even heat. I use this heat mat: MET Certified 2 Pack Seedling Heat Mat, Seedfactor Waterproof Durable Germination Station Heat Mat, Warm Hydroponic Heating Pad for Indoor Home Gardening Seed Starter(10″ X 20″). A standard seed starting tray fits well on the heat mat. In order to provide warmth for your seeds and ensure that they germinate and become seedlings, you need a warm spot for your tomato seeds. You can use a sunny window sill, greenhouse, or electric heat mat. Tomato seeds will germinate in as little as 5 days if kept in a warm spot of 70 to 80 degrees Fahrenheit. At temperatures cooler or warmer than 70 to 80 degrees Fahrenheit, your tomatoes may germinate at slower rates or not germinate at all.
Water
In order for your tomato seeds to germinate, you need to keep them constantly wet and moist. The best way to keep your seeds and soil moist throughout the germination process is with a spray bottle filled with water. I spray the top of each seedling cup or tray daily so that the soil is wet to the touch. It is essential and critically important that you keep your seeds wet at all times. You don’t want it to be swampy though. Once the seed germinates it is important that you keep the seedling moist. The seedling doesn’t have an established root system yet to source water and nutrients like a mature plant readily does.
Soil
The next element under your control is soil. There are a plethora of seed starting soils out there on the market from moisture-soluble coconut husk blocks to plain old potting soil. I’ve tried a lot of them – not all – but a lot of them nonetheless. I’ve had really bad experiences with some and we won’t go down that rabbit hole for the time being. The number one seed starting mix that I use for all my seeds is “DR. EARTH ORGANIC & NATURAL ROOT ZONE® SEED STARTER POTTING MIX” https://drearth.com/product/root-zone-potting-mix/ make sure that is EXACTLY what the package says. Do NOT get the fertilizer. Get the SEED STARTER POTTING MIX. Most nurseries and hardware stores carry this brand. If yours doesn’t, you can purchase it online through their web store. If that still doesn’t work you, find a potting mix specifically catered to seeds. Opt for certified organic, with ingredients that you can read and pronounce. This particular seed mix contains peat moss, perlite, seaweed extract, aloe vera, yucca extract, ecto/endo mycorrhizae and beneficial soil microbes. If you can find a similar potting mix that contains those ingredients, go for it!
Container
You have a lot of choices for the container you choose to start your seeds in as well. The choices for seed starting containers is overwhelming to say the least. I have also tried most – if not all – methods and I’m here to offer what I have found to be the most successful. The best container to grow tomatoes from seed in is a 4 inch nursery pot. I have found that they are large enough for the seedling to become established before having to transplant them to a larger pot or raised bed. I use nursery pots like this one: Plastic Pots for Plants, Cuttings & Seedlings, 4-Inch, 30-Pack. I then place the pots in a tray with a humidity dome lid. I picked mine up from my local nursery and they are very, very similar to the ones found here: Heavy Duty 1020 Trays No Holes and Humidity Dome – 3 Pack. There are many great DIY options out there on Pinterest made from toilet paper cartons, old cans, and much more. I personally have had the most success using nursery pots in a tray with a domed lid. With the nursery pots, it is easy to stay organized and ensure the seedlings have enough space before transplanting.
Planting Depth
To plant your tomato seeds: use a pencil to push a hole in the soil about ¼” and place two seeds in the hole. Gently cover with soil. Spray well with water.
Light
Once your seedling emerges, you need to ensure that it has a constant light source. For some, this may be a sunny window sill, inside your greenhouse, or under grow lights. For me, I don’t have a suitable sunny spot in my home. I also don’t have space for a greenhouse. I’ve opted for grow lights – with an exception. Living in Southern California, I experience some pretty unseasonable Winter and Spring days with sustained temperatures in the 70’s. Unlike the average Southern Californian, I stay attuned to the weather forecasts. On days where I know it will be in the high 60’s to mid 70’s with no wind, I bring my tomato seedlings outside during the day and tuck them back inside at night. On days where the weather is in the below 60’s, I keep my new seedlings indoors under program timer grow lights. You can find grow lights in most hardware stores. You’ll want to opt for a light solution that offers a full spectrum of light. Most packaging will specify the purpose of the grow light.
Air
As soon as your seedlings emerge, remove the domed lid from your seedling tray and ensure that your seedlings get good airflow. Tomato seedlings need air flow and circulation to ensure that they don’t go “leggy.” Seedlings that are “leggy” have growth spurted stems and fall over. In my experience, there is little you can do once this occurs. You can prop them up, you can pray, you can blow air on them, etc. Ultimately, you’re best off just getting them proper air circulation from the get go. To get your seedlings the proper air flow they absolutely NEED:
- open a window with a decent draft for a couple hours in the day
- put a fan on at a distance a couple hours in the day
- put them outside on a nice warm day for a couple hours
Labels / Organization
I learned my lesson here – more than once, twice, even three times. No matter how good you think your memory is, it isn’t. I’m here to tell you that here right now. Label your seeds. I use masking tape and a permanent market. I put the masking tape on the outside of the nursery pot and label the seed, the seed type, and the date that I sowed the seed.
To grow successful tomatoes from seeds you need to consider the following essential elements: temperature, water, soil, container, planting depth, air flow and label organization. Within all of these elements you have choices. The general principles remain the same. To grow tomatoes from seed: tomato seeds will germinate at 70 to 80 degrees in a moist, nutrient rich soil mix, with good air flow and drainage.
TYPES OF TOMATOES I AM GROWING & DATE SOWN:
Here are all the types of tomatoes I have grown from seed this year, the company I purchased them from, and the date I put the seed in the soil.
| Variety | Company | Date Sown |
| Vernazza | Uprising Seeds | 2/23 |
| Galina | Uprising Seeds | 2/23 |
| Black Cherry | Uprising Seeds | 2/23 |
| Green Grape | Uprising Seeds | 2/23 |
| Pinky | Uprising Seeds | 2/23 |
| Moonbeam Cherry | High Mowing | 2/17 |
| Sweet Orange II | Uprising Seeds | 2/23 |
| Summer Sunrise | Hudson Valley Seed | 2/23 |
| Upstate Oxheart | Hudson Valley Seed | 3/1 |
| Yellow Pear | Uprising Seeds | 2/23 |
| Snow White | Uprising Seeds | 2/23 |
| Indigo Apple | Uprising Seeds | 2/23 |
| Goldie | Hudson Valley Seed | 3/1 |
| Ace 55 | Botanical Interests | 1/26 |
| Cuor di Bue | Rhiannon | 1/26 |
| Difmarsher | Rhiannon | 1/26 |
| Currant | Floret Flower | 1/26 |
| Brad’s Atomic | Baker Creek | 1/26 |
| Cherokee | Botanical Interests | 1/26 |
| Black Krim | MIgardener | 1/26 |
| Roma | Baker Creek | 1/26 |
| Pink Boar | Baker Creek | 1/26 |
| Get Stuffed | Baker Creek | 1/26 |
| Cuor di Bue | Botanical Interests | 1/26 |
| Valentine | High Mowing | 1/26 |
| Tommy Toe | MIgardener | 1/26 |
| Black Krim | Botanical Interests | 1/26 |
| Gold Nugget | MIgardener | 1/26 |
| Martino’s | Baker Creek | 1/26 |
| Barry’s Crazy | Baker Creek | 1/26 |
| Cherokee | Baker Creek | 1/26 |
| Cherokee Carbon | High Mowing | 1/26 |
| Carbon | Baker Creek | 1/26 |
| Black Icicle | Baker Creek | 1/26 |
| Purple Bumble | Rhiannon | 1/26 |
| Rosso Sicilian | Baker Creek | 1/26 |
| Mushroom Basket | Baker Creek | 1/26 |
| Dr. Wyche’s | Baker Creek | 1/26 |
| Black Icicle | Rhiannon | 1/26 |
| Lucid Gem | Rhiannon | 1/26 |
| Brimmer | Baker Creek | 1/26 |
| Older German | MIgardener | 1/26 |
| Beefsteak | Botanical Interests | 1/26 |
| Hungarian Heart | Baker Creek | 1/26 |
| Rebekah Allen | Baker Creek | 1/26 |
| Snowberry | Rhiannon | 1/26 |
| Roma BUsh | Botanical Interests | 1/26 |
| Oaxacan Pink | Siskiyou Seeds | 3/8 |
| Champagne Bubbles | Siskiyou Seeds | 3/8 |
| Red Centiflor | Siskiyou Seeds | 3/8 |
| Nebraska Wedding | Siskiyou Seeds | 3/8 |
| Giant Belgium | MIgardener | TBD |
| Yellow Stuffer | MIgardener | TBD |
| Opalka | MIgardener | TBD |
| Black Sea Man | MIgardener | TBD |
| Vintage Wine | MIgardener | TBD |
| Azoychka | MIgardener | TBD |
| San Marzano | Territorial Seed | TBD |
| Red Torch | Territorial Seed | TBD |
| Pineapple | Territorial Seed | TBD |
| Japanese Trifele Black | Territorial Seed | TBD |
| Indigo Blue Berries | Territorial Seed | TBD |
| Costoluto Fiorentino | Territorial Seed | TBD |
| Blush | Territorial Seed | TBD |