Tomato Seedlings Growing Indoors and Transplanting

Tomatoes are the most popular plant to grow in a home vegetable garden! There is nothing like slicing into a juicy, sweet tomato picked fresh from your garden. The taste and nutritional value of homegrown fresh tomatoes are incomparable to store-bought tomatoes. Commercially, tomatoes are often picked green and sprayed with chemicals to ripen! Yuck. Growing tomatoes from seed can also introduce a whole new world of heirloom varieties that are difficult to find elsewhere. Most nurseries only offer about a dozen tomato varieties as plants. When you grow your own heirloom tomatoes from seed you can grow rare varieties that are only available as seeds. You can also save a tremendous amount of money growing and preserving your own tomatoes by canning or dehydrating tomatoes at home.

Heirloom Tomato Harvest Gardening


Heirloom tomatoes grow in so many shapes, sizes, colors, and flavors, how do you pick which tomato variety to grow in your garden? Choosing the best tomato seed varieties is important to get the most bountiful harvest. This means not only choosing a trusted seed supplier with heirloom, non-GMO seed varieties but also knowing which varieties of tomatoes are known for delicious and prolific fruit production. The Back to Eden Gardening Heirloom Tomato Seed Kit is a curated collection including the most popular, best-selling, heirloom tomato seed varieties. We brought together the top 10 best-tasting gourmet tomato varieties all in one package totaling over 225 tomato seeds. 

Heirloom Tomato Harvest Baker Creek Heirloom Seed Festival


Starting tomato plants from seeds is easy and requires the proper soil conditions, warm temperatures, and a little bit of patience. Let’s take a look at how to start tomato plants from seed.


Tomatoes are best to start indoors.The best time to start tomato plants from seeds as starters are about six to eight weeks before you plan on planting them out into your garden. If you get frost in your growing region start growing tomatoes from seed four to six weeks before your last frost date. Transplant your tomatoes two to three weeks after your last frost. You can also search your zip code in a customized planting calendar to find the ideal time to start your tomato seeds indoors. If you start tomato seeds indoors or in a greenhouse you can greatly extend your growing season compared to direct sowing. Starting tomatoes in containers also helps provide the ideal growing conditions


Starting seeds indoors is simple and satisfying. As a Back to Eden Gardener, you are probably accustomed to direct sowing seeds in your rich garden soil and watching them grow amazingly with very little work. It's important to understand that the growing conditions for starting seeds in containers are very different from direct sowing seeds. Seeds can be started in small pots of damp seed starting soil or damp potting soil. The soil you plant your starter seeds in has very different needs than the soil you direct sow seeds in your garden. Indoor seed starters are removed from the outdoor cycle of nature where the beneficial insects, soil microorganisms, sunlight, rain, and wood chips do the work for you. That means starting seeds indoors will require you to make a little more effort to create growing conditions that mimic nature indoors! But don't worry, we will show you how to bring nature's beneficial growing conditions indoors and watch your plants grow abundantly year-round.

Best Tomato Seed Starter Soil Mix Compared

Tomato Seedlings in Bagged Vegetable Planting Mix (left). Tomato Seedlings in Homemade Compost Mix (right).

Best Seed Starter Soil Mix for Tomatoes

A good quality organic seed starting soil mixture retains consistent moisture, ample aeration, essential nutrients and good drainage. Using your native soil or the wrong consistency of ​a ​soil mixture​ for starting seeds in containers​ can lead to stunted growth, lack of germination, or seed rotting. This is why it is very important to get the ​proper ​seed starting soil to have success germinating seeds indoors. ​This winter I ​compared ​the results of planting tomato seeds in three different organic soil mixtures. Our ​three organic soil mixtures included a bagged seed starting mix, a bagged vegetable​ garden planting​ mix, and a homemade soil mix. ​Each soil mixture contained varying ingredients. The ingredients greatly effected the soil moisture retention, drainage and nutrient composition. ​I planted Amish Paste tomatoes in all of the soil​ mixtures​ at the same time ​in the same ​indoor ​growing ​conditions. The ​tomato seedling growth results were astoundingly different. The bagged vegetable mix performed the worst​, it retained too much moisture​ and caused the sprout's growth to be stunted and wither. The bagged ​Seed ​Starter ​Mix grew the second-best​ since it provided aeration and better drainage. The winner was the Back to Eden homemade seed start mix. The homemade compost​ mix recipe contain​ed 60% ​Back to Eden​ screened wood chip compost​, ​30% ​vegetable compost​ and 10% composted horse manure with sawdust​. This tomato plant grew ​by far​ fastest and the ​mature ​plant was the strongest. However, ​since the compost in homemade soil mix​ retain​s more moisture than the bagged start​er​ mix​ it required more attention to frugal watering. For beginner gardeners, I recommend sticking to a high-quality organic seed starting mix. It's worth the investment to ensure your seeds will grow successfully. However, if you​ are an experienced gardener​ ​and have access to aged homemade wood chip compost and vegetable compost you should certainly conduct your own seed starting experiments!

Tomato Seedlings Starting Tomato Seeds Indoors

How to Plant Tomato Seed Starters

In each container, plant two tomato seeds to help ensure​ you have a plant in case a seed does not germinate​. Plant the tomato seeds about three times deeper than the size of the seed​ ​​or 1/8 to 1/4 of an inch (3-6 mm.) deep. Check the seed packet to determine each tomato seed variety's recommended planting depth. Place the seedling containers in a warm place with temperatures that are ideally between 70 to 80 degrees F. (21-27 C.)​ will provide ​the best growing results. If you don't already have a greenhouse or don't live in a sauna temperature home you may need a seed starter heat mat for starting your seeds indoors! If you're a hardcore DIY gardener you can alternatively try setting your seed containers on top of the refrigerator to speed up germination on the heat-generating surface. Once the tomato seeds have germinated, you can take the​m off the heat pad​ if you are using one, ​however you should continue to keep them in a warm space. Thin the seedlings as needed and pinch the tops off after they loose their true leaves to create stronger, stockier plants.

Grow Light Full Spectrum Indoor Gardening

Best Grow Lights Tomato Seedlings

Tomatoes love sunshine and need plenty of bright light to grow indoors. A  south-facing window will work ​as a location for setting your starters ​you have one. Alternatively, a full spectrum grow light placed a few inches (8 cm.) above the tomato seedlings will provide your seeds the bright light they crave. ​My preference is to use the natural sunlight in a greenhouse and​ also use full spectrum grow lights indoors or in a greenhouse. The benefits of the LED grow light are that it is more energy-efficient which means lower electricity bills and you can extend the hours of light your seedlings get during the winter. The best growing light option for you will depend on your climate and the design of your indoor space. Try various methods if you can and compare the results!

Greenhouse Seed Starting Tomatoes

Growing Tomato Seedlings in a Greenhouse

If you live in area with plenty of sunshine year round, consider using a greenhouse to start your tomato seedlings. You can grow your seeds under natural sunlight and naturally harness solar heating instead of using heating mats and indoor grow lights. However, depending on your climate you may need to add a heating source to your greenhouse. Of course you may also want to add grow lights to your greenhouses in some climates.

Haws Water Mister Sprayer Indoor Gardening

How to Water Tomato Seedlings Indoors

Now it's time to mimic nature's rain showers indoors! Tomato seedlings ​need​ consistently moist soil to germinate but not excessively wet soil. ​You'll need to water daily until your seeds germinate. It can take 1-2 weeks for tomato seeds to germinate depending on the conditions. Watering from below, no-work method that ensures the proper soil moisture levels with self-watering containers. Self-watering containers mimic the design of sub-irrigation in nature. The seeding plants draw the moisture stored below the soil up through the roots of the without over-saturating the top-soil. Watering with a mister or spray bottle is another great technique for watering seedlings until the germinate since it provides moisture without overly wetting the soil. Spray the seeds about 4-5 times once or twice per day to keep the soil from drying out. Once your seeds sprout and grow leaves you can switch from a mister to watering with a watering can to ensure the water penetrates down to the roots of the plant.

Best Organic Fertilizer for Vegetable Gardening

How to Fertilize Tomato Seedlings Indoors

What's missing from the equation of bringing nature indoors​... building soil fertility​​! In nature organic matter is constantly shedding from plants and trees and regenerating the soil with nutrients along with the help of microorganisms, fungi and animals. In Back to Eden Gardening growers help build soil fertility with no-till arborist wood chip mulch or other organic mulches combined with organic growing principles. Arborist wood chips constantly input nutrients into the soil as they decompose, reducing the needs for fertilizer. However, when starting seeds indoors you'll need to regularly supplement the soil fertility on your own until the seedlings get strong enough to transplant into your garden. Wait until your seedling has grown a set of true leaves to start fertilizing.​ The true leaves will look more like what the plant's leaves look like when mature.​ ​Once the tomato seedlings have a set of true leaves you can give them quarter-strength water-soluble​ organic​ fertilizer. Every 2 weeks add fertilizer ​again ​​as needed.​​ ​We can't recommend more highly the results of Neptunes Organic Liquid Tomato Fertilizer. Since it is a liquid and made of clean organic ingredients it is more readily available for young plants to absorb. Liquid fertilizers also can permeate into the soil and mulch more easily than dry mixtures. ​At the stage of beginning to fertilize you can also optionally add a light layer of wood chip mulch or coco coir on top of your soil, slightly away from the base of the plant to help retain moisture and nutrients. ​Mulch will also help prevent the top of your seedling soil from hardening and preventing water drainage as it bakes under the growing light. Don't add mulch before seeds have germinated and slightly matured.

Greenhouse Growing Tomato Seedlings

Problems Growing Tomato Start Seeds Indoors

What are some of the common problems and solutions with growing tomato seeds indoors? ​If your tomato seedlings get leggy, they are growing tall and not producing many leaves, this means that they need more light. You can move your light source closer or increase the amount of light the tomato seedlings are getting​ by relocating it​. If your tomato seedlings turn purple, they need ​more ​fertilizer. Apply the quarter-strength organic tomato fertilizer again. If your tomato seedlings suddenly fall over, they have damping off which means they are suddenly dying often due to fungal disease in the soil. In this case, you may have watered too much or your soil was not a healthy seed starting ideal mixture. Growing tomatoes from seed is a fun way to add some unusual variety to your garden. Another issue with starting seeds indoors can be the plants ability to build resistance to elements like wind. Blow on the plant tops or gently run your fingers across the plant occasionally to help mimic wind and build the plants strength.​ Now that you know how to start tomato seeds, a whole new world of tomatoes is open to you.

Tomato Gardening Grow Your Own Fresh Food

How to Transition Tomato Seedlings Outdoors​

If you live in area that gets frost, transplant your tomatoes two to three weeks after your last frost. You can also search your zip code in a customized planting calendar to find the ideal time to transplant your tomato seeds outdoors. Tomato seeds should take six to eight weeks growing indoors before they are transplanted outdoors. They will usually be at least 4-5 inches tall and have developed large leaves and a strong stem before they are ready to be transplanted. If you plant becomes root bound before its time to plant outdoors you can transplant it into a larger container to continue growing indoors until your weather permits. 

Tomatoes must be hardened off before they are transplanted into the garden. This means planning for a period of transitioning the plants to the outdoor climate conditions. After any threat of frost has passed, set the tomato plants in your garden near where you plan on planting them. If you have cold nights, set the starter plant outside during the day and bring it inside at night for the first few days. Allow them to harden off, sitting outdoors in your garden, for about 1 week before planting. Where you plant them should be a warm, sunny location in your garden that is ideally somewhat protected from strong winds. To help tomato seedlings become sturdier, you can remove them from the containers and lay them on their sides, covering the roots with soil and leaving the top of the plant exposed. After a couple days, the tomato tops will begin to grow upright. This allows the plants to adjust to wind and shelter themselves while they adapt and strengthen.

Tomato Starters Growing From Seed

How to Transplant Tomato Seedlings in a Garden

To transplant tomato plants in a Back to Eden Garden move the wood chip mulch layer away from the soil in the area you are going to plant. Using a rake or gloved hands, pull back the wood chip mulch layer to expose about a 6'' x 6'' square foot of the soil below. This will make planting easier without mixing a ton of wood chips into the hole. Using a garden trowel dig a hole just large enough for your transplant container to fit in. Placing your hand over the top of the container, tip the container upside down and squeeze the sides to easily remove the starter. Use your hand to gently roughen up the surface of the roots and help loosen them from a root bound growing habit.

If your soil is fertile, simply place the transplant into the hole and cover it with the displaced soil from the hole. Gently press around the base of the plant to remove air pockets. If your soil is very compact or nutrient deficient, dig the hole several inches deeper and wider than the transplant container. Mix several handfuls of homemade compost or bagged compost into the hole with some of the displaced native soil. 

Tomato Seedling Transplanting in Garden


How to Water Tomato Plants

After transplanting your seedlings they need plenty of water initially. Water the plant deeply to make sure the soil fills the hole on all sides. Use a lead-free hose and a garden hose nozzle on a "shower" setting to avoid washing out your soil or adding in toxins. If you live in an urban area with treated water also consider adding on a garden hose water filter to remove toxic chemicals. Leave the top of your transplant soil flush with the soil level so the stem is not buried too deep. Water every day in dry climates initially. Once the root system is established you may not need to water again. Wood chip mulch reduces watering needs up to 90%. However, you may need to water at least once a week on a deep soak in dry climates without rain. Push your finger into the soil below the mulch and if it has dried out below the top two inches you can water. 

Mulching Tomato Plants Growth

Since tomatoes love lots of soil moisture and are heavy feeders requiring rich soil, mulching the soil around tomatoes is vital for the best results. The best organic mulch for tomatoes is free arborist wood chips in terms of nutrients and soil moisture retention. Add 4-6 inches of wood chips on your soil. Organic seed-free straw or coco coir are also a great mulch options if you can't access wood chips or don't have space for a bulk wood chip delivery. However it does not provide much in terms of nutrients and therefore may require more fertilizing throughout the growing season.

Grow Big Tomatoes Gardening

Best Tomato Fertilizers for Growth and Fruit

Fertilize ​your tomato plants ​with the organic liquid fertilizer every few weeks if your soil is not fertile. Established Back to Eden Gardeners will have​ already regenerated​ deep fertile soil ​conditions ​and​ will​ need to fertilize less frequently. It is super helpful to test your soil if you are not sure what your soil conditions are before wasting money and resources throwing unneeded fertilizers on the soil. That said, a good quality organic tomato fertilizer that is formulated to provide the ideal ratio of essential nutrients will really improve your results when used properly. It's worth the investment to get a clean, concentrated organic liquid fertilizer. A little goes a long way and it improves your soil dramatically, reducing your fertilizing needs in the future. The main four macronutrients that tomato plants need in order to be healthy are nitrogen (N), phosphorus (P), potassium (K), and calcium (Ca). These are known as the N-P-K ratio in fertilizers. In seedlings phosphorus encourages healthy root development. In young plants it provides for strong stems and leaves. During flowering and fruit set phosphorus promotes fruit development and boosts nutrition in tomatoes. Nitrogen provides healthy green leaf foliage and growth. If you see yellowing leaves on your tomatoes they need nitrogen. 

Best Tomato Cages Vegetable Gardening

Tomato Cages and Growing Tomatoes in Containers 

Staking tomatoes with tomato cages also makes harvesting easier, and can help prevent some pests from finding your tomatoes since the fruit will be kept off the ground. It also saves space for small or urban garden spaces. Tomatoes grow well year round in containers and pots even for those without backyard space. However, some people prefer to allow their tomatoes to sprawl and grow without supports. This has the advantage of allowing more even sunlight exposure to the plant and reducing the need for heavy pruning to prevent crowding within your tomato cages. While tomatoes love sun and heat they actually like some afternoon shade to grow their best fruit.

Tomato Suckers Pinching Pruning

Pruning Tomatoes For Better Fruit

Tomato plant leaves tend to grow bushy to create its own shade for the vine. This said, it's important to maintain your tomato plants by periodically pruning and pinching off suckers to improve a tomato plant’s health, vitality, and production. Pinch off the suckers, the stems growing upright out of the "armpit" of two other stems. Indeterminate tomato varieties require more pruning to prevent overgrowth than determinate varieties that stop growing on their own eventually. Don't over prune to avoid too much heat exposure or insufficient foliage for photosynthesis. 

Tomatoes are so fun and easy to grow! Share your tomato gardening growth and harvest journey with us! Grow your own tomatoes with the Back to Eden Gardening Heirloom Tomato Seed Kit today.

Tomato Heirloom Seed Kit


Article photography by Dana & Sarah Films, All Rights Reserved. Article Author Dana Richardson. Dana is a gardener and documentary filmmaker. She has been growing organic, no-till vegetable gardens for over a decade using the Back to Eden Gardening principles. Her passion is to empower people to grow their own food and inspire more sustainable living through video, photography and writing.

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