When To Transplant Tomato Seedlings From Seed Tray {Q&A}

Growing your own tomato plants from seed is a great way to save money and be sure of getting healthy plants. What are the best practices when growing tomato seedlings? When to transplant tomato seedlings from seed tray? How big should tomato seedlings be before transplanting? In this article, we answer these questions and more!

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Transplanting Tomato Seedlings: Q & A

transplanting tomato seedlings: q & a

1. What is the best starting medium for tomato seeds?

It’s best to start out with a sterile commercial seed starting medium. Failing that, a very light and fluffy potting mix is a good choice. Stay away from heavy potting mixes because they retain too much water, encourage fungal growth and discourage high germination rates.

2. How much should you water newly planted tomato seeds?

Before planting seeds, moisten your starting mix to the consistency of a well-wrung-out sponge. Keep the soil slightly moist throughout the germination phase.

3. How deeply should tomato seeds be planted?

You should fill your seed trays or individual containers with your soaked potting medium. Press the medium down lightly and then simply sprinkle your tomato seeds over the surface of the soil. Press the seeds into the soil surface and then add a very thin layer (no more than a quarter inch thick) of light soil mix over the top. Press gently again.

You want to make sure that your seeds have good soil contact on all sides.

4. How can you keep the soil moist during germination?

Keep the soil lightly covered with plastic during the germination period. You can do this by placing entire seed trays or containers inside clear plastic bags or by simply laying plastic film lightly over the surface of the soil. Check daily and spray the surface of the soil with water as needed.

5. What’s the best temperature for tomato seed germination?

Place your prepared seed trays and/or containers in an area where the temperature will stay at about 70°F consistently. Be sure that the soil around the seeds stays a warm, consistent temperature.

You may need to add a heat source below the containers to achieve the best results. During the first few days of germination, your seeds will not need sunlight. You may want to place your containers on top of your refrigerator to maintain a warm, consistent temperature.

6. When do tomato seedlings need sunlight?

In a few days, your tomato seedlings will begin to emerge. When this happens, you should remove the plastic and move your seed trays and/or containers to an area that receives bright, indirect sunlight. When they develop their first set of true leaves, you can move them into direct sunlight.

If you do not have such a location, you can use florescent light or grow lights. Place the containers a couple of inches below the lights to encourage sturdy growth of the young seedlings. Light that is too far away will cause weak stems.

7. How much light do tomato seedlings need?

If your tomato seedlings are receiving natural sunlight, 6 to 8 hours a day will do. If you’re growing them under artificial light, they will need between 14 and 16 hours of light daily. Be sure to turn the lights off after this amount of time has elapsed. Your seedlings will need time to rest.

8. What temperature is best for tomato seedlings?

Once your seedlings begin to grow, they should have daytime temperatures ranging between 60°F and 70°F. Nighttime temperatures should be between 60°F and 65°F. This little dip in temperature overnight will encourage strong, sturdy plants. Excessive heat causes plants to grow leggy.

9. How can I be sure that my tomato seedlings grow strong?

Good air circulation will help your tomato seedlings develop strong, stocky stems. Set up a fan in the room with them. Turn it on low and place it so that it blows an indirect breeze around the area rather than having it blow directly on the plants.

10. How much water do tomato seedlings need?

Throughout their growth period, your tomato seedlings will need to have moist, not soggy soil. Check them daily to make sure that the soil feel slightly damp.

11. How should I water tomato seedlings?

Water very gently to avoid eroding the soil around the roots. Let the water sit out in an open bucket or watering can for twenty-four hours before using it. This will allow it to warm up to room temperature, and any chemicals in the water will evaporate into the air.

12. Do tomato seedlings need fertilizer?

Seedlings will not need fertilizer until they have produced their second set of “true leaves”. If your starting mix has some fertilizer incorporated, it will not hurt anything; however, early fertilizing is not necessary.

13. When should I transplant tomato seedlings from the seed tray?

When your seedlings have developed their second set of true leaves, it’s time to transplant and provide the first fertilizer.

At this time, you can transplant your seedlings into larger containers, or if the weather allows, you can transplant them directly into the garden. Apply half strength fertilizer at this time.

14. How big should tomato seedlings be before transplanting them to the garden?

Although you can transplant them directly into the garden as soon as they developed their second set of true leaves, many gardeners prefer to transition them through a larger pot or container before planting outdoors.

Let them grow to be at least 3 or 4 inches tall before planting outdoors. This gives them a little bit more time to gain strength and resistance against pests, diseases and inclement weather. It also allows the root system to develop and grow stronger.

15. Should I transplant all my tomato seedlings?

If you have simply sprinkled tomato seeds over your seed starting mix, you probably have far more plants than you really need. Cull out the week ones by snipping them at the soil line. Retain and nurture the larger, stronger ones.

16. How do you transplant tomato seedlings?

Whether planting your tomato seedlings in containers or directly into the garden, remember that the parts of the stem that are covered with soil will grow roots. This is a good thing because it ensures that your plant develops a strong, vital root system.

For this reason, you should plant tomatoes into deep containers and/or dig the planting hole deep enough to cover the stem right up to the first set of leaves.

Handle the plants gently throughout the process. Hold them by their leaves rather than by their stems. If leaves are damaged, they can grow back. Damaged stems will kill the plant.

17. What kind of soil should I use to transplant tomatoes?

Surround the plant and the part of the stem that is submerged with the same type of soil mix you used when starting your seeds. If you are planting into a container, purchase a good quality potting soil or container mix for the rest of the soil in the container.

If you are planting directly into your garden, be sure the soil is well tilled, light, airy and well draining. Amend it as needed to attain the correct pH levels and improve nutrient levels. Talk with your county extension agent and have your soil tested to determine exactly what is needed.

18. How do you take care of freshly transplanted tomato seedlings?

During the first week protect your seedlings against harsh sunlight and high winds. Keep their soil consistently moist, and fertilize on a weekly basis with a diluted fertilizer solution.

when to transplant tomato seedlings from seed tray when to transplant tomato seedlings from seed tray

19. When is the ideal time to transplant tomato seedlings?

Most tomato seedlings are ready to move into a larger container when they are three or four inches high and have three or more sets of leaves. Transplant them at least a month before outdoor planting to allow for proper root system development.

20. What cultural conditions are best for tomato seedlings?

Provide tomato seedlings with at least six hours of direct sunlight daily. Daytime temperatures should be between 70 to 80°F, and nighttime temperatures should be above 60°F. Plant your little tomato plants in slightly acidic (pH 6.2-6.8), fertile, loamy, well-draining soil.

21. How long can seedlings be kept in seed trays?

After germination, smaller 1.5″ cell trays can house seedlings for two or three weeks. Larger 2″ trays can accommodate them for up to a month before you’ll need to transplant them. When you do transplant, be sure to thoroughly water both the seedling tray soil and your garden’s soil. This will help ensure good root contact with the soil.

22. How can you prevent transplant shock in tomatoes?

Take care to protect seedlings from too much sunlight before, during and after transplanting. Give them some transition time in a shady outdoor area a day or two before transplanting. Transplant on a cloudy day. Provide a shade cloth in their new setting for several days.

23. Should you transplant tomato seedlings in the morning or evening?

Plant in the evening to give your young plants plenty of time for an overnight rest in their new location. This will help them to acclimate before full sun exposure, reducing the risk of stress.

24. How deep should tomato seedlings be transplanted?

It’s always best to plant tomatoes very deep. Bury about two-thirds of the plant underground. If your seedlings are ten inches tall, you should leave only the top three to four inches above the soil. This will promote the growth of adventitious roots from the buried stem.

25. Should you water tomato seedlings immediately after transplanting?

It’s best to give them a thorough watering the day before transplanting and ensure that your garden soil is also well-watered at the time of transplanting. If you feel that watering the garden soil in advance would be too messy, be sure to provide a thorough watering immediately after transplanting.

26. Can tomato seedlings be transplanted into containers when they are very small?

Container tomato plants should be of the smaller, sturdier varieties (often labeled as balcony or bush tomatoes). These tend to be a bit shorter, and it is fine to go ahead and transplant them into their permanent containers when they reach a height of a couple of inches. Just be sure that they have developed a set of “true leaves” before transplanting.

27. What can you do to be sure your container tomato seedlings stay short, sturdy and stocky?

Prevent leggy growth by providing ample amounts of sunlight. Avoid overcrowding, and be sure to plant your seedlings at the correct soil depth. Water regularly and judiciously. Avoid overwatering.

28. How can you encourage bushy growth in tomato seedlings?

If you have provided your little seedlings with consistent warmth and light, transitioned them properly to their outdoor setting, planted them deeply into good soil, you should be able to expect healthy, bushy growth. Just provide the right amount of water (a couple of inches a week) at soil level, along with a balanced (20-20-20) slow release fertilizer on a monthly basis throughout the growing season. Be sure to prune away damaged, diseased or straggly growth as needed to promote bushy growth.

How To Transplant Tomato Seedlings

10 thoughts on “When To Transplant Tomato Seedlings From Seed Tray {Q&A}”

  1. This article and accompanying video are exactly what I was looking for! My tomato seeds sprouted less than a week ago and are growing quickly. Thanks for the helpful info!

  2. Awesome! Really good communicator. Explained why the extra pot. Loved feature about removing bottom leaves each transplant to build expansive root base. And the reason: Shorter growing season.

  3. Thanks to all for your kind words and enthusiasm! I hope the article really did prove to be helpful and that you all had wonderful tomato crops!


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