Knowledge from Olle Garden Bed: Tomato Seeds Planting

You may want to know when to start planting tomato seeds indoors. Well, it's January now At least that's true for most of the southern United States. Regular planting of tomatoes is an important part of growing healthy tomatoes. Knowing how to do this correctly in your situation will make young plants healthier. The following content also has some reference value for raised garden beds.

It takes a lot of work to start sowing indoors. You need to evaluate the amount of space for the starting station and final destination of tomatoes. Frost dates are an important part of this process. The type of tomato you choose to plant also depends on when it starts.

Let's discuss when to start seedling and how to do it in consideration of time. The easier it is to grow tomatoes, so building the foundation for a successful tomato transplant will have a huge impact on your overall gardening practice.

When to start tomato seed

The general rule of thumb is to start spring vegetable seeds 8 to 3 weeks before the last frost. For tomatoes, where to start depends on the variety you want to grow and your region. Keep in mind that the mode in which you start seedlings (indoor, greenhouse, etc.) is related to when you can properly start transplanting. Here, we will discuss each of these factors and break them down into making it easier to grow your own tomatoes at the right time.

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US Department of Agriculture starts tomato seeds in cold resistant areas

Most tour guides say tomatoes start six to eight weeks before the last frost date. However, it depends on the region you live in and the associated USDA growth area. For simplicity, we created a list of areas and planting times. This is highly summarized, and the rest of this article will address the nuances involved in starting and caring for tomato seedlings. In the tropics, plants that like heat will not have a spring frost date to cope with, and people there may be able to start tomato seedlings outdoors at multiple times of the year. Those who have more climate in the Arctic need to sow indoors and in a space not affected by the cold.

The following is the USDA's list of hardy areas and when to start tomatoes. To determine when to start planting tomatoes in the southern hemisphere, refer to the map of the global cold tolerance zone:

Area 3a: sowing from early April to mid April, transplanting in late May and early June

Zone 3b and 4: sowing from mid March to early April, transplanting from mid May to early June

Area 5 and 6: Sowing from early March to mid March and transplanting from mid April to early June

Area 7: Seeding from mid February to early March, and transplanting from early April to early June

Area 8: Seeding will start from mid January to mid February, and transplanting will start from April to early July

Area 9: Seeding from mid January to mid February, transplantation from mid March to mid April, and transplantation again in early August

10a area: sowing from mid January to mid February, transplanting from mid March to mid April, and transplanting again in early September

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Area 10b: start sowing from the middle of January to the middle of February, transplant from the middle of March to the middle of April, and transplant again from early September to December

In areas with longer temperate seasons, there are more time options for transplantation. In the tropics, there are two very long growing seasons, one in summer and the other in autumn. In the 8b district where I live, tomato growers have two fruiting stages: one in spring and the other in early autumn. We spend time in the hot summer to let our tomato plants live and harvest for the second time. However, the average date of the last frost is not the only way to determine when to start. So let's address these factors below.

Tomato seed initiation method

The mode you choose to sow indoors will affect the success of seedling growth. Thankfully, winter gives most of us time to browse the seed catalog or view each seed package we have stored for spring. Those in more temperate or tropical regions may have to take a deliberate break to get the same planned time. This is because the soil temperature is warm enough to be used for a long time, and warm soil can usually grow healthier tomatoes.

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One thing is certain: planting tomatoes from their own transplants has a good root system and is directly related to planting plants that produce good fruits. Here are some ways to avoid weak seedlings, which will inhibit the beginning of spring.

Starting space

How much space you have is the key to deciding how to start. For example, the starting cost of tomato seeds is higher than the maintenance cost of growing lettuce or kale. You need a lot of direct sunlight. Most people need a growth lamp to supplement a small sunny window on the south side of the house from winter.

If you have enough space for outdoor greenhouses to protect seedlings from freezing temperature, you do not need to clear any space indoors. Let's go outdoors and indoors to start the various modes of seed.

How to start

Although windows are a good choice for starting tomato seeds, you need additional light and warmth from the light and heat pads, respectively. This applies to those who start sowing indoors, as well as those who start in greenhouses or planting tents. If required, a heating pad under the seed tray, flower pot, or starter block helps raise the soil temperature to 20 degrees Fahrenheit above the ambient air. Measure the temperature in the room and adjust the mat control so that the seeds have 60 to 70 degrees of heat from below for several hours. Tomatoes need warmth to germinate. In unheated outdoor greenhouses, a significant increase is provided.

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As we have already mentioned, the growth lamp is indispensable. Tomato seeds need light to germinate at the beginning. They need at least 8 hours of direct light to develop into sturdy seedlings. On the windowsill, use the growth lamp to supplement, especially where the obstacle blocks direct sunlight or the sun starts to have insufficient time lines. The windows facing south are very suitable for people in the northern hemisphere, while the windows facing north are most suitable for people in the southern hemisphere.

The growing tent provides you with a closed space where your plants can grow under the best conditions. Just like the initial setup with the growth lamp and heating pad, you can place the growth tent in any suitable place. The smaller growing tent is suitable for placing on the counter, usually with all the decorations needed to start all the seeds you want. You may get healthier plants from your tent because they can easily control humidity, temperature and light conditions. This gives you time to maneuver.

Greenhouse is another indoor choice for starting tomatoes. Here, the heat quality can be your heat source, and the greenhouse can also allow proper lighting. Supplement the growth lamp as needed. One of the awe inspiring aspects of the well stocked greenhouses and planting tents is that you will plant more successfully throughout the year. Once you put it down, the timing is unnecessary. For those who have a long winter, these options are the most feasible. Through climate control, you can have more choices about which tomato varieties you can grow.

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Seedling care

Let's introduce the steps of tomato seedling care with time. We will discuss sowing, taking care of sprouts and seedlings, and solving problems that may arise in this process.

Before planting

When planting tomato seeds, think about a few things a few weeks before the last frost. First of all, what kind of tomatoes do you want to grow? Do you plan to plant certain tomatoes, which are kept small and suitable for canning? Or do you want to plant indeterminate tomatoes that grow between 6 and 20 feet and need a trellis? Of course, you don't need to trellis seedlings, but plan for it.

Another consideration when it comes to tomato varieties is how to handle ripe fruit. Maybe you want to grow sauce tomatoes or bush tomatoes. Or maybe you want to plant cherry tomatoes. Perhaps the heirloom varieties are the most attractive to gardeners. Regardless of the type, follow the seed package to a certain extent to determine the time, spacing, and final destination of the plant. The seed pack usually contains more information about the specific tomato species you are planting and the basic needs.

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The planting and potted accessories you use have a huge impact on the transplant process. Plastic fermenters and trays can work, but they will decompose over time and may facilitate the transplant impact of small seedlings. Peat pots can be grown whole in the garden without disturbing the root ball. We strongly recommend our Epic6 cell initiation tray. Their function is the same as that of plastic starting cans, without the risk of electric shock, and they can last a lifetime. They will ensure a healthy transplant.

If you want to reuse the materials at home to start using, yogurt cup is a good choice. Egg boxes can also be used for germination. Egg boxes will be biodegradable like peat, but you need to quickly transplant seedlings into larger containers for root development. The yogurt cup should be disinfected before reuse, and its function is similar to that of plastic fermentation tank.

To start indoors, select a socket and add a soil mixture (or a soil free mixture). Gently flatten it. Your soil mixture can be a conventional potted soil or a potted mixture that contains modifiers as nutrients after germination. Do not submerge the seeds with fertilizer, because too much at an early stage will burn the plants and prevent germination. Sow within 6 to 8 weeks before the last frost. Place two or three seeds about 1/8 inch deep in the soil. Cover them on the soil line and press down gently. Then add enough water to make the soil moist. Keep wet throughout the germination process. Water regularly to dry the soil between irrigation.

Migration strategy

So you started eating tomatoes very early, far beyond the 6-8 week window. No problem, as long as there are appropriate climate controls and you are willing to magnify them before they go out. Don't plant them outside in cold weather! Instead, plant your seedlings in larger containers - gallon pots are effective - and the pot mix is modified with tomato food. They can also stay indoors. Take care of them like outdoor plants, and give them good growth conditions.

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Under normal circumstances, once ready, carefully transplant the seedlings into a raised bed or anything you use. Avoid too much interference with root ball, so as not to cause transplantation shock. Place peat containers in the garden as a whole. The same is true of soil blocks from the starting cells we mentioned above. Tomatoes like deep planting. Make sure the whole stem is covered at the base. Provide sufficient space between plants so that they do not overcrowd each other.


You may encounter some problems when dealing with seedlings. If you start early, you will have more time to solve the problems that often occur when you start planting plants by seeds. First of all, if you notice the thorny shape of the seedlings, you may water too much without enough light, or add too much light when there is not enough water. Because thorny seedlings will produce thorny plants, quickly adjust the light and water content so that you won't end up with a weak transplant.

This prevents germination if the air temperature in the starting area is too cold. It can also prevent the growth of sprouted seedlings, and may cause root rot and damping. Therefore, heat is an important part of tomato. The placement of light and heat pads and the ambient temperature are important.

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Another problem that may arise relates to diseased organisms. If you collect seeds from diseased plants (which are easy to happen when the disease is not easily observed) and start it, this may cause damping to fall off or fungus and bacteria to grow, thus damaging your plant. Most seeds from large distributors have quality control to prevent this, so please order from reputable sources. Start suspicious seeds from others to prevent the spread of disease.

common problem

Q: How long can I start my tomato seeds indoors?

A: The general rule is 6 to 8 weeks before the last spring frost. However, it depends on your situation.

Q: Can you start eating tomatoes indoors too early?

Answer: Yes! As long as you can potted into a gallon pot to provide good conditions for growth, there should be no problem.