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Seed Starting 101 : A Complete Guide to Seed Starting

Seed starting is the process of growing plants from seeds. Once the seeds have grown into seedlings, they are transplanted to the garden. This technique enables gardeners to grow crops early in the season, allowing heat-loving plants to mature and bear fruits for a longer period of time. Seed starting is also perfect for growers faced with a short growing season; the process allows crops to mature before the weather changes.

Do note that not all crops are suitable for seed starting. There are crops that prefer to be planted directly into the ground because they cannot survive as transplants. In addition, different seeds have different growing habits so they must not be treated the same. Before setting off your seed-starting journey, you have to consider the types of seeds to sow, learn how to care for certain seeds, and what methods of growing to utilize.

Man planting seeds

Types of Seeds to Sow

When it comes to seeds, these are divided into two broad categories: warm and cool weather seeds.

Warm Weather Seeds

As the name implies, these seeds do well in a warm growing environment. These seeds prefer warmer soil and cannot tolerate frost. Some of the most popular types of warm weather seeds are summer vegetables and flowers: cucumbers, tomatoes, squash, beans, tomatillos, eggplant, peppers, basil, coleus, marigolds, zinnias, and nasturtiums.

Cold Weather Seeds

These seeds are quite hardy; they prefer the cooler climate and many can tolerate light frost. Many cold weather seeds are unable to germinate during the warm season so these are best sown just as the climate transitions to the cooler months. Some of the most popular types of cold weather seeds are: lettuce, kale, broccoli, beets, radishes, peas, carrots, spinach, kohlrabi, parsley, cilantro, and cabbage.

Seed Starting Methods

There are two types of seed starting method: indoor seed starting and direct sowing.

Growing plants

Indoor Seed Starting

This method involves sowing the seeds indoors using a growing medium. Indoor seed starting is a great choice for growers who would like to grow crops early in the season. Since the seeds are grown in a controlled environment, the germinating seeds are protected from harsh weather climate. That said, indoor seed starting can be time-consuming and it will take more space in your home. Generally, summer crops, slow-growing seeds, and hardy vegetables are best suited for indoor seed starting.

Direct Sowing

This method involves planting the seeds directly into the soil. This is an easy way of sowing seeds because the seeds do not require much monitoring. Just plant the seeds to the ground and that's it. No need to fuss with the lighting, transplanting, potting, etc. There is no need to think about transplanting shock once the seedlings sprout.

However, the seeds are exposed to the elements so they should be planted only when the season is right. In addition, the soil must be ready to encourage germination. Cold hardy seeds, fast-growing warm weather crops, as well as plants that do not survive transplantation well are best for direct sowing.

plants seedling in a small container

Containers and Growing Mediums for Seed Starting

Any type of container can be used for seed starting. But if you want to take this project up a notch, you can also buy a variety of seed starting containers and growing mediums. Here are just a few of the many to consider:

Cell Packs

Cell packs are compact, lightweight, and portable seed containers. These soil containers come in 4 to 6 cells but some cell packs come with more sections for growing seeds. Usually, cell packs can be joined together to fit into a plastic flat. Since cell packs are quite compact, they are perfect for a small-scale home environment.

Seedling Flats

Seedling flats are a high-density system that allows gardeners to grow more seedlings in a small container. Usually, the flat comes with a tray that holds excess water and prevents soil from draining away. Seedling flats are best used in nursery or greenhouse applications and not for a small-scale home environment.

Soil Blockers

Soil blockers are made by compressing seed starting soil in the form of blocks or cubes. Just plant the seed in the middle of a soil blocker and then transplant the soil blocker directly into the ground once the seedlings are ready. Soil blockers come in different sizes, some are perfect for small greenhouses, others are big enough for large-scale greenhouses. Because these growing mediums are made of dirt, you'll need a special mat to protect the soil from moisture loss.

Plants in a biodegradable pots

Biodegradable Pots

Biodegradable pots are typically made from cardboard pulp, dried coconut husks, paper, even cow manure (aptly called cow pots). These pots break down into the ground, which minimizes transplanting shock. The pots come in different sizes to accommodate a variety of growing environments. Biodegradable pots are more expensive than other growing mediums, which is something to keep in mind if you are seed starting for the first time. However, they are quite eco-friendly.

Seedling Pots

These are compact pots made from plastic. Since the pots come in different sizes, you can custom select the pot size and shape that suits your needs. Seedling pots are quite versatile, you can scale it up or down, depending on the size of the plant and the number of plants you are growing. You can pop the pots on a water mat to regulate the soil moisture.

Factors to Consider Before Sowing the Seeds

Ready to grow plants from seeds? Before you begin, there are certain factors that you should keep in mind. These are:

Plants in a biodegradable pots

The Quality of the Seeds

The quality of the seeds you will sow matters. You must choose high-quality seeds and varieties that are best suited for your region’s climate. High-quality seeds will germinate faster and at a much higher rate. These seeds will transform into strong seedlings and eventually provide the best yield. You can buy seeds from reputable suppliers. Our advice is to choose a supplier that conducts its own germination test.

Your Region’s Weather Condition

When choosing the best seeds to grow, choose those that are native to your region or seeds that are well adapted to the local weather condition. These seeds have a higher chance of survival because they have adjusted to the local climate. Again, look for sellers that conduct their own germination tests and field trials to determine what types of seeds to get.

Timing is Everything

The timing is a critical part of seed starting. If you sow the seeds too soon, you could end up with sickly, leggy seedlings that will not survive the frost. If you start too late, the plants might not have enough time to mature before the weather changes! Check the seed packs for general guidelines. Generally, seeds can be planted 6 to 8 weeks before the last frost date in the spring for indoor seed starting. For direct sowing, the seeds should be planted 3 to 4 weeks before the last frost date. As long as the ground is workable, you can start planting the seeds.

Man planting seeds in the garden

Step by Step Guide to Seed Starting

Now that you know the basics of seed starting, here is a step by step guide on growing plants from seeds:

Prepare Your Seed-Starting Tools

Start by choosing the right components for seed starting. That includes choosing the best containers to use, conditioning the soil for proper plant growth, and nurturing the seeds for faster germination. Always start with a clean seed-starting container, preferably about 2 to 3 inches deep with drainage holes.

We have already outlined some of the most popular seed-starting containers above, so choose for one that works for your needs and budget. Or, you can make your own seed-starting containers using yogurt cups, newspaper, fruit peels, or eggshells to save money and/or reduce your carbon footprint. If the budget allows, you can also buy a seed-starting kit although we recommend the more eco-friendly route. One thing to keep in mind when choosing the right containers for your seeds, you will transplant the seedlings into larger pots if you used small containers initially.

Preparing the Seed Starting Mix

Sow the seeds in sterile, bagged seed starting mix. The starting mix is typically loose and slightly moist. You can buy the seed starting mix or make your own using organic compost. Never use garden soil because plant seeds need nutrient-dense soil. If the potting mix is dry, moisten it with warm water before adding it into the seed-starting container.

Check the back of the seed packet for the recommended depth for sowing seeds. Generally, you want to cover the seeds with soil that’s equal to three times their thickness point. But again, different seeds have different growing needs. For instance, lettuce seeds and snapdragons prefer to rest on the soil surface as opposed to being completely buried in the soil for maximum exposure to light. After sowing the seeds, give the soil a light spritz of water.

Planting seeds in the garden

Nurturing the Seeds

At this point, you want to water the seeds carefully so they won’t drown. Always use room temperature water when hydrating the seedlings, these are quite temperature sensitive. The soil should be moist, never soggy or wet. Once the seeds have germinated and sprouts appear, water the seedlings carefully. This way, the moisture will not reach the leaves and cause rot or diseases to set in. Keep the soil moisture consistent. At some point, you might need to use plant covers or plastic wrap to retain the soil moisture.

Keep the soil temperature consistent as well. Seeds love warm soil but not damp air so keep the soil temperature at a constant 78° Fahrenheit and the air temperature below 70° Fahrenheit. Exposure to sunlight will affect the air and soil temperature. If the seedlings are not getting enough light, they will become leggy.

Seedlings require about 14 to 16 hours of direct sunlight. A sign that the seedlings are not getting enough light is when they start to bend towards the light source. If this happens, you have to relocate the seedlings to a spot that gets maximum sunlight. You can also use heat maps, artificial lights, and other tools to regulate heat and light. To keep the air movement steady, you can run a fan near the seedlings. This promotes proper air circulation, which inhibits the spread of diseases while also promoting stronger, more resilient stems.

You can apply fertilizer once the seedlings have developed their second set of true leaves. We recommend using a half-strength solution on a weekly basis. After the 4th week, you can go ahead and apply the full-strength fertilizer every other week until the seedlings are ready for transplanting.

To protect the growing seeds from excessive moisture and humidity, add a half an inch layer of light color sphagnum moss on top of the seed starting mix. The sphagnum moss will protect the seedlings from damping off and other types of fungal disease.

Man transplanting the seedlings

Transplanting the Seedlings

You can’t just transplant the seedlings once they grow big enough. You have to conduct a process called “hardening off” to acclimatize the seedlings to their new surroundings. If you skip this step, the seedlings may die because they could not adjust fast enough to their harsher environment.

To start hardening off seedlings, gradually expose them to the outdoors for a longer period of time. Place the plants in a sheltered or shady spot in the garden, perhaps, under a tree or near the bushes. Leave the seedlings exposed to the elements for 3 to 4 hours and then gradually increase the time they spend outdoors to 1 to 2 hours. Bring the plants indoors every night. Do this for a week or two and the seedlings should be ready for transplanting by day 10.

You can also use a cold frame to prep the seedlings for transplanting. Move the plants to a cold frame about 7 to 10 days before the transplanting date. Make sure the temperature does not drop below 50 degrees Fahrenheit or above 80 degrees Fahrenheit. Check the seedlings daily, making sure the soil remains moist. Within 7 to 10 days, the plants should be ready for transplanting.

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