Seed-Starting 101: 13 Tips and Essentials

Seed-starting is an essential skill to have as a gardener, no matter your experience level. I’ve found it’s a practice you either love or hate, based on the amount of success you’ve had in the past. So, for those who dread seed-starting season and the problems that come with it, this list is for you.

Here, you’ll find 13 tips and essential steps to use when starting seeds, from helpful gadgets to care tips and more. No more seed-starting stress—you can simply enjoy the excitement of developing a tiny seed into a beautiful plant.

Sow at the Right Time

As much as gardeners wish we could control the seasons, the truth is that the seasons control us. Climate dictates what we can plant and when. While you can plant outside these windows, your plants are unlikely to grow and thrive without some serious garden modifications.

That’s why the first seed-starting tip is sowing at the right time. Follow the instructions on your seed packet and avoid planting too early or too late. Growing out of season risks young plants being killed off by frost or not having the chance to mature before the season is up.

There is a way to get a head start on the growing season for gardeners with late last frost dates. You can start seeds slightly earlier indoors thanks to the protection our homes provide. Sowing guidelines will indicate how many weeks before the last frost you should start sowing to ensure the correct timing.

Consider the Best Sowing Method for Your Seeds

Sowing in seed trays is the recommended method for beginners for ease and simplicity. But it’s not ideal for all plants.

Some species don’t transplant well, so direct sowing is a better option. If you’re looking to fill a large space and don’t mind where plants appear (like in a wildflower garden), direct sowing is also far simpler than transplanting hundreds of seedlings one by one.

Take a look at the recommended planting method on your seed packet to determine what’s best for that particular plant. If you’re working with a crop that doesn’t like root disturbance but you want to sow early indoors, choose biodegradable pots or soil blocks that can be moved straight into the soil after last frost without handling the roots.

Manage the Environment

One of the keys to seed-starting success is ensuring the environment is ideal for seed germination. Conditions like moisture, light, and temperature need to be optimal to give your seedlings the best start.

If you’re sowing indoors, grow lights and heating mats are great tools to provide the right conditions. Grow lights ensure young seedlings grow upright and strong, compared to the uneven light coming from a window. Heating mats warm the soil to boost germination and root growth, especially important for heat-loving crops like peppers or tomatoes.

If you’re sowing outdoors, you can’t really control things like light and temperature. Timing and location dictate that. But you can control soil conditions by amending with compost to boost soil health before planting. It’s also vital to remove any weeds before sowing that may compete with your new seedlings for resources.

Use Fresh Seeds

Seeds don’t stay viable forever. The age of the seed, along with external factors like storage conditions, impact seed viability and germination rates. For the highest chances of success, it’s important to use fresh seeds wherever possible.

That’s not to say you can’t plant out that packet of seeds you found at the back of your shed, or the seeds you collected from your garden a few years ago and stored indoors. Germination past the standard one-year expiration date is not impossible; it’s just far less likely.

If you’re happy to sow a few old seeds you don’t mind not germinating, go for it. If you’re relying on growing a certain number of plants for a specific harvest or to fill a measured space in your garden, stick with fresh seeds.

Choose Soil Mix Carefully

In nature, seeds are naturally spread around by wind, water, or animals and germinate where they end up. Considering this process, you may think that you can sow your seeds anywhere in any type of soil, and they will grow. Unfortunately, that’s not the case.

Plants produce hundreds or thousands of seeds in the hopes that a couple germinate successfully. When you’ve paid for a packet of seeds, these are not the odds you’re looking for. That’s why selecting the right soil mix is vital for maximum germination rates.

When sowing in trays, your seed starting mix should retain moisture to promote germination without becoming soggy and inhibiting airflow. The texture should be fine to provide limited resistance to new root growth. Chunky potting mixes can block root growth paths and impact germination.

Purchase a specialized seed-starting mix or make your own at home. A common mix is one part coconut coir, one part perlite for drainage, and one part fine compost. But you can adjust the recipe according to what you have on hand, as long as the resulting soil characteristics are the same.

Sow Multiple Seeds Per Cell

Choosing the perfect soil mix doesn’t guarantee 100% germination. Germination rates actually differ depending on what plant you’re growing.

These rates are carefully controlled by seed producers, but if you’ve collected seeds from your garden, storage and preparation can have an impact. While it’s tough to know the exact percentage, it’s highly unlikely that every single seed you sow will germinate. For example, if you’re growing seeds with an 80% germination rate, one in five seeds will not sprout.

To account for these germination rates, sow more than one seed per cell or hole. It’s generally best to plant two to three seeds, depending on the species you’re planting. This increases the chances you get one plant per cell, rather than having a few empty cells and wasted soil mix.

Sow in Succession

Once you’ve purchased your seeds and prepped to plant, it can be tempting to sow all your seeds at once. However, that means all the plants you grow will mature at the same rate. They will also flower or fruit at the same time, leaving you with masses of blooms or produce to harvest in one short window.

You don’t want a mountain of the same crop harvested all at once. This will lead to food waste (unless you have plenty of friends and family to share with). Instead, sow your seeds in batches a few weeks apart—a process known as succession planting.

Succession planting spreads out the growing season to ensure there is always something to harvest and that your beds are always filled with flowers. Sow in batches around two weeks apart, and make sure you keep space for new transplants in your garden beds.

Label Your Seeds

Labeling seeds is often an afterthought that many gardeners forget altogether. Unfortunately, it becomes a massive problem when you have trays full of seedlings popping up and no idea what each of them is.

Immediately after sowing, make sure you label each of your trays with weather-resistant plant markers. Marking prevents any confusion and ensures you transplant your seedlings into the right location for their needs later on. It also helps you keep track of the performance of certain seeds or varieties, helping you decide what to grow again the following season.

Keep Seeds Warm

When spring arrives, increasing soil temperatures is the signal to seeds that they can begin germinating. If you’re sowing your seeds early indoors, that signal is missing. Without controlling soil temperature, your seeds will struggle to germinate, even if all other conditions are perfect.

Luckily, there is an easy way to manage soil temperature—heating mats. These handy gadgets are placed underneath seed trays to gently warm the soil and provide the ideal conditions for germination. This is particularly important for heat-loving crops like eggplants that need soil temperatures around 75°F to germinate.

Use Grow Lights

Another gadget that’s incredibly helpful for sowing indoors is grow lights. While it is possible to sow indoors in front of a bright south-facing window, you’ll see far more success when using a strong grow light. Stems will be stronger and grow upwards rather than toward the window.

Place your grow lights directly above your seed tray to encourage seedlings to grow upright. A built-in timer will ensure the seedlings get the perfect amount of ‘sun’ for a strong start. Adjust the settings based on the needs of the plants you’re growing.

Don’t Forget to Water

There are many things that can kill your seedlings or stop them from germinating altogether. But one of the most common is lack of moisture.

Seeds need a consistent supply of moisture to germinate and develop roots. Dry soil halts the growing process, quickly killing young seedlings before they have the chance to develop. This is most vital in the first few days after planting, but also while green growth develops.

Check your seed trays daily to keep soil moisture consistent. To avoid disturbing fragile roots, I recommend watering from the bottom by placing your container on another tray. Fill it with water and empty the excess once the soil is completely moist.

It is also possible to water seeds too much. Excess moisture reduces airflow and increases the risk of rot. Keep the soil damp but never soggy, managing drainage in both the container and your chosen soil mix.

To trap moisture and heat around your tray, cover the seedlings with a germination dome. This will reduce your need to water as often, maintaining humidity around the plants.

Maintain Airflow

Overcrowding and lack of airflow provide the ideal conditions for diseases to settle in. If your seedlings often rot and die off before they get going, this could be the reason why.

Avoid placing your trays too close to each other or other potted plants. If you’re growing indoors or in a greenhouse, use a small fan to circulate stagnant air. This also replicates a gentle breeze outdoors, strengthening the stems of your plants.

Harden Off Before Transplanting

Once you’ve followed all these tips and grown strong, healthy seedlings, the last thing you want is for them to die off as soon as you plant them in the garden. When sowing in a protected area, seedlings need time to adjust to outdoor conditions before you get them in the ground.

This period of acclimatization is known as hardening off. Slowly introduce your seedlings to outdoor conditions by moving the tray outside for a few hours each day, increasing the exposure over time. Eventually, you should leave them outdoors in their trays for at least a full day or two before planting.

Hardening off reduces issues with transplant shock, allowing plants to focus on establishing in their new locations rather than adjusting to changes in environment. After the plants have settled in, you can care for them as you do all other plants in your garden.