Do It Yourself: Seed Starting

Now that the new year has arrived, I find myself looking forward to the spring months—even though many weeks and months of winter still remain ahead. Preparing for this year’s garden in advance doesn’t harm anyone. In fact, this is today’s topic. 

Perhaps you’re the sort of person who likes to grow your own garden plants from seed, or perhaps you prefer to pick them up from the greenhouse ready to plant in the soil. I enjoy both for different reasons—but if you’ve held off of growing your own plants from seed for a specific reason, you might pick up some pointers to try this year!

There are several key benefits to starting your own seeds indoors, such as: 

Variety: Oftentimes there are more options available in seed packets than are sold in greenhouses, including heirloom varieties and certain types of plants that aren’t available pre-grown at all. This is a great way to set up your garden exactly as you like, with lots of time to prepare.

Quantity: If even most of your seeds germinate, you may end up with more seedlings than you anticipated, and at a far more cost-effective price than purchasing plants individually from the nursery to plant in the spring. If you end up with too many plants, you could always offer the extras to family or friends.

Control: When you grow your own plants from seed, you can control the process from the very start. Soil, moisture, lighting, and other inputs are all at your own discretion, including the ability to grow organic. 

Quality: Plants grown from seedling in small batches can often be stronger and receive individual care, resulting in sturdier plants once they are able to move outdoors. You can cater to specific plants based on their needs, and start to harden the seedlings off once the weather begins to warm up.

Education: Watching the plant growth cycle from the very start can expand your knowledge of plants and gardening as a whole, helping you to produce stronger plants and cultivate more crops during the season.

Growing Season: I know I’m always wishing for spring by the tail end of winter, and growing your plants from seed gives you that gardening enthusiasm before the snow even melts. On top of that, there’s a special sort of joy in watching your seedlings first break through the soil. Especially in cold-weather climates with a short growing season, this can help to extend the enjoyment of gardening.

This guide will intend to cater specifically to growing in Saskatchewan, but most of this information can be modified to suit different climates and timelines.

So you’ve decided to start growing your garden from seed this year; there are a few things you need to know before you begin.

Timing

As a typical rule of thumb, start your seeds 6-10 weeks before the last frost. Here in Saskatchewan, that typically lands around the middle or end of May, making March the ideal time to plant seedlings like tomatoes, cabbage, most annual flowers, and more. Certain plants, however, require longer to grow, such as peppers or geraniums. Be sure to check the growing recommendations on each seed packet, and track backwards to allow enough time. 

Be cautious about planting your seedlings outside before they’re ready, as a late-season frost could wipe out your hard work. May long weekend is typically a good weekend to plant, though many people prefer to wait until June. 

In the weeks leading up to outdoor planting, monitor the daytime weather. Seedlings do better once planted if they’ve been hardened off—given time to adapt to adjustments outside like direct sunlight, wind, or variable temperatures. This can help strengthen the stalks, and prepare the seedlings for their time outside. But again, be mindful of overnight temperatures, and bring the hardening seedlings back inside. 

Substrate

When starting your garden plants from seed, be sure to select the right growing substrate. Although you may use potting soil for your nursery-grown plants, seeds require a sterile, soilless medium. Most greenhouses offer a seed starting mix, which provides the right combination of materials like peat, coconut coir, perlite, or compost to give your seeds the best start. This media ensures good draining and disease prevention.

Another great, simple option is using peat pods—often in a plastic tray with a built-in humidity dome—which expand with water and provide individual spots for each of your seeds. These typically include directions for optimizing growth, including the appropriate amount of humidity and sunlight.

Make sure to label your individual pods or pots with the seeds growing there; it’s easy enough to mix up different varieties which may have different requirements. Most packages will also provide guidance for growing season and planting distance, so save them for when you plant your seedlings outdoors.

Growing Conditions

Seedlings require a bright, warm, and humid environment to grow strong enough for transplanting in the elements outdoors. Upon first planting, keep trays covered with a plastic dome for high humidity and moisture. If you have an electric heat mat, place it beneath your seedlings for consistent heat and to encourage growth. Once they take off, the heat mat will no longer be necessary.

Once germination occurs and seedlings begin to sprout, ensure they get a high amount of sunlight (12-16 hours) per day. Leggy seedlings with thin, weak stalks are a sign that they aren’t receiving enough sunlight. Supplement with grow lights if necessary. 

Shift the plastic humidity dome only enough to allow for air circulation, but ensure it still covers enough to trap some humidity inside. 

During the first weeks or months of a plant’s existence, the roots are thin and fragile. They require consistent watering—enough to keep up with a high level of sunlight and humidity—but not so much that the seedlings are waterlogged, which can lead to root rot.

Once the seedlings grow tall enough, remove the humidity dome entirely, but pay attention to ensure they still receive enough heat and humidity. Adding a tabletop humidifier can increase humidity where it’s lacking, especially in the cold and dry winter months. 

Before moving outside to begin hardening off—and eventually to find their next home in the soil—many seedling stalks may remain thin. Use a fan to simulate the wind, or brush the seedlings with your fingertips to help strengthen and prepare them. 

When preparing to plant your seed starts, be sure to visit Floral Acres! We have all sorts of planting supplies, including seed packets, seed starting mixes and trays, indoor greenhouses, heat mats and grow lights, and more. Our new Plant Whisperer’s Corner offers anything you could need! 

Moving Outdoors

Once the risk of frost is (mostly) behind us, the anticipation of growing your own garden plants can finally lead to the planting. Ensure your plants have had a chance to harden off for 7-10 days, especially for tender plants like tomatoes or peppers. Gradually increase the length of time your seedlings spend outside in a sheltered spot—and if the weather is agreeable, they can remain outdoors overnight. 

When the time to plant comes, ensure the soil is warm enough. Transplanted seedlings will be happiest in soil that mimics their current conditions. This includes consistent watering, but with adjustments to allow for the increased heat and sunlight of outdoor conditions. Once the seedlings take to their new soil, they’ll strengthen quickly.

Cool weather crops, including greens such as kale, spinach, and lettuce, can be sown directly into the soil once it’s warm enough to be worked. For the rest, wait until your seedlings are ready to go out. 

Additional Pointers

Seedlings that are leggy and thin to the point they cannot support themselves may benefit from topping, especially plants like tomatoes, peppers, or certain herbs. Once the seedling has developed 4-6 nodes (sets of leaves), take a clean, sterilized clipper and remove growth above a certain point. This encourages the plant to fill out laterally, splitting into two main stalks, rather than one. Please note that this can be stressful for the plants, and may require a few days of recovery. Also, topping too early may hinder the seedling’s development. 

Be sure to rotate your seed starts, especially if they’re in a growing tray together. This will prevent them from leaning one way or another, and ensure they all get adequate sunlight. If utilizing a grow light above the seedlings, this may be unnecessary. 

If you plant more than one seed per grow pod, remove the smaller or weaker plant by the roots once they germinate and begin to grow. Otherwise the plants will compete for limited resources, and neither will grow strong enough to transplant outside. 

If you don’t have a heat mat to place beneath your seedlings, the top of your fridge may provide consistent heat to encourage seedling growth. Prioritize sunlight once they germinate and begin to grow, however.

Plastic bottles cut in half can act as a humidity dome if you are planting individual seed pots. These will act like a miniature, homemade greenhouse. 

Young seed starts, freshly germinated, require more sunlight than they do as they become more established. Once your seedlings become taller and stronger, you can reduce the amount of daily sunlight. 

Seeds from previous years may not germinate depending on how the packet was stored. When in doubt, purchase new seeds to ensure the highest level of viability. No one wants to go through the effort of planting seeds, only for a low percentage of them to germinate. 

Both in growing my own seeds and growing nursery plants outdoors in my own garden, I’m often surprised at what I find year over year. As with so many other lessons in life, I’ve learned more through experience than anything else. Take the time and care to grow your own seeds, and you’ll have a better idea of what works and what doesn’t for next year. 

Growing your own garden from seed can be rewarding—but it does require more work. If you’re curious, give it a shot! 

Until next time!