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Growing a Garden: Starting from Seed
Growing plants from seed requires more steps than growing from a seedling. On top of that, every plant is different, and as such slight variations may apply. There is no one-size-fits-all solution to growing from seed, but there are ways to make sure you're doing everything you can. Below we look at some things to consider when starting a garden from seed.
Table of Contents
Seed Saving at Home
Perhaps you have been collecting seeds from grocery store vegetables or maybe last year's garden. Amazing! Seed saving is an ancient practice and a great way to develop local heirloom varieties. When planting seeds not produced by an official distributor, there are a few things to consider. First, seeds from grocery store vegetables and fruits may not provide what you're expecting. Remember, grocery food ships from around the world, so some of the varieties may not succeed in your climate. You may even find that some hybridized seeds won't produce a seedling.
Can I Plant Old Seeds?
What about those seeds tucked away in the desk drawer you forgot? Old seeds run the risk of failing to germinate. There are ways to store your seeds for more extended periods, but if this is your first season, your best bet may be to start with seeds purchased from a reputable source.
How To Choose What To Plant At Home
So, let's assume you want to grow a tomato plant this summer. You know that this heat-loving vegetable doesn't handle frost well and you plan on starting the seeds indoors. The problem is you live in a colder climate, but you know what to do. You go with a quick maturing tomato, like the Scotia variety, which develop in 60-days and place an order for your seeds. But what's next?
Container and Soil
You can start your seeds in purchased planting trays or containers you find around the house. These containers can be old margarine tubs, yogurt cups, or plastic storage containers and are great things to reuse as a means to reduce your waste output. Whatever you plant in has enough room for at least 2-3" of root growth. Also, check and make sure there are drainage holes at the bottom, even if you have to poke them yourself!
If you're reusing an old container, be sure first to clean it with soapy water. This initial cleaning helps wash away potentially harmful microorganisms that could hurt the susceptible seedlings.
You also need to consider what plants you will be producing in these pots. Lettuce, cucumbers, melons, and sunflowers have sensitive roots and require special care in transplanting. Speaking from experience, growing in trays for these types of plants is not impossible. As the plants mature, you may need to observe them to ensure they don't become rootbound.
What Is the Best Soil Mix to Start Seedlings?
To begin, you're going to want fresh soil to start your seeds. A sterile soil mix ensures that there are no soil-borne diseases to attack your tender seedlings. For this, you have a few options. One is to buy your soil in bags from your local garden supply.
How To Sterilize Soil For Seeds and Plants
For the do-it-yourselfers who want to try to do it at home, there are various soil sterilization techniques you can try. The sterilization methods below will ensure your soil is free from pests, diseases, and weed seeds.
How To Sterilize Soil With a Pressure Cooker
Steaming your soil is one of the best and most popular ways to sterilize potting soil and can be done with a pressure cooker. Pour 2 cups of water into the bottom of the pressure cooker. Then place a shallow pan into the pressure cooker with no more than 4 inches of soil. Cover the pan with tin foil and close the lid with the steam valve open. This allows the steam to escape. Depending on your model, cook at 10 pounds of pressure or on the custom cooking setting for 15 to 30 minutes.
How To Sterilize Soil With an Oven
To sterilize soil in an oven, place the soil onto a baking sheet or pan no more than 4 inches deep and cover with tinfoil. Then bake for 30 minutes at 200 °F (93 °C). After 30 minutes, remove the pan from the oven and let sit until cool with the aluminum foil on. Do not bake at temperatures higher than 200 °F as it could produce toxins.
How To Sterilize Soil With a Microwave
Sterilizing soil in the microwave is an easy and quick process, but may take longer depending on the amount of soil you need to sterilize. Using a microwave-safe container with vents, place moist soil in the container and place it in the microwave for 90 seconds. Remove the soil from the microwave and let cool. You can repeat this process for the remaining soil you wish to sterilize.
How to Make Soilless Growing Mix At Home
If you're looking to use a soilless growing mix, you can purchase from your local garden supply or make it yourself. To do so, combine two gallons of peat moss with two gallons of perlite or vermiculite and mix thoroughly. After the plant's "true" leaves begin to emerge, you can start feeding them a diluted amount of liquid-soluble fertilizer every week or so. Some fertilizer options to consider are compost teas, worm teas from your vermicompost, or store-bought liquid-fertilizer.
Please note that the peat moss mentioned above is a non-renewable resource. As an alternative, consider using coir, the outer husk of the coconut. It has become a popular renewable alternative.
Once you have your growing medium ready, be sure that it is moist and not heavily saturated when getting ready to start your seeds.
Prepare For Your Crop
As you are waiting for your seeds' arrival, you're on the hunt for some containers to grow your Scotia tomatoes. You find several old food-grade plastic containers and poke holes in the bottom for drainage. You choose to fill them with a soilless medium and make sure there is enough room in the vessel for root growth.
Sowing Your Seeds
Now that you have prepared your containers with your growing medium, it's the perfect time to sow the seeds. The packet that you received your plants will often have recommendations for how deep to sow. A standard measurement in planting is a depth of two to four times the diameter of the seed. But as with everything, this is not always true. Some seeds prefer to grow on top of the medium and not buried. Confirm individual seed planting depths before sowing.
Ideally, when starting from seed, there can be between one and three seeds per cell (if starting in a tray) or small container. Multiple seeds act as a redundancy if one fails. This planting method is standard and often determined by germination rate or the percentage of successfully germinated seeds under proper growing conditions. If multiple seeds sprout in a cell, as the plants mature, you can clip the weaker of the seedlings and leave the heartiest. After sowing in the seeds, add a thin layer of vermiculite atop the medium. This layer acts as a secure barrier for the tender seedlings to push through.
Estimate How Many Seeds to Plant
Examining your seeds, you note that you received 350 in your tomato packet with a germination rate of 90 percent. This number means that of your seeds, 35 are anticipated not to produce. But that is still a lot of seeds, even if you wanted to grow a dozen plants. Using the end of a pencil, you poke a hole approximately four times the diameter of the seed and sow two. Sprinkling vermiculite over the top of the seeds, you are content with your work. In the end, you decide to start twenty because it's your first time and you want to have backups. At least if they all start, you can give away extras to friends and family to grow in their yards!
Lighting and Temperature
Ensuring your plants have the right amount of light and a regulated temperature is essential for proper germination. To begin, let's examine light options for your seeds.
Are you planning on sprouting your seeds with natural sunlight or with an indoor light? It is possible to use sunlight and supplement your home lighting. Still, there are things to consider, like how some seeds prefer darkness to germinate. If some of your plants need shade, consider adding a cover to the container in place of lighting.
Growing in Natural Light
Were you planning on using natural light for at least part of your germination? Make sure you have a south-facing window exposing them to indirect sunlight. Direct sunlight may be too much in the early stages of growth.
Why a south-facing window? In the northern hemisphere, this is the side that will receive the most sunlight and, as such, is the favorite spot for most plants. Aim to provide them a cycle of approximately 15-hours of light and 9-hours of darkness, but every plant is different. Schedule your supplemental lights to come on a few hours before sunrise and turn off a few hours after sunset.
Also, as your seeds germinate and begin to sprout their first leaves, be sure to turn the tray often. Plants like to reach towards the light (i.e., sun, lamp, etc.), and by rotating the container daily, the stem develops evenly. The last thing you want is vegetables with stems so weak they struggle to hold the weight of their produce.
Growing Under Fluorescent Lights
When growing under fluorescent lights, aim to keep the bulb a few inches above the tops of the seeds and seedlings. As the plant grows, it will reach up towards the light above it. If it is too far away, the plant will devote more time reaching for the lightbulb than developing a sturdy base. The resulting leggy plant will still produce, though weakly.
Please note that keeping plants too close to high power lights (i.e., High-Pressure Sodium or Metal Halide) can also be detrimental. The heat produced by these lamps may be too much for the tender seeds. The goal should be to keep your seeds warm but not too hot. Aim for a daytime temperature between 65-75F (18-24C). Don't let the night time temperatures fall below 55F (13C). An excellent way to maintain these temperatures is to place a heating pad under the tray.
Tanner Sagouspe
Tanner Sagouspe has a Masters in Environmental Management and is a Permaculture Designer who promotes tackling the climate crisis at home.



