Starting seeds indoors is one of the best ways to get a head start on your growing season. Not only does it allow you to grow a wider variety of plants, but it also gives you complete control over the growing process. Whether you’re looking to save money, grow organic produce, or simply enjoy the satisfaction of starting from scratch, seed-starting is an essential skill for any gardener.
Why Grow From Seed?
I’ve been growing from seed ever since I started my first garden back in 2016. While I sometimes purchase starts (established seedlings that are ready for transplanting outdoors), I still choose to start most of my plants from seed each year.
There are several reasons why starting from seed is beneficial:
- Cost-Effective – A single pack of seeds can contain dozens (or even hundreds) of seeds and costs about the same as one plant from a greenhouse.
- Access to More Varieties – Many unique and heirloom varieties are only available as seeds.
- Full Control – You know exactly how your plants were grown, including whether they were organically raised.
- Better for Certain Plants – Some crops, like peas, beans, carrots, radishes, and beets, grow best when started from seed rather than transplanted.
- Create a Backyard Grocery Store – Growing from seed ensures you have a steady supply of fresh vegetables right outside your door.
- Healthier Plants – When you start your own plants from seed, you reduce the risk of introducing pests or diseases from nursery plants.
- Sustainable Gardening – Seed starting reduces reliance on commercial greenhouses, which often use synthetic fertilizers and pesticides.
Which Seeds Should You Start Indoors?
Some seeds are best started indoors, while others should be direct sown outdoors. Most seed packets will tell you if seeds should be started indoors or direct sown, and will also provide information like when to start, how deep to plant, how long seeds typically take to germinate, and when to transplant outdoors. You can learn more about how to read and understand seed packets here. In the meantime, here’s a quick guide to which seeds that benefit from indoor seed-starting:
Best Seeds to Start Indoors:
- Onions (seeds) – Need a long growing season.
- Peppers – Require warm soil and a long growing season.
- Tomatoes – Like peppers, tomatoes are warm-weather crops that benefit from an early start.
- Brassicas (broccoli, cabbage, kale, Brussels sprouts, cauliflower) – Develop stronger transplants when started indoors.
- Lettuce – Can be started indoors for an early harvest.
- Herbs (basil, thyme, oregano, parsley, etc.) – Germinate well in controlled conditions.
Best Seeds to Direct Sow:
- Peas and beans (legumes) – Prefer not to be transplanted.
- Root vegetables (carrots, beets, radishes, turnips, potatoes, onion sets) – Do best when sown directly into the soil.
- Corn – Prefers warm soil and often do better when directly sown.
Where to Buy Seeds
Most garden centers carry a wide variety of seeds, however you can also order online and get access to just about every seed imaginable!
Here on Vancouver Island in Canada, I get most of my seeds from West Coast Seeds. However I also love True Leaf Market in the U.S., and am planting a bunch of varieties from the “Homesteader Pack” from Survival Garden Seeds this year. So far the “White Grano” onion seedlings from that pack have had the best germination rate by far of all the onion seeds I’ve started this year!
(Use code HOUSEANDHOMESTEAD to get 10% off the Homesteader Collection, the Home Garden Collection, the Farmer Collection, or the Ultimate Medicinal Collection from Survival Garden Seeds)
When to Start Seeds Indoors
Each plant has an ideal starting time based on your last frost date. It’s important to know your frost dates as these dates mark the beginning and end of your growing season. The best time to start your seeds (both indoors and direct sowing them in the ground) will depend on your last frost date in the spring. If you’re not sure when your frost dates are, you can use one of these online calculators:
You should always check your seed packet for specific guidelines on when and how to start seeds, however, here are some general rules:
- Onion seeds – Start in January or February.
- Peppers & tomatoes – Start in late February or early March (I find peppers take longer, so I start them a little earlier).
- Brassicas – Start about six weeks before your last frost date.
- Herbs – Start 6-8 weeks before the last frost date.
- Squash and pumpkins – Start 3-4 weeks before planting out.
One of the things that will help you determine when to start seeds indoors is the “days to maturity,” or “days to harvest” of the crops you intend to grow. For warm season crops like tomatoes and peppers, you need to start them indoors because they wouldn’t have enough time to grow to maturity and produce a harvest if you had to wait for the weather to warm up enough outside in order to start them in the ground. The seed packet will often list the “days to maturity” or “days to harvest.” (If it doesn’t, you can simply Google the crop type and variety to find out).
Keep in mind that for crops that are typically started indoors (like tomatoes and peppers), the “days to harvest” actually begins when you transplant the seedlings into the ground.
Understanding Seed Germination Requirements
Seeds need three main things to germinate: moisture, warmth, and air. Once they grow into seedlings, they will also needs light, which we’ll touch on in a moment. But as far as simply getting your seeds to sprout is concerned, here’s how to ensure success:
- Moisture: Water the soil consistently, keeping it damp but not soaked.
- Warmth: Most seeds germinate at room temperature (68–86°F).
- Air: Ensure good airflow to prevent mold and damping-off disease.
- Pre-Sprouting: Large seeds like peas and beans can be soaked before planting to speed up germination. Others—like tomato and pepper seeds—can be placed in a damp paper towel inside a Ziplock bag until they sprout.
Some people like to use heating mats under their seed trays to increase germination rates. I’ve never used a heat mat and have always had success with seed-starting. Most seeds germinate when soil temperatures reach between 68ºF (20ºC) and 86ºF (30ºC). So long as you start your seeds in a warm place, room temperature should be fine.
You also don’t want your seeds or seedlings to get too hot! Avoid growing near drafty windows, or too close to heaters or wood stoves.
Choosing the Right Soil
I like to use a seed-starting mix as this is specially designed to maximize seed germination and growth. When transplanting seedlings to larger pots, I use potting soil to repot them.
The main difference between seed-starting mix and potting soil is that seed-starting mix is often a soil-less mix comprised of sphagnum peat moss, perlite, vermiculite, and coconut coir. This provides a good medium for germinating seeds as it doesn’t contain any larger, coarser materials that could prevent a tiny seedling from sprouting. It also retains moisture well, and it doesn’t contain any actual soil, which could harbour harmful pathogens and even weed seeds.
Avoid using soil directly from your garden for seed-starting, as garden soil can harbour harmful pathogens and weed seeds that can reduce your odds of successful germination and healthy seedlings.
If you must use garden soil, bake it at 180°F for 30 minutes to sterilize it.
Seed-Starting Containers
There are several options for seed-starting containers, with pros and cons to each. I used to use peat pots, but I had to purchase new ones every year since they are biodegradable. I also don’t have time to make them out of newspaper or toilet paper rolls or any number of creative things you can turn into seed-starting pots, so now I opt for reusable plastic cell trays and seedling pots.
- Seed trays/cell trays — Great for starting seeds, but most seedlings will need to be transplanted to larger pots)
- Peat pots — Biodegradable and easy to transplant, but you will need to buy new ones each year)
- Larger containers — Great for larger seedlings, but they take up a lot of space for seed-starting, especially if some of your seeds don’t germinate)
- Recycled plastic containers — Recycled containers like yogurt cups or red solo cups are cost effective, so long as you add drainage holes!)
- Soil blocks — Reduce plastic waste and allow for air pruning of roots. I’ve never used this method, so I can’t speak from experience on this one yet!
- DIY containers — You can make your own seed-starting pots out of everything from newspapers to toilet paper rolls to old egg cartons and even eggshells! This is fugal, but super time-consuming, and the seedlings will need to be transplanted and the containers discarded, so I don’t bother with this method.
How to Plant Seeds
Once you’re ready to plant your seeds, start by filling whatever containers you have chosen with seed-starting mix (or potting soil). I prefer to moisten my potting soil before planting, as it makes it easier to fill containers to the right level and helps keep seeds in place when watering after sowing. I use a spray bottle to wet the soil until it’s just damp.
General guidelines for how to plant seeds:
- Fill containers with seed-starting mix.
- Water the soil before planting seeds.
- Plant seeds at the correct depth (See below for further instructions)
- Lightly cover seeds with soil and mist with water.
- Label everything! – I use popsicle sticks and a Sharpie to label my seedlings with the crop type and variety.
Spacing Seeds
Typically you only want to plant one seed per container or cell in your cell tray, however I often plant a few extras, in case some don’t germinate (or I do it to save space and then I thin and transplant the seedlings when they get bigger). For example, I might plant three broccoli seeds in one pot, and then thin them down to one as they get bigger. By planting three seeds, I increase my chances that at least one seed will germinate, and then I can choose my healthiest seedling to keep.
Often I will transplant the thinned seedlings to their own pots, to increase my number of seedlings overall. I like to do this with lettuce: I scatter a few seeds in each pot or cell, then I carefully separate them and transplant them into their own pots get their first set of true leaves.
How Deep to Plant Seeds
As for planting depth, the seed packet will typically tell you how deep to plant seeds, however the general rule is that you should plant seeds twice as deep as they are big, so smaller seeds like tomato seeds, broccoli seeds, and lettuce seeds only need to be planted about 1/4 inch deep.
I often sprinkle a few lettuce and onion seeds on top of the seed-starting mix and cover with a light layer of soil. Then, as they grow larger, I separate them and pot them up into larger pots (I keep onion seeds more or less bunched together until they’re ready to go outside).
Larger seeds like peas, beans, zucchini, cucumbers, and winter squash should be planted 1/2-inch to 1-inch deep, depending on the size of the seed (cucumber seeds should be planted about 1/2 inch deep while large pea and bean seeds should be planted up to 1 inch deep). Keep in mind that pea and bean seeds are typically direct sown outdoors as they don’t like to be transplanted once they’ve established their roots.
Watering
It’s important to keep your soil moist when germinating seeds and growing seedlings. However, it’s just as important to ensure that the soil isn’t saturated, as excess water can cause seedlings tender roots to rot, which in turn causes the plant to wither and die. Damping off is a common seedling disease caused by soil that is too wet, so be careful not to overwater.
I use a spray bottle to water my seedlings. I usually take the lid off and pour the water into the pots or cell trays if the soil feels too dry. But if it’s still damp and just needs a mist, I just use the spray bottle to wet the top of the soil.
Providing Adequate Light
Seedlings need 12-16 hours of light per day. Natural light from a window is usually insufficient, so I recommend using fluorescent lights or LED grow lights placed 2-4 inches above the seedlings.
We use fluorescent shop lights as indoor grow lights. It’s important to provide seedlings with good light, and while you can start seedlings in a sunny windowsill, they will stretch toward the light and become “leggy” and spindly as they reach toward the window. You’re better off to use indoor grow lights.
Simple grow light setup:
- Attach fluorescent shop lights to a shelf.
- Use a timer to provide 14-hour light cycles.
- Adjust the light height as seedlings grow to maintain close proximity.
You can either use fluorescent lights like us, or you can opt for LED lights, which provide a broad spectrum of light perfect for growing seedlings. We’ve had great success using fluorescent lights in a variety of spectrums. We attach them to some simple metal shelves and hook them up to a timer that runs for 14 hours per day, which mimics a full spring daylight cycle. I also have a full blog post all about how we made our own DIY indoor grow lights (and how you can too!).
A sunny south-facing window is the next best option if you can’t use artificial light for growing indoors. Your seedlings will probably get leggy and spindly as they reach for the sun, but it’s better than nothing.
If you only have a few seedlings, this might be a fine option. However, if you have lots of seedlings, they’ll be vying for space in front of the window and the ones at the back will really have to reach, resulting in very leggy seedlings. If you must start seeds in a sunny window, be sure to rotate them regularly to give them all an equal chance to be as close as possible to the light.
Caring for Seedlings
The first leaves to appear on young seedlings is called their cotyledon. These are the embryonic leaves of the plant, and they usually look nothing like the leaves of the mature version of that plant. Once they grow a bit larger, their second set of leaves will appear. These are called their first “true leaves,” and will look like smaller versions of the leaves of the plant once it’s fully mature. If you’re using a seed-starting mix that does not have any built-in fertilizers (most potting soils and potting mixes do), you can begin fertilizing very sparingly once the seedling has at least two sets of true leaves. You can continue to fertilize ever two or three weeks after that. I just use an all-purpose organic fertilizer with a balanced ration of Nitrogen (N), Phosphorous (P), and Potassium (K).
You’ll also want to continue to water seedlings and keep the soil from drying out or getting overly saturated. And then, as your seedlings grow larger, you’ll need to thin them out, pot them up, and harden them off before they go outdoors. Hardening off” simply means preparing your plants for the outdoors, where they will be exposed to temperature fluctuations and the elements; this process helps prevent transplant shock.
It’s a good idea to use an oscillating fan on larger established seedlings to prepare them for the outdoors, or even just gently brush your hand over them to increase their resistance. Then, once it’s warm enough and they’re ready to go outdoors, you can start taking them outside for a few hours each day before planting them in the ground.
Once seeds have germinated:
- Thin them out – Remove weaker seedlings to avoid overcrowding.
- Keep soil evenly moist – Avoid letting it dry out, but don’t overwater.
- Provide airflow – Use a small fan to strengthen seedlings and prevent mold.
- Fertilize sparingly – Start with a diluted organic fertilizer once true leaves appear.
Hardening Off Seedlings
Before planting outside, harden off seedlings by gradually exposing them to outdoor conditions. Over 7-10 days:
- Start by placing seedlings outside for 1-2 hours in a shaded area.
- Increase outdoor time daily, slowly introducing direct sunlight and wind.
- After 7-10 days, they should be ready for transplanting into the ground.
Young seedlings are a lot like human babies—they need nurturing and protection from bacteria, disease, temperature extremes, and harsh elements like wind, rain, and intense sun. As they grow, they require controlled exposure to “the real world,” much like children and teenagers. And just like raising kids, if you care for them well at this stage, you’ll give them the best chance to grow strong, thrive, and produce a bountiful harvest!
Troubleshooting Common Seed-Starting Problems
There are a few common challenges you may encounter when starting seeds indoors. Here are some issues to watch for and how to fix them if they occur.
- Leggy seedlings – Long, spindly stems on seedlings resulting from inadequate light; adjust lights closer to the seedlings (they should always be around 2-3 inches above seedlings) or increase light exposure.
- Damping-off disease – Seeds either rot before they germinate or seedlings wilt and die shortly after germinating, usually due to overly wet soil; improve airflow and avoid overwatering.
- Slow germination – Soil may be too cold; use a heat mat.
- Yellowing leaves – Possible nutrient deficiency; use diluted organic fertilizer.
While these are the most common problems you might face when starting seeds indoors, other challenges may arise. While the internet is certainly helpful with troubleshooting most things, garden centers are a great source of information on seed-starting and troubleshooting. Befriend the folks at your local garden center and you’ll go far as a gardener!
At the end of the day, starting seeds indoors is a rewarding and cost-effective way to grow a thriving garden that’s well worth the effort up front. With the right setup, good soil, proper lighting, and careful watering, your seedlings will be strong and ready for the growing season ahead.
PS: If you need a little extra help planning your garden, Seedtime is a fantastic all-in-one garden planner and management app that I have personally used and loved. It can help you with timing, spacing, companion planting, and so much more. The best part is that the basic version is totally free (and actually quite robust!) Check out Seedtime here.
Wanna learn how to grow your own food?
Let’s face it: food costs are skyrocketing and only continuing to go up. Growing your own food is basically like printing your own money! Not to mention how much healthier and better-tasting it is. And you might be surprised by just how much food you can grow in a relatively small space.
But if you’re new to gardening, it can feel intimidating to get started. I know, because I was once a beginner who had NO CLUE what I was doing—and I made plenty of mistakes that cost me both time and money along the way.
Over the past 10+ years, I’ve learned how to feed my family from our backyard (well… front yard, actually!) on our modest quarter-acre property. Today, I grow hundreds of pounds of food for our family every year for practically free. Yes, there are some startup costs—but they pay big dividends for years to come. Investing in a garden is just about the smartest investment you can make nowadays!
If you’re ready to make that investment in your family’s food security, I’d love to invite you to join me inside my signature program, Seed-to-Soil.
Inside the course, I’ll teach you step-by-step exactly how to grow your own food from seed and create your very own organic grocery store right in your backyard. From choosing the right seeds and starting them successfully, to planting, harvesting, and even saving seeds for the following season, you’ll learn the simple, proven system I’ve used to grow abundant food year after year.
If you’re ready to stop relying entirely on the grocery store and start growing real food for your family, click here to enroll in Seed-to-Soil today.
I can’t wait to see you inside:)
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