When you’re new to gardening, starting plants from seed might sound like an intimidating task. At least it did to me. Seed starting just looked like a lot of work that required the kind of gardening skill only master gardeners would possess.
But I moved out to my husband’s farm and was forced to face my seed starting fears head-on. And it turns out that seed starting is really not that difficult. You can do it, and I’ll show you how.
Starting your vegetable garden indoors a few weeks before your planting date is the best way to germinate seeds for a healthy garden later. Here are step by step directions to starting seeds indoors.
Step One: Gather seed starting supplies
1.Seed starting mix
It is of utmost importance that you use a fine grain seed starting mix, aka germinating mix, to start your seeds. Potting soil and garden soil are too dense and contain sticks and debris that you don’t want when you’re starting seeds.
Germinating mix is usually available at garden centers, but can be hard to find if it’s not early spring. Learn to make your own seed starting mix in my book, Seed Starting For Beginners.
2. Seed Starting Containers
We use multi-cell seed starting trays (like this) with clear dome lids which are great for starting 50-100 seeds at a time. If you’re not ready to do that many at one time, there are many kits to accommodate smaller quantities.
If you’re just doing a handful of seeds, try one of these 10 Ideas for Upcycled Seed Starting Pots.
For a home gardener, the best seed starting kit includes the plastic cells, a tray they sit in, and the dome which traps heat and moisture. Here is a good option that includes all of that plus a heat mat which I will talk later in this post.
Before you start planting, make sure you have a way to label your seed starting containers. All the little seedlings are going to look the same, and if you have any plans to save seed you need to know the name of the variety you planted.
You can use a popsicle stick, plastic fork, or even cut off a piece from some old mini blinds. Just choose something small and waterproof.
This is not the time for the cute labels. You’ll use something prettier when you plant it out.
Check out these great ideas for garden markers to use in your vegetable garden.
Unless you’re only planting one variety or one type of plant, you won’t remember what was planted where if you don’t label your seed starting tray.
Hopefully, soon, you’ll be saving your own seeds, but for any you don’t have, choose your favorite seed supplier.
Don’t worry too much about which seeds you choose. Yes, there are differences between heirlooms and hybrids, but both should be welcome in your garden.
As a home gardener, you can not buy GMO seeds from seed suppliers. They are only available for sale, usually in bulk, from the manufacturer of the seeds and you have to buy a license to use them.
So don’t worry that you will accidentally grow GMO produce if you don’t buy organic seeds.
Learn more about the difference between heirlooms, hybrids, and GMOs.
Want suggestions on what to grow?
One of the most common reasons for seeds to fail to germinate is not having your soil at the right temperature.
Your seeds need to be warm and cozy if you are going to coax the little baby plant out of them. Appropriate germination temperatures vary by type of plant, so check your seed packet for ideal germination temps.
We use these garden planning spreadsheets which tell you the date and the temp to start your seeds.
The best way to keep them at the right temp is to put them on a seed starting heat mat with a thermostat. This is not the same thing as a heating pad. Don’t use a heating pad.
You can purchase a heat mat with a thermostat on Amazon for around $20.
In a pinch, you can rest your seedling tray on top of your refrigerator. This should get you pretty close to the right temperature for germination for tomatoes and peppers. But, just in case, I would plant a few extra since you can’t regulate the temperature very well up there.
Step Two: get the seed starting mix into your trays
Pro tip: Water the germ mix before you fill the trays.
Damp germ mix is easier to work with, fills your containers more evenly, and prevents dry patches in the cell.
You’ve got the right amount of moisture when you squeeze the germ mix in your hand and it holds its shape but is not soggy.
To get the damp germ mix in the tray cells, spread the dirt loosely on top until all cells are filled. Don’t force the mix into the cells, you don’t want the soil tightly packed in the trays.
Here we have five trays ready to plant. In the image above, my husband is dibbling which just means poking holes in each cell for the seeds. He’s actually using an old nail head, but a pencil or pen is just the right size, too.
Let the kids use their fingers or just grab whatever is around you.
It is not necessary to dibble before starting seeds. You can also rest the seed on top and then push gently on it with your finger to set it in. However, if you are working outside on a windy day, we recommend you dibble then drop and not the other way around.
Step Three: label then plant seeds
I recommend labeling your tray before you start putting in seeds and working one variety at a time.
It is very important to go in that order. If you get distracted and forget which seeds you have started or which cells they’re in, you could be in a mess later. Many seeds are very, very tiny, and it is possible that you won’t be able to see if you’ve already dropped the seed in the cell.
Step Four: cover seeds
When all seeds are safely poked into their new homes, cover lightly with loose germ mix or vermiculite.
Vermiculite is a naturally occurring mineral that is mined and shredded to form the product we use in the garden. It is very light-weight and super absorbent. Seedlings easily push up and through vermiculite at germination.
Here’s a video we made that gives you the whole run down of seed starting.
When planting tomato seeds, we place one seed per cell. There are some reasons you would plant more than one per cell. If you aren’t sure of the viability of your seeds or can’t control their temperature and hydration definitely plant 2 or 3 per cell.
If you plant more than one per cell, and they all sprout, you may need to pick the strongest sprout and pluck the others.
Look at these trays of basil plants. See how many tiny plants there are per cell? With basil and many other herbs with tiny seeds, we sprinkle seed onto the germ mix and lightly cover with vermiculite.
As a side note, a lot of herbs do well when directly seeded into your garden, but make SURE the chance of frost has passed.
Take a look at this list of seeds that you can direct seed in your garden.
Step Five: water the seeds in
Once the seeds are safe in their new homes and cozy in their vermiculite blanket, water them well, but you don’t want them soggy. They will rot or mold if there is too much water.
A gentle spray to wet the top of the soil is all you need.
Step Six: taking care of the seedlings
All you have to do is keep them warm and watered. We recommend using a tray with a clear lid to trap moisture and retain heat.
Pro tip: place an oscillating fan near young seedlings. The gentle breeze helps them grow strong and sturdy stems and helps prevent leggy seedlings.
These trays are sitting on a 48″ heat mat and under two fluorescent grow lights.
Tomato and pepper seeds don’t need light to germinate. But the light provides some warmth, and they will need some light when the seed pops (pop=germinate=sprout) so you might as well go ahead and set them up.
You don’t need lights, you can use a window. However, seedlings grown in a window are prone to stretching which can create a flimsy, wimpy little stem.
Also, baby plants are very tender and fluctuations in temperature, as can happen in a window sill, can kill them. Investing in a heat mat and a light kit is really worth it. You’ll get a much higher germination rate and sturdier plants.
Sprouting tomato and pepper seeds
It will take 5-10 days for tomatoes to sprout, peppers can take up to 14 days, and most herbs will germinate after 5-7 days. Older seeds may take longer. Fresher seeds may be quicker.
Germination times and temps are included for many commonly grown food crops in the ultimate garden planning spreadsheets. They also calculate your germination rates so you can keep track of which plants are growing best for you.
If your seeds don’t come up, there are a few steps to figuring out what went wrong. Learn how to evaluate a low germination rate.
Seedlings are very tender, and they’ll need daily attention to keep them healthy.
Make sure you check on your seedlings every day. They are very susceptible to drying out, and they will die if you forget or ignore them. Make sure they are watered and warm and they’ll be fine.
I’m sure you have lots more questions like:
How long do the seedlings stay on the heat mat?
Remove the clear dome lid and turn the heat down or off once all the seeds have sprouted.
What if they outgrow the starter tray?
Transplant your young seedlings after they have their first set of ‘true’ leaves. That’s the second set of leaves that grow from your seedlings. Remove them gently and put them into their new homes. Choose a container that’s at least twice as big as your starter. We recommend transplanting into a 50:50 blend of germ mix and potting soil.
Learn how easy it is to transplant seedlings.
Do my seedlings need fertilizer?
Once your seeds have their first set of true leaves you can give them light fertilizer. Be careful to use something that is gentle and won’t over fertilize or burn them. We use a liquid organic fertilizer like this.
What is hardening off?
Hardening off is the process of setting your seedlings out in the sunlight for a few hours per day over several days. The purpose of hardening off is to acclimate your seedlings to direct sunlight.
If you’ve raised them indoors, they’ve been protected and direct sun can be harsh on their tender leaves. They’ll do better in your garden if you give them 4-7 days to harden off.
When should you plant them out?
This depends entirely on what you are planting. You should be able to find this information on your seed packet. It is also included in my garden planning spreadsheets.
How long until my seedlings produce food for me and my family?
It feels like forever, but really it takes about 3-4 months to get from seed to fruit. That is an excruciatingly long time, but oh the joy of your first tomato from the garden. It is a delight every single year.
A green tomato takes approximately 60-90 days to ripen on the plant. Seed to tomato definitely takes 3 to 4 months.
Herbs like basil, cilantro, and thyme can be harvested for leaves at around 6-8 weeks or whenever they have enough leaves to spare a few.
Peppers take about 90-120 days from seed to produce ripe fruit.
Once you get the hang of starting your plants from seed, you’ll find it hard to go back to buying plants. You don’t get anywhere near the variety of options by buying plants from the nursery.
It’s so much less expensive, and it’s really not hard if you set yourself up for success by following these steps.
Ask me anything!
Leave me your seed starting questions in the comments below!
I’d love to help you overcome any hurdles to starting your own seeds for your vegetable garden.