The beginner’s guide to seed starting
Updated: May 12, 2023
One of my favorite parts of gardening is seed starting. It’s my chance to be a part of the growing process from the very beginning. And, just like a proud dad, I can show off my garden knowing that I’ve been with these plants since the beginning.
While seed starting isn’t as easy as just tossing some seeds in the dirt and waiting. It’s also not as tough as most blogs make it out to be. And you don’t need a ton of equipment or your own soil mix.
I’ve written this step-by-step guide for beginners — budding gardeners who want to know how to start seeds and which perennials are the easiest to grow.
Happy seed starting!
The fool-proof guide to starting seeds indoors
First things first. Gather all of the supplies you’re going to need.
Here’s my list:
Seed starting trays and plastic covers (any type of transparent plastic will work)
Seed-starting soil
Tongue depressors (popsicle sticks) to make labels
Small spray bottle for misting seedlings
Seeds
Step 1: Choose your seeds
This is the fun part! You get to pick what plants and flowers you’re going to grow. Choose anything from vegetables, summer flowers or perennials (flowering plants that come back year after year).
Some of the easiest flower seeds to start are:
Black-eyed Susan (Rudbeckia)
Lupine (Lupinus)
Catmint (Nepeta)
Allium (Allium)
Purple coneflower (Echinacea)
Snow-in-summer (Cerastium)
Yarrow (Achillea).
Note that some seeds have a very hard shell (Lupine for example). These seeds need to be soaked in water at least for 24 hours to make them germinate easier.
If you’re looking for easy pops of color in your garden, try these summer flowers:
Cosmos
Zinnia
Larkspur (Delphinium)
Targetes (Asteraceae).
Note that these are annuals and will only last 1 season.
Some plants like to be sown directly in the garden once the frost is over. Be sure to check if the seeds you want can be grown indoors first.
As far as timing goes, most cold-hardy perennial seeds need a long cold period before they germinate. Start your seeds already in December or January to enjoy plenty of seedlings to plant out by spring.
If it’s already spring, you’re not too late. Get going and you’ll still get to enjoy seedlings in no time.
Step 2: Fill your trays with soil
Fill your trays with soil and press it down. I use plastic meat trays that I washed and dried. This saves me a ton of money having to buy new seed trays every season.
(Add drainage holes in the bottom of each tray (if you use meat trays) so excess water can get out and not drown your seedlings.)
You want to press the soil down — but not too tightly. You want the soil to provide a stable base for the seedlings' roots as they grow.
As for soil, I use seed-starting soil from a local garden center. I do not spend time making my own… as you see on TV and every other blog online.
A seed starting mix has a finer texture than potting soil and contains ingredients like sand, clay, peat moss, vermiculite, coconut coir, and perlite. Normal potting soil is usually too much for delicate seedlings and can weigh them down as they germinate.
Step 3: Add the seeds at the correct depth
Use a spray bottle and dampen the soil before adding seeds.
Each seed packet will tell you how deep to plant the seeds. If you’re not sure, bury each seed to the depth of the fingernail on your little finger.
Cover them with soil. Depending on what kind of seed it is, add a little soil on top of the seed. Some seeds barely need to be covered.
I use a tongue depressor to write the name of the plant and add the label to the tray so I don’t mix up the seedlings later on.
Then, use the spray bottle again to gently dampen the soil.
Lastly, cover the tray with plastic to keep the heat and moisture in.
Step 4: Water and wait
Most perennial seeds germinate within 7-14 days.
I use a spray bottle to lightly mist the top of the soil when needed.
A good way to see if your trays need water is to check the plastic. If there’s condensation on it, you’re probably OK skipping a watering. If it’s dry, you need to water it.
You want the soil evenly moist, not soaked.
If you don’t have a misting bottle, go get one. It’ll keep you from using a regular watering can and possibly drowning your seeds.
Place your seed trays where they can get plenty of light and warmth. The ideal germination temperature is around 70-75 degrees Fahrenheit (around room temperature, 21-23 degrees Celsius). If your house or greenhouse is colder than that, it may take your seeds longer to germinate.
When your seeds start to grow, keep an eye on them often, and make sure you turn your trays every other day once the seedlings start to grow. This is because your seedlings will grow towards the light and look really funny and long if not turned.
You also want to remove the plastic once your seedlings are around 1-2 inches tall (25-50 mm). This is to keep them from rotting in the warm, moist environment beneath the plastic.
Step 5: Move your seedlings into larger pots or outdoors
When your seedlings are big enough to handle, you can transplant them to larger pots to continue growing. This process is known as pricking out your seedlings.
The reason you do this is to help your plant move from the 'seed' stage to the 'growing' stage. This gives your plant more room and nutrients to grow.
To do this, I use a tongue depressor to gently lift each seedling from the tray. I generally move 2-3 seedlings together to a new pot.
I use regular potting soil in each new pot and keep misting and watering until the plant is big enough to move outdoors. If I’m selling the plants, I move them once more to an even larger pot until a happy customer comes and takes it home.
Here’s a great idea for biodegradable pots that you can put directly in the ground.
That’s it! If you have any questions, drop me a line and ask!
Why grow perennial flowers and plants from seed?
Seed is way cheaper than buying fully grown plants. I can produce an entire garden of plants that would cost thousands of dollars otherwise. That makes seed starting a great idea for anyone just starting a garden or dealing with a large space or a tight budget.
With seeds, it’s also easier to experiment with plants and see what looks good and will actually grow in your garden or flower bed. If you bought perennials at retail, you’d be a lot less likely to get creative and try new plants.
It is also a fun project for kids. They’ll be excited to see their plant grow tall and have flowers on it which will give them a feeling of ownership.
You can also collect seeds from the perennials already growing in your garden and then you save even more money! Free seeds = free plants
Plus, I love to share. From seed swaps to Christmas gifts, collecting my own seeds has been fun for my whole family. OK, maybe not everyone… but they pitch in and help anyway.
My biggest piece of advice for seed starting is to just do it. It’s not something reserved for fancy pro gardeners… it’s for anyone with the patience and determination to make it work.
Seed starting troubleshooting
Only a few of your seeds germinated. What went wrong?
First, check the seed packet and make sure you followed the instructions for temperature and light. Then check the soil — if it got cold or too wet, the seeds may have rotted.
Dig up one of the little seeds and look at it. If it’s bloated and soft, the seed rotted and you need to start over.
If the soil was too dry, your seeds may have dried up before their roots could develop.
And maybe you just used old seeds and they’re no longer viable. (Here’s how to check if the seeds are too old.)
Don’t give up though! Try again and keep an eye on how much moisture you’re giving them.
Can seedlings recover from overwatering?
Maybe. It all depends on the plant and whether or not the roots have rotted.
Seedlings have little reserve energy and very few roots. This makes it harder for them to recover from overwatering compared to a fully grown plant.
If you’ve overwatered and you’re sure the roots haven’t rotted, pick the seedling out of the wet soil — keep as little soil around the roots as possible without damaging any healthy roots — and replant it in damp soil.
Your seedlings are long and spindly. Is there anything you can do?
Plants grow leggy and tall when they don’t receive enough light. They’re stretching to reach any light that they can. Poor little guys.
Try to keep your seedlings in a place where they receive adequate light. If that’s on a windowsill, make sure that you’re rotating the trays daily so they don’t lean to one side. And, if possible, go for a south-facing window with day-long sunshine to help them grow as strong as possible.
Can you fix a seedling that has broken at the top but is still connected to the root?
If the top of your seedling has broken off, make a clean cut on the stem a short distance below the break. This technique is called pinching and can be used to keep a leggy, thin plant from growing too tall or narrow.
When the seedling heals, new side shoots will grow from the nodes below the break.
But don't worry. Your plant will eventually grow to look a lot like it was supposed to. Although it will be shorter, fuller and wider.
Can wilted seedlings be revived?
If your seedlings just need water, water them and they’ll probably be fine.
If they wilted because they got too cold, maybe they’ll recover if kept warm. It depends on the plant species and just how cold it got.
They can’t be saved if they have a bacterial disease (called damping off). With damping off, the seedlings usually look like the stem has a black narrowed area and the top part of the seedling falls over. It happens a lot with seedlings grown indoors or under glass.
Throw these seedlings away and carefully wash any pots or containers you want to use again.
Moss is growing on top of the soil. Should you be concerned?
Moss is usually a sign that your soil is too wet.
Typically, moss on the surface of the soil will not harm your seeds or seedlings. Back off from watering too much for a few days and increase the air circulation around your trays.
If it bothers you, you can scrape off the moss. But I usually leave it and my seedlings turn out just fine.
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