12 Essential Steps for Starting Seeds for a Lush Outdoor Garden This Spring

updated Mar 5, 2021
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a variety of herbs and lettuce plants outside with gardening tools
Credit: Alexander Raths/Shutterstock

While parts of the country might be already digging straight into their gardens for March planting, other areas are still buried beneath a blanket of snow for the first part of the month (technically, after all, it is still winter). But no matter the temperatures or the snowfall in your area, there is one outdoor gardening task you can do any time this month: starting seeds.

Starting seeds indoors in the late winter has been part of my life since I was a small child, so I can safely say that it’s a task that anyone can conquer with the right tools and directions. Remember to go easy on yourself — you will have successes and you will have failures, but that’s all part of the game. Try again if you fail. That’s how gardening works!

Here, 12 essentials to remember if you’re dipping your toes into seed starting for the first time.

1. Don’t get in over your head.

It’s easy to take a look at a seed catalog or at the rack of seeds in the store and go wild. I’ve certainly been there, tossing seed packet after packet into the basket, only to sort them later at home and realize that I don’t have to space or the patience to start all those seeds. 

Every seed will have different, individual germination requirements. If this is your first time starting seeds indoors, it will be helpful if you start with only two or three different varieties. It’s good to know that some seeds are much easier to start indoors than others. Also, remember that certain seeds (quite a few, actually) are meant to be sowed directly into the ground in the spring. Direct-sow seeds grow quickly and are a waste of time to start indoors, so skip those for now.

For beginners, try planting a few of the following seeds:

2. Consult your calendar.

When starting seeds, it’s imperative to get your timing right. After all, the whole point is that you’ll have seedlings that are ready to plant outdoors once the weather warms up. Seed companies make it easy for you. On the back of each seed packet you’ll find a timeline printed for your convenience. It will cover when to start indoors (usually x amount of weeks before the last frost) and sowing instructions (depth, days until germination, etc.). 

3. Find the right container.

A little research will tell you that seeds can be started in many different containers. It’s best to gauge your space limitations. Personally, I like using a plastic cell kit (I’m using this cheap one from Amazon) with a lid because they’re reusable, but there are many options out there including some that are self-watering. You can even start your seeds in a cardboard egg carton if you only have a thin windowsill to set them on.

4. Choose a soil that’s made for seed-starting.

Just like everything else in the gardening world, there are many different options to choose from when it comes to soil. You’ll want to start with a new, fresh mix of soil that hasn’t been contaminated by other plants. I personally like using a pre-mixed seed starting mix instead of typical potting soil. Seed starting mix is full of coco coir, peat, and perlite, which help manage moisture around the new baby roots and prevent root rot. It also contains small amounts of fertilizer to give your plants an extra boost once the seeds germinate. 

5. Prep your seeds.

Take another look at the back of your seed packets. It will tell you how deep in the soil to plant your seeds. Many times, tiny seeds can be sprinkled directly on top of the soil while others need to be buried. This is where an old pencil or pen will come in handy for hole-making. There are also seed-starting tools that have measurements printed on them. 

Sort your seeds accordingly. 

6. And don’t forget to prep your soil, too.

Once you’re ready to start the process, you’ll need to prepare your soil. You can’t fill the containers with dry soil. Use a bucket or a tub to dampen the soil mix. You want the mix to be damp, but not completely saturated. Use your hands or a hand trowel to mix. Don’t be afraid to get your hands dirty!

7. Fill your containers.

Pack soil into the cells of your container. Press the soil down firmly — you don’t want any gaps for air in the bottom of the cell.

8. Plant your seeds.

Follow the directions you noted on the seed packets in step 5. If your seeds need to be planted down in the soil, use the end of a pen or pencil to make a small hole. Drop your seed in and gently cover it with soil. 

Some folks like to plant multiple seeds per cell, just to up their chances for success. This is a great thing to do if you’re worried about your seeds germinating. If both happen to germinate, you can tease the seedlings apart, then replant one in another cell.

As you plant your seeds, label them by writing the names on seed stakes. You think you’ll remember what seeds are planted where, but you won’t. Believe me.

After you plant your seeds, water them by using a spray bottle. Using a watering can or other high-pressure device like a hose or sprayer can dislodge the seeds, and then you’ll be playing a guessing game for a few weeks as to where they are.

9. Cover your container.

It’s important to keep your seeds covered during the germination process. This helps keep the seeds warm and moist.

If you have a kit, put the lid on top of the tray. If you are DIYing, cover your pots or cells with plastic wrap. Once you see green shooting up from the soil, you can take the covering off. 

10. Give them lots of light.

In order to germinate your seeds, they will need a ton of light. If you’re like me and grow seeds in a window, try to pick a window with a lot of light, like a south-facing window. Make sure you rotate your containers so that all sides of the seedlings are getting equal amounts of light. 

If you grow under lights, the grow lights need to be 4 to 5 inches above your containers — yes, that close! Under these growing conditions, they’ll need 14 to 15 hours of light a day, and 9 hours of darkness.  

11. Keep seedlings warm and moist (but also ventilated).

You’ll need to keep the soil moist as your plants grow. To keep mold from growing, make sure that your plant trays are getting plenty of ventilation. Moving air also helps strengthen the stems of your seedlings. You can set up a small fan near your containers or turn on your ceiling fan.

It’s very important to remember that your seeds also need warmth. If your windowsill or grow space is too cold, you might want to invest in a grow mat (a heating pad for your seedlings) to put under your containers. 

12. Before planting outside, harden off your seedlings.

When the time comes to plant your seedlings outside (remember, check your last frost date to figure this out), you can’t just do it all at once. If you move your seedlings outdoors too quickly, they’ll stress and die. You need to harden them off.

To do so, place your seedling containers outdoors in a protected spot for a few hours a day. Over a week or so, move them further outdoors into the sun and elements, always bringing them indoors at night. After a week, they should be ready to plant in the ground so you can watch your garden flourish all spring and summer long.