How to plant seedlings that not not only live, but thrive all season. A step-by-step tutorial for planting seedlings and transplants in your garden to give them a good start and produce food (or flowers) for you throughout the season.
You can find tutorials on starting and caring for seeds in our Seed Starting Guide.
Some links in this article are affiliate links and if you click on them I will receive a small commission at no cost to you.
This tutorial and the tips I've included for how to plant seedlings in soil will work for any plants, whether they are vegetables or flowers, or whether you've grown them yourself or bought them. In fact most years it's a mixture of both in my garden.
Before we get to the nitty-gritty, though, I have one very important tip to share with you.
Think About The Weather When Transplanting
Sometimes (actually, most of the time) planting is all about the weather, no matter what your schedule or calendar says.
- Two weeks ago it was too cold and wet and I didn't want to be out, let alone the tender seedlings.
- Then hot and sunny weather started last weekend and the plants wouldn't have liked to be transplanted - they'd have more of a chance of wilting in the sun (every few years we do hit 80 degrees in April here in western Oregon).
Trust me on this- I have lost many tender lettuce and other spring seedlings by planting them on sunny days when it's fun to be outside!
Unless there is a way to shade them, it's best to put them out on overcast days or at least cooler sunny days.
A perfect day would be one that is a mixture of sun with clouds, with the highs around 65 degrees.
And warm-weather-loving transplants like tomatoes, peppers, or seeds like beans and cucumbers?
Don't even think about it until your overnight lows are consistently above 45 degrees (50 for peppers and corn), no matter what it does on an odd 80-degree day.
Your seedlings may not die if the temperature goes into the 30s, but they will be stunted and take a lot longer to rebound - and some may never.
Pro Tip: If you have spring temperature swings like we do, use covers for tomatoes to get them planted out earlier. They LOVE the extra warmth the first month.
What are the steps in transplanting seedlings?
The tutorial that follows shows you how to plant in both individual holes and rows, but the basic steps are the same:
- Water the seedlings.
- Prepare the soil.
- Add an organic fertilizer to the soil.
- Remove seedling from pot and place in soil.
- Tamp soil around seedling.
- Gently water.
How to Plant Seedlings (That Thrive!)
How to Prepare & Plant Seedlings in Individual Holes
1. My #1 tip for success:
Water the flat of seedlings really well.
Make sure that each sell is quite damp at least 1-2 hours before planting. This is an easy way to help your little seedlings transplant well.
2. Prepared the garden bed.
Weed if needed and spread a layer of compost or soil (I use the easy layering method for garden beds instead of tilling).
3. Make holes in the soil at the spacing desired.
Choose to make the holes in rows or plant alternately: 4 plants in one row, 3 in the other (or 3:2 for larger plants).
Alternate planting allows you to plant a little more closely and not have as much wasted space between rows (works best for raised beds where walking areas aren't needed).
Pro Tip: one of my favorite, quick ways to make small holes for seedlings is to use an English Dibber, which works for seeds, too, and is easy to drag through a raised bed to make a row for planting.
4. Add Fertilizer.
Pour about a 1/4 cup of organic fertilizer into each hole and mix it in with the soil.
5. Gently remove the seedling from the cell pot.
Holding the pot upside down, take your other hand and squeeze on the little cell bottom until the seedling pops out into the hand holding the pot.
Whenever I've just pulled the seedlings out, I invariably loose some of the roots, OR break off the tender seedling, so always try to turn the pots upside down and use this squeeze-out method (I'm just making that up- I don't think there's a "squeeze-out method," do you?).
How to Separate Seedlings Growing Together
If two seedlings are growing together a cell, remove them from the cell and pull the seedlings apart by grasping the section of root beneath each plant and GENTLY pulling apart to get as many roots separated as possible (this will be much easier if you've watered them well in step one).
Pro Tip: Even if they don't separate evenly and you have one plant with most of the root ball and one with just a bit, plant them both anyway - most of the time they will both grow!
6. Plant the seedlings in the prepared holes.
Place one seedling in each hole, bring the dirt around them, and press down gently to firm around the seedling to make sure all the roots are in contact with soil and there are no air pockets.
7. Water around the seedlings.
Use a light spray of water to water around the seedlings and help them settle into their new bed.
The raised bed above shows lettuce seedlings planted in an alternate planting method.
Spacing Tip: The onion seedlings in the corners will line the raised beds - it's a good use of space, and it's pretty, too.
How to Prepare & Plant Seedlings in Rows
1. Dig a shallow trench.
Make it as long as you need - in this case I make the trench go all around the edges of the raised bed for the onions.
2. Add organic fertilizer.
Lay it out at the bottom of the trench and mix it into the soil a bit.
3. Remove seedlings and place at the proper spacing.
Space according to the seed packet or square-foot garden guide.
If planting onion seedlings, which are often grown multiple plants to a cell or section, you'll need to gently pull each seedling apart by grasping at the base, close to the soil - again tip #1 - watering your trays - is important here and they will pull apart more easily than if dry.
Onion space-saving tip: lay them in the trench at closer spacing than recommended (about 2-3" apart) and then as they grow, pull every other onion for green onions, giving the remaining onions room to grow larger bulbs. This is a great use of all your space!
4. Back-fill with soil and water.
Firm everything in place around the seedlings and water in with a gentle spray.
When finished, the bed doesn't look like much at first. But these little guys will grow, grow, grow and soon you'll see a lot less soil- trust me!
Pro Tip: If you are using a soaker hose like I do (and I hope you are - or some type of system to water at the roots- for both easy care and healthy plants), make sure it's in place now, since it will be harder to set after the plants have grown.
Planting Seedlings FAQ
In general, you should wait until the seedlings are at least 2 to 3 inches tall and have their first set of true leaves (the leaves after the first set of seedling leaves).
Depending on the variety of plant, however, your seedlings will be different sizes. For example, tomatoes and peppers are typically bigger than lettuce seedlings since they need a bigger head start.
For most seedlings you will plant them at the same depth as they are growing in the pots.
There are a few vegetables that like to be planted deeper however, like tomatoes, peppers, cucumber, squash, broccoli, and eggplant.
Both! Water the seedlings in their pots well the day before transplanting and then water the plant in well after planting in soil. Just be careful to use a gentle spray to water the newly planted seedling.
More Examples of Newly Planted Seedlings
This small bed (at the end of a larger bed planted with peas) holds spinach in two rows and Chinese cabbage planted alternately.
Sort of. Sometimes I squeeze a few more seedlings if they are small to see if they'll make it - and if they do I transplant when they're stronger.
This bed holds broccoli, cauliflower and cabbage (also called cole crops or brassicas).
I always use the alternate pattern planting method for these crops, spacing the seedlings at a 3-2 spacing to allow for their eventual bigger sizes. This spacing really makes the best use of raised beds.
Bonus Tip for Brassicas:
Cover your broccoli, cauliflower, and cabbage starts with a floating row cover!
I've been using them for years after losing whole crops to aphids and worms in the past - it keeps them clean AND I've found they grow better under the slight insulation the cover provides. Win-win!
You can read more on why row covers are the way to go with your cole crops here - including the amazing cover-and-not-covered pictures.
This is a part of the Growing Vegetables 101 Series. See the other posts in this series here.
Note: Our classic vegetable gardening 101 series was published in the first year of the blog – 2009. It’s been republished with updated information and clearer formatting.Disclosure: affiliate links in this article will earn commission based on sales, but it doesn't change your price. Click here to read our full disclaimer and advertising disclosure.