Now that you've cared for your seedlings at weeks one and six, including getting them used to the outdoors (aka, "hardened off"), it's time to plant your babies. Of course these tips and ideas for how to plant seedlings will work for any plants, whether you've grown them yourself or bought them - and 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:
A Note About Planting Weather
Sometimes (actually, most of the time!) planting is all about the weather, no matter what your schedule or calendar says. For example,
- two weeks ago it was too cold and wet and I didn't want to be out
- then hot and sunny weather started last weekend and the plants wouldn't like to be transplanted when they'll just wilt in the sun (every few years we 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 my 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. (Tip: since we have such swings in temps during most springs here, I use covers for tomatoes so I can get them planted out earlier.)
How to Plant Seedlings
A. How to Prepare & Plant Seedlings in Individual Holes
1. My #1 tip for success: water the flat of seedlings really well, making sure that each sell is quite damp. Do this about 1-2 hours before planting - this is an easy way to help your little seedlings transplant well.
2. Prepared the garden bed - weed and spread a layer of compost.
3. Make holes at the spacing desired. Using lettuce as an example in a raised bed, I like to plant alternately: 4 plants in one row, 3 in the other so I can plant a little more closely, but traditional rows work as well. 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. Fertilize. Add about a 1/4 cup of organic fertilizer and mix it into the soil of each hole. You can buy an organic fertilizer like this one or make your own like the one I use from Steve Solomon's book, Growing Vegetables West of the Cascades.
5. Gently remove the seedling from the cell pot. Tip: 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, seen in the picture above. Whenever I've just pulled the seedlings out, I invariably loose some of the roots, OR break off the tender seedling, so always 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?)
6. If two seedlings are growing in one cell GENTLY pull the seedlings apart (this will be much easier if you've watered them well in Step 1). Grasp the section of root beneath each plant and start gently pulling apart to get as many roots separated as possible. Tip: Even if they don't separate evenly and you have one plant with all the root ball and one with just a bit, plant them both anyway - most of the time they will both grow!
7. Plant your seedlings in the prepared holes, bring the dirt around them and press down to firm it well, to make sure that all the roots are coming into contact with soil and there are no air pockets.
This picture above shows all the lettuce seedlings planted in an alternate planting method. Tip: The onion seedlings in the corners will line the raised beds - it's a good use of space, and it's pretty, too.
B. How to Prepare& Plant Seedlings in Rows
1. Dig a shallow trench as long as you need.
2. Add a line of organic fertilizer and mix it into the soil.
(Um, I know it looks like I didn't mix the fertilizer in the photo above, and well, that's because I hadn't yet. BUT I did later, I swear. I just got so into taking pictures that I forgot and had to do it later- learn from my mistake, ha!)
3. Place your seedlings at the proper spacing (according to your seed packet or square-foot garden guide). Since onion seedlings are grown all together, 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 should 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, in my book!
4. Then back-fill with the soil and firm everything in place around the seedlings.
When finished, the bed doesn't look like much does it? But these little guys will grow, grow, grow and soon you won't see any soil- trust me!
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.
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). This again uses an alternate pattern planting method like the lettuce, but these seedlings are spaced at a 3-2 plant spacing to allow for their eventual bigger sizes.
Bonus tip for brassicas:
Cover your broccoli, cauliflower, and cabbage starts with a floating row cover! After using them for years after losing whole crops to aphids and worms in the past I've found this really keeps them clean AND 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.
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: this post contains affiliate links and by clicking on them you help support AOC at no extra cost to you – thanks so much! Plus you can trust I'll only share what I love. (You can always read our entire disclosure page here.)