Gardening typically helps me unwind and relax. Then it’s time to thin the seeds and I get all sad. It’s kind of like choosing which of my three kids I would save! But then I stop. Pause. And think.
They are just seeds. And our goal is likely the same ~ to grow strong, healthy and happy seedlings.
Seedlings that are grown indoors to be transplanted in the garden and seedlings that are sown directly in the ground outdoors.
Both require thinning.
Crowded seedlings suffer a plethora of problems if they aren’t thinned out properly. It’s a simple skill you’ll want to master.
So if you don’t know how to thin seedlings or why you’d even need to know, this is the post for you!
Let’s take a deep breath together because seed thinning isn’t for wimps.
What does it mean to “thin” plants?
Thinning the seeds means removing some of the tiny seedlings so the remaining plants have room to grow. Grab that tissue now. This is sad stuff.
So yes, this means you are removing some perfectly good seedlings and sacrificing them so that another plant can grow strong and healthy. Womp. Womp.
In most cases, you’ll have one seed per container, seed tray cell, pellet, or seedling pot. Thinning seedlings is a common method that’s used to ensure proper spacing of plants in your garden.
Seedling that are growing too close together will end up competing with each other similar to the way weeds compete with our flowers and plants!
And vegetable plants that get overcrowded don’t produce as much food in the long haul as the ones that have plenty of room to grow. Some seedlings won’t produce any food at all!
Left “unthinned” the crowded seedlings will still grow into mature plants, but their growth will be stunted. They will become weak and leggy.
Indoor seeds in particular will also suffer from lack of air circulation which causes mold in your growth trays.
Do I have to thin my seedlings? (said in a desperate voice)
But let’s face it. Our clumsy fingers tend to get mangled in the teeny tiny plants and ruin the whole pellet. We end up saving almost nothing, if even the one plant.
It’s risky and almost always is a waste of time as the transferred and damaged seedlings don’t end up amounting to much.
This is especially true when I look at my lobelia, viola and oregano seedlings. Those plants are so tiny that I know my fingers can’t handle the job of separating.
If I tried to pull them out of the soil, I’d end up dislodging all the delicate roots, even the ones I meant to stay put.
The job of carefully separating crowded seedlings is boring, time consuming and pointless as those plants almost always just die anyhow.
When you are trying to pull their tiny root system out of the soil, you end up yanking almost all the plants out.
You’re lucky if you are still able to save the one plant! What a shame if after futile attempts to “save” plants you end up having none at all.
You must take extra time when you plant the seeds in the first place ensuring your seeds are properly spaced apart. {No judgement here!}
You will also waste less seed which is important when you are paying extra for organic seed or specialty seed with a higher price tag.
The problem for me is that I’m never convinced my seeds will germinate! Even when the packet promises a 70-90 percent germination rate per seed! Such a doubter.
I end up cramming too many seeds in each pellet thinking the worst. And of course, most of the seeds do germinate and I’m back to square one again thinning them out.
So carefully follow the instructions on the seed packet. Even so, you still might have to thin them out.
I can’t tell you how many times I thought I only put one seed per container only to discover later that several germinated.
Working with small kids + clumsy fingers + teeny tiny seeds can do that!
When to thin seedlings indoors and out?
You want to give your plants a healthy start in life with lots of space, light and air circulation…none of which they will get if they are too crowded.
The longer you wait, the greater the chance you will stunt the growth of the remaining plants.
In Buffalo, NY we have a short growing season, every day counts in getting those plants to maturity.
If you do decide to wait, then thin out seedlings once they get a few sets of their true leaves, but not more than 3-4 sets.
How to choose which seedlings to thin out?
If they all look pretty much the same, as in healthy, then cut the smaller plants off at the base. (I understand….this is painful for me, too!)
Be mindful that the tallest seedlings aren’t always the healthiest. They are actually the ones more likely to grow weak and leggy when they don’t get enough light!
So no to the tall and leggy plants. Goodbye. It’s been real.
If your seedlings are all the same size, then random thinning out is the route to take. If you want to give them a few more days to see if there’s a clear winner in the group, that’s okay.
But it probably won’t be a big deal either way. Whichever plant you choose should survive and thrive as long as you thin away.
How much thinning do I need to do?
This will give them plenty of room to grow and make your life easier when it is time to transplant them.
Don’t panic if you don’t have the exact amount of space as recommended on the seed packet, after all, you’ll be transplanting them within a few weeks anyhow.
The exception is if you used some more “unusual” pots, like the plastic dome chicken containers I recommend.
I just use those good ole gardening instincts when considering how many plants to keep versus purge. Works like a charm! Well. Sometimes.
Seedlings that are sown directly in the garden rather than started indoors must be thinned to the spacing requirements on the seed packet. After all, this is their final destination.
Breakin’ it down – Seed thinning step-by-step!
2.) Use the right tool for the job – Pruners are too big so I used my kids smallish hair cutting scissors. I didn’t want to accidentally damage other seedlings in the process.
I washed the scissors with mild soap detergent to disinfect them. You could also dip the blades in rubbing alcohol or wipe them clean with a cotton ball soaked in rubbing alcohol.
3.) Snip seedlings at the base. Don’t worry about the roots. If you try to yank the seedlings out of the soil instead of snipping them at the base, you could damage the roots of the one plant you are trying to spare.
And if you are trying to save a few to transplant to other containers then you have to be super careful here.
This is true for carrots and other root crops. Sometimes when you get deformed carrots, it’s due to damage done to the seedling roots when the plants were young. They never got over it….should have tried therapy!
4.) Give the remaining seedlings a little boost of all-natural fertilizer. Chemical fertilizers are hazardous and can damage seedlings by burning tiny roots.
Compost tea bags are great or you could brew your own. Seedlings also love liquid kelp fertilizer or fish emulsion.
My cauliflower confession….
My clumsy fingers did their best to disentangle each seedling from the bunch and I replanted them in new containers with more space.
So far, it’s worked. Only a couple of casualties thus far, but most of the plants seem to be okay.
If the transplanted seedlings don’t make it, I’m not going to sweat it. But because these seedlings were a bit bigger and not as closely planted together, I’m confident that I was able to extract them without damaging any root systems.
So regardless, I’ll have my original ones to transplant to the garden (the ones in the round pot.) Some seedlings are bigger than others and their roots not as spread out.
I would have never attempted this with the microscopic, (or so it seems), lobelia or viola seeds. I’ll keep you posted if they pop back into action and end up thriving!
My pencil trick….
That’s probably why I find out later that more than one seed sneaks into a hole. Not cool. Then I have to thin the plants.
I discovered that I like using a pencil to plant seeds. It makes the perfect sized hole for either planting seeds or transplanting seedings/very small plants.
It’s also easier to control the depth of your seed better when you use a pencil. You know how it is. Some plants want to be planted 1/4 inch deep while others are a half inch.
A pencil helps you regulate the process. Works like a charm. Try it! You’ll like it.
Couldn’t I avoid seed thinning if I didn’t overseed in the first place?
So if you have a six cell starter tray for your cherry tomatoes and you plant just one seed per cell, you might only end up with four plants germinating instead of six.
In fact, what will you do if you only end up with two plants? Two plants aren’t enough for your garden.
But if you plant more than one seed per cell, you increase your chances of getting at least six plants.
Also, if you put more than one seed in those six cells, you also save both space and starting mix. And you only have so many grow lights.
And you will end up with the desired number of plants. No point in growing from seed just to be short plants forcing you to buy starter plants anyhow.
How many seeds per hole? In my 25 years of seed planting, 2-3 seeds per hole should do the trick.
For seeds more than a year old, increase that to 4-5 seeds as germination rates go down the older the seed. But they can still work!
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