Yes, you must. If roots are tangled just take some little scissors and snip them off at ground level.
This is nature's way. But instead of forcing them to spend their lives in a futile struggle against each other for resources, you settle it right off with thinning. In a natural setting, a much smaller percentage of seeds survive than in your garden. Take solace in that.

Plant fewer seeds farther apart, the distance you want the adult plants to be, and replant later the ones that don't come up, and you will not have to thin.

If too many germinate too close together and you don't thin, you may not get a full size plant.

Hate thinning. Just hate it.

Welcome to the basics of horticulture for ~9000 years. All humans who plant food either get over it or plant fewer seeds.

Dan

If you don't like transplanting then you need to plant seeds further apart. Get yourself a mini seeder. You dial it to the correct size seed, put your seed in the small compartment and shake it in your row. You may have to thin some, but not much.

We plant this way and most things are planted far enough apart that I can thin the carrots when they are about 2 inches long and have a feast of baby carrots.

The reason you must thin is to give the ones you leave a chance to grow and get big. They won't do that if their roots are a tangled mess and they are competeing for room on top of the ground.

Dan, that made me laugh. I figured as much.

Going out now with my scissors. Deep breath.

With my summer gardening this just doesn't happen as much, I'm usually just dealing with one plant per space on my toms and peppers.

Thinning is one of the three ways of achieving proper spacing.

As mentioned, another way is to sow at proper spacing in the first place. But this usually results in gaps and uneven spacing due to sporadic germination.

The third way is to grow starts and set them out at proper spacing. I've been using this more and more. It gives uniform spacing and it uses seed economically.

Jim

Posted by oilpainter. . .
The reason you must thin is to give the ones you leave a chance to grow and get big. They won't do that if their roots are a tangled mess and they are competeing for room on top of the ground.

That seems to me to be the crux of it.

Think of it as doing a favor for the plants that remain. Instead of all the plants struggling, you are giving some of them a chance to thrive.

Adequate spacing is right up there with proper cultivation, fertilization and watering. It may be of even greater critical importance. Fortunately, many plants can be transplanted and often, there's room elsewhere for them. A mixed bed or row may be necessary, somewhere in the garden.

Steve

Definitely thin the root crops. Chinese cabbage is fairly tolerant of overcrowding but it will be small and elongated. Also, stressed plants like that won't have tender, juicy stalks.
You could always do like us and get a pet rabbit to eat the thinnings. That way you can dilute the guilt.

Y'know... thinned cabbage & turnip leaves are delicious

Lucky rabbits!

I do starts and I plant ONE seed in each cup. I rarely fail to get a plant from that one seed. I will start a couple of extra plants, just in case.

It's not like seed is cheap that I can afford to waste it growing plants that I know I will destroy. Why plant 20 tomato seeds to get 5 plants when I can get 5 plants by planting 5 seeds?

The leftover seeds store just fine to be used the next year.

I hate thinning too, (but I do it:). I have a broom handle with 4", 6", and 12" spacings marked on it in different colors. I lay the handle across my raised beds and then sow a tiny pinch (2-4 seeds) at the plant's recommended space designations. That way, I will always get at least one plant up at each spot, and only have 2-3 to thin out. It saves seed and the time it takes to prepare and tend to pots too.

I never thin. not necessary.

Do not thin. False advice.

Is thinning always necessary?

Of course NOT. What a silly question.

It's not like seed is cheap that I can afford to waste it growing plants that I know I will destroy. Why plant 20 tomato seeds to get 5 plants when I can get 5 plants by planting 5 seeds?

I agree with this!

Dittoes to oreogonwoodsmoke.

Jim

I had a friend who always complained that she couldn't grow carrots. She watched me thinning and said she couldn't bring herself to "kill" plants. So she never got carrots.

I kill wild carrots every chance I get, but it's like killing that hockey mask character in that horror movie, it keeps coming back to life.

Any tips?

How much garden are you doing? A small space or a 1/2 acre? I don't thin, unless they get thinned when I weed. I do what I call selective harvesting. I harvest out the bigger roots and crops first, then it allows the others to grow. Yes it does take a little longer to harvest, but when you are just one person on 1/2 acre, thinning would take longer than selective harvesting! Harvesting pays, thinning takes time.

ONE EXCEPTION: Beets. I do try to thin my beets. Not very good at it, but I try. They don't do well with competition. Carrots, I don't bother. I have over 500 square feet of carrots for this fall. Didn't thin a one and I have large wonderful carrots. If some are larger, smaller who cares!

Jay