Recommend you either cut one off or separate and transplant them both (my personal preference). Fairly easy to do, just handle them by the leaves and not the stems and transplant them deep to just below the cotyledons.

Good luck.

Dave

Thanks Dave. Do you think I will be able to separate the seedlings without harming their roots if they're growing that close together?

I guess there's only one way to find out. I'll probably give it a shot tomorrow.

Thanks again.

This illustrates the advantage of using individual plastic pots or trays filled with seed starting mix. You can plant only one seed per pot, or if using trays plant seeds spaced about an inch and a half apart. That way you don't waste half your seed. If a seed doesn't come up just recycle the seed starting mix and use it for planting something else. When you try to separate two seedlings growing close together in a peat pellet or tiny individual cell half the time you will end up injuring one or both. So to avoid that you have to play God and kill one or the other, wasting a perfectly good seedling. And forget the justification of culling the weakest one, usually both seedlings come up just as strong, or if one is bigger its just because it sprouted a day or two earlier. Commercial growers trying to sell containers or four or six plants might have to plant two seeds per cell to insure every cell has a plant in it as most people wouldn't buy a six pack with only four or five plants in it, but you as a private individual don't have that issue. Could be the seed companies push wasting seed too so they can sell more seed.

If they aren't too big you can seperate the roots carefully and repot. If I recall correctly, I have read that you really should repot because disturbing the roots help the plant adapt so that it can handle the transplant shock better when it goes into the garden where the light, soil and wind will be very differnt from its origianl home. (Of course, you should harden them off properly before transplanting....)

I have in the past taken a pot that had two plants in it that were pretty well grown and their roots were very tangled. I just took a knife and cut down between them and then transplanted each half deeper into another pot and they drooped a day or two, then kicked right in. Once they were in the garden a few weeks later, there was no way to tell which plants were the ones that had had their roots chopped off. Tomato plants are amazingly resilient.

Bets

Californian, Commercial growers do not plant one tomato seed per cell as you suggest. I know how seedlings are transplanted into cell packs as I have transplanted millions when I worked for a local grower. Seeds are first sprouted in special trays with trenches about 1 inch wide with maybe 200 or 300 seeds per trench, as long as a nursery flat.
At transplant time, about 2 inches of the trench is dug out and dropped onto the work table. Using a small tool the seedlings are separated somewhat and the plants are lifted by the cotyledons and planted into cells. The roots separate very easily. Don't wait until they have four sets of true leaves as the roots will be much tangled.
Occasionally one seedling won't make it to sale time. The missing plant is replaced with one from another pack of that variety.
When I seed my tomatoes for my home garden, I do it the same way except I start seeds in a 6 inch pot per variety and transplant into cells when true leaves appear. The seedlings are planted up to the cotyledons.

I should clarify, I did mean peat pellets, not peat pots. The expandable little things. So the seedlings are quite close together. Only about half the pellets have plants with true leaves already, ready to pot-up. So my plan is to take one of the strongest 'pairs' and see how challenging it is to separate the two. I'll separate and pot-up the ones I feel I can, then see how they handle it the next couple days. If it doesn't work, I'll 'play God' and cut down the weaker seedling per pot for the remaining pellets. And start over with the ones that didn't make it.

Thank you all for the responses. This is helpful.

Yeah the seedlings are much tougher than many give them credit for. ;)

As Shirley said, commercially a hundred seedlings are started in the space many home growers devote to 10 seeds and then easily transplanted to plug trays or whatever for additional growing. Those 4-6 cell packs you buy transplants in often aren't used until stage 3 transplanting.

We prick and deep transplant ours as soon as the cotyledons are well developed and the stems are firm, so do many others. It just takes a steady hand and bit of practice. ;)

Or you can, if you wish and are more comfortable, wait until first set of true leaves develop. Much longer and roots will start to get tangled but they can still be separated. As long as you don't break the stem and bury them deep 99% will survive just fine. Sure the tap root may break off a bit but that only leads to more fibrous root development.

Same goes for those peat pellet things. Once they have firmed up their stems, just wet the pellet and break it apart gently on a solid surface and pot up the seedlings.

I'm not saying you MUST do this, just that it is commonly done and is an available option if you wish to give it a try.

Not to mention better root development results IMO but then that is a whole other debate that we have had here many times before. ;)

Dave

In May I accidentally sprouted seed under odd circumstances. I wasn't sure it would survive, so I dropped three or four of the sprouts in each cell. It seems like all lived. Half are now in the ground. I've been culling those to one plant, but a nursery plant in my gardens and the article linked below has me second guessing this.

The nursery "plant" had three young plants in one 4" biodegradable pot. I sunk the hole thing in the ground without culling. The "plant" is as big and healthy (or bigger and healthier) as any of its neighbors, loaded up with fruit. I've been examining the growth from the soil up and seriously doubting if "one" plant in this spot would be as prolific.

Here's the article I found.

Here is a link that might be useful: Maximizing Production with Multiple Seeds Per Plug

Mojavebob,
I'm not sure what conclusion to draw from that article. As there's a difference between large scale commercial and home growing, would it be beneficial for the home grower to intentionally double up in each starter cell, assuming that there's no greenhouse issue (as the article mentioned), and if one has twice as many seeds as there are spots for transplants in the garden?
I would also assume that this does not apply to container gardening, what with the restricted root room and all. Maybe I'll experiment with that next spring.
Sorry for the battery of questions, I realize that you didn't write the piece, but you have much more experience than I.

Thanks,
Joyce

Hi Joyce,

I haven't drawn any conclusions either. I would be interested in exactly why I've always culled to one plant per cell. I just know I was told to do so long ago and always have. It appears they've grown out multiple plants per cell commercially for a long long time.

I have twelve plants/cells left from the accidental sprouting and a spot that will take nine of them. I have 4 with 3, 5 with 1 and 6 with two per cell. So, I'm going to plant three of each in that space as soon as I can and just observe the differences.