Whenever I've planted Bright Lights I got all the colors, and I only planted 1 package. Yes the color of the stem as a seedling will be the color of the plant at maturity.

Which company did you buy your seed from? It sounds to me like you got a mixture of Rhubarb Chard and regular chard, not the Bright Lights at all, or else some of the package didn't germinate.

I bought a package of Burpee seeds from Lowe's. I don't have a big yard so I've only planted a few seeds, about 18 in the spring (which after thinning and disasters gave me about six plants, half red and half white). So far, I started 12 seeds and have gotten 18 seedlings, 15 red, 1 white, 1 yellow and 1 orange, all in different cells.

Side question, does each seed only sprout in one color? If I planted two seeds in one cell and there are three red seedlings and one yellow, does that mean one seed germinated three seedlings and the other germinated one?

You are doing better than anyone else I know, if you got 18 plants from 12 seeds. Are you sure a few didn't fall into the pot when you were planting.

I'm not saying it couldn't happen just that in all the years I've been gardening, I've only ever got 1 plant from 1 seed.

If you didn't plant the whole package that explains why you didn't get all the colors. If you were to take 5 seeds of each color and mix them up. What do you think your chances would be that you would get 2 seeds of each color---impossible. The seed is not that expensive--plant the whole darn thing and thin out what you don't want.

As to your last question. It's impossible to get 2 different plants from 1 seed. The seed is genetically programmed to produce one variety of plant and only 1 variety.

You are doing better than anyone else I know, if you got 18 plants from 12 seeds. Are you sure a few didn't fall into the pot when you were planting.

I'm not saying it couldn't happen just that in all the years I've been gardening, I've only ever got 1 plant from 1 seed.

Aren't swiss chard seeds like beet seeds, actually a "fruit" with several seeds within? IIRC, chard is in the beet family and usually one beet seed gives me 2-4 seedlings. I wasn't at all surprised to see the same thing happen with chard.

Well if you have any information that 1 seed-- either beet or chard or anything else--gives you more than 1 plant then pass it along. I have been gardening for 30+ years and I have never heard of such a thing.

If it were true when you plant beets you'd have a lot of little beets with no room to grow. That would defeat the purpose of the plant, so I can't see it happening. I know it has never happened in my garden.

I'm always willing to learn--prove it and I'll believe

Some quick Googling leads me to the University of Illinois Extension saying:

The beet 'seed' is actually a cluster of seeds in a dried fruit. Several seedlings may grow from each fruit.

Plus, I double-checked my three veggie books, they all say the same thing about beet seeds (and, oddly, don't say much about chard).

Yes beet seeds will sprout more than one sprout from each 'seed' Think of them as many seeds packaged in one bigger 'seed.'

Some seeds like from citrus and mango can produce many shoots from one seed because they have multiple embryos inside.

Maybe the seed strains offered by certain companies aren't very good. I grew "Bright Lights" from seed this spring and, out of a mass of seedlings, I got a tiny handful of yellow-stalked plants, a few deep reds and an awful lot of wishy-washy pinks. No oranges at all. I've grown them in the past and had all kinds of stem colours.