Julie, Not beets nor red potatoes. Look at these pictures https://www.google.com/search?q=pigweed+images&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb Pigweed is of the Amaranth family. There is a Red Rooted Amaranth that is quite the weed here in Ohio. There are also many Ornamental Amaranths. I planted an Elephant Trunk Ornamental Amaranth and for 4 years the seeds were sprouting everywhere in the garden. Here is another link: http://en.wikipedia.org/wiki/Amaranthus_palmeri Perhaps you should capitalize on them and harvest some seeds, (they are very very small, but nutricious)

I am wondering if it is beets or red potatoes. the stems are real red. it is really bushy now, and it looks similar to a potato plant. I planted potatoes, anyway nearby it. it could be red potato plant. but i am wondering, i put down some fertilizer i never tried, organic chicken turds, and wonder what they the chickens ate! maybe some kind of seeds! i have no clue what it is! i will find out anyway! my garden is growing so poorly this year, we have too cool weather too much, and i made the booboo of planting the seeds way way too deep in the ground so they’re taking a long time to appear! don’t know what’ll be!julie julbug

Perhaps Pigweed? Does the stem get redder closer to the ground?

Looks like Pokeweed. http://www.ecologicalgardening.net/2011/07/problematic-pokeweed.html