How do I get rid of it and be able to plant vegies soon? Is round-up a good idea? If so, how long should I wait to replant with tomatoes, chard, etc? I live in Las Vegas, NV so anytime now is okay to plant.
Round-up will work and you can plant in about 1 week (2 weeks to be on the safe-safe side) after using it. That being said, you will likely see the mint come back regardless.
If you have not read it, this article may be helpful:
https://www.gardeningknowhow.com/edible/herbs/mint/invasive-mint-how-to-kill-mint-plants.htm
No matter what you do, you will need to lay down a heavy layer of mulch and/or a weed blocker like newspaper to help kill off the roots of the mint plants.
What is the best time of year to pot up a mint root from the parent plant?
Spring is the best time, but it being mint, you can really do it any time of year and it will do fine.
I am new to gardening and I have planted some mint, it is growing horizontally. I have read on some places that it is supposed to grow 8 inches tall. Should I attach it to a stake, or be patient and wait for it to root? I planted it 5 days ago. It has doubled in size, but not vertically!
Typically, mint does not require any staking, though it will not hurt the plant to do so...if it makes you feel more at ease. There are numerous types of mint plants, so it growing characteristic depends largely on the variety you are growing. This article will help you with growing mint in the garden: https://www.gardeningknowhow.com/edible/herbs/mint/how-to-grow-mint-plants-in-your-garden.htm
We have a large area (6 feet by 6 feet) of mint plants in our yard that need to be killed. The previous owners of our new house said the area of mint has been there for years and they tried to kill the plants too. I am willing to use anything.
Round-up or boiling water will kill it, but they will both also kill anything else they come in contact with. You can also try covering the area with a scrap piece of carpet for a few months. This article will also help:
https://www.gardeningknowhow.com/edible/herbs/mint/invasive-mint-how-to-kill-mint-plants.htm
I have mint (which I did not plant) that has taken over my flower garden. Yesterday I dug up a bucket full of roots. Now what should I do with them? I can't put them in the mulch pile or they will grow again. How do I kill them and eventually dispose of them? I know I did not get all the roots, so am sure I will be pulling out more buckets of them.
You can simply put them in the trash. If you want to avoid adding to your trash though, you can boil the roots for 2-3 minutes and then place them in the compost. The boiling water will kill them and they will not be able to grow.
I am crazy about mints and I have a growing collection. I am concerned about having too many in a small space. Will they all just morp into one big mint and lose their separate identities? Is there a minimum spacing to keep this from happening? I can only find general info on the web and even less in books. Am I worrying needlessly?
This article will help with growing these plants:
https://www.gardeningknowhow.com/edible/herbs/mint/how-to-grow-mint-plants-in-your-garden.htm
Recently I was given a somewhat sorry looking mint plant. I looked it up and placed it in a sunny window after hearing it loved the sun, but overnight the edges of the leaves started darkening and curling in, and the leaves kept wrinkling up almost as if they were scorched! So I moved it out of direct light, but still in a sunny room, yet the leaves continue to burn and die, and the stems are browning. It's like the whole plant is drying up, but the weather hasn't been that hot. I water it, there are no signs of insects, it's out of direct light, but it still isn't doing well. What am I doing wrong?
If it was dug up for you from the ground, it may be transplant shock. This article will help: https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm
If not, it may be root rot. This article will help with that:
https://www.gardeningknowhow.com/plant-problems/disease/treating-root-rot-gardening-tips-for-housplants.htm