I am not really sure how to take care of a mint plant. I would like to get an idea of how much water I need to put in the plant. Some websites say to make sure the plant is not drying by putting water daily and others say to not put too much. Also, my plant has a white thing like a web from a spider, but I am not sure. The plant is turning brown. I don't know if I also need to transfer my plant to something a little bigger. How can I fix all these problems (I bought this plant from Walmart)?
Yes, your mint has probably had a bit too much water. Also it has filled its pot and therefore exhausted all the resources there. It is time to move it to a new pot by taking a piece of a root from the existing plant and planting in new soil.
If you take your plant out of the pot and break open the root ball you will find many very thin roots and a few very thick roots that it sends out sideways. Cut off a piece of the thick root and bury it horizontally just under the surface of the new soil in the new pot. Keep it moist for a while until you see new shoots emerging into the light; these ready rooted pieces get established very quickly. Then keep it as you kept the original mother plant, but with about half the water you have been using.
In addition to Colin's answer, when you repot, the right type of soil will make all the difference.
For your plant, I'd replant into a 1 gallon or even a two gallon pot. It will sustain the plant for the next year or more.
For example, you can start with a mix of peat moss. potting mix, and perlite.
- The peat moss will have a lot of nutrients and is highly water absorbent, essential for mint.
- The potting mixes usually contain some amount of fertilization and prepare the plant for future transplanting into the ground or a bigger pot.
- The perlite will allow the soil to be well absorbent, which will mediate the over-watering issue.
You should also mulch the top with some well-decomposed pine bark or "Gro-mulch" soil. That way you won't need to water as frequently.
Lastly, once your plant is showing new growth and looks sturdy, you can add some sort of high nitrogen fertilizer like blood meal. Mint is a heavy feeder I believe.