I was told that I needed to tie a string around cabbage to form a head. There are some leaves but a head has not formed yet. Will this help or hurt the plant?
No, you do not need to tie up cabbage. They will form a head without any help.
I want to know when to plant cabbage, broccoli, cauliflower, beans, watermelon, and pumpkin.
Here is a link to South Carolina vegetable gardening.
http://www.clemson.edu/extension/hgic/plants/vegetables/gardening/hgic1256.html
Do you tie or fold leaves over cabbage and/or cauliflower?
Most people prefer to tie them. After tying them, check them regularly until ready for harvesting. Mature heads are a fullydeveloped, clear white and compact head about six inches. You can cut them with a large knife, leaving at least one set of leaves to protect the head.
Should I remove the leaves of the cabbage that's laying on the ground?
You can, especially if they are yellow. It will not hurt the plant to remove them and may also make it more difficult for some pests to get onto the plant.
Cabbage, broccoli, lettuce, and collard plants like cooler soil than I have now, but the literature suggests setting them out now for a fall crop.
Really, the trick is to keep their roots cool. Hot roots are what cause cool weather plants to bolt or grow poorly in hot weather.
A heavy mulch around them along with making sure they are well watered will help keep their roots cool until the weather cools down.
My son participated in a plant sale for FFA in school and I bought some cabbages (beginning of June). I admit I was a few weeks late in transplanting them, but I got it done. It is now the end of August. They are a foot tall and the green leaves are tall (not surrounding the stock but more straight up/out). I am wondering if they will ever get a head of cabbage on them or if it is the type that doesn't get a head.
It sounds like standard cabbage, but if you want to send a picture, I can confirm that. Cabbage needs cool weather to head properly. If they have not gone to flower by the time it cools down, they should start to form a head.
The plants look great. But there aren't any heads. What did I do wrong? This is the second time.
They need cool weather in order to form heads. You can help keep them "cool" by placing mulch around the base to regulate the soil temperature. This article will help: https://www.gardeningknowhow.com/edible/vegetables/cabbage/cabbage-head-formation.htm