Step 3: Make Candy!
Tie a long piece of cotton* string to a spoon, fork, skewer, etc. Then, measure the height of your jar and trim the string to this length. You may need to weigh your string down to keep it straight. For this, you can use anything that sinks in water - but avoid lead.
Place your jar in a place that it won't be disturbed for about a week.
After about a week, pull out your candy! If you don't see any growth within the first few days -- drain the sugar water into a pot, heat it and add more sugar. Also check that your string isn't super slippery.
If ants are a problem, place your jar on a plate of water - then add a few drops of detergent. This makes an ant moat.
Here at instructables HQ -- ants are a problem when it comes to leaving food on the counter.
*Do not use nylon or other synthetic stings as these are too slippery for candy crystal growth. Coarse cotton twine works best, providing locations for crystal growth to begin (these are called nucleation sites).