Whoever thought of raised beds for gardening was a genius. Raised beds are easier on the back, neater and are a highly productive method for growing vegetables, flowers and herbs. Root crops like carrots and potatoes like the growing medium used in a raised bed because it doesn't pack down, and the vegetable is allowed to expand easily, producing larger individual vegetables.
Loosen the soil in the raised bed with a garden fork. If the soil has packed down from previous years' use, add soil-less planting medium to give the soil more aeration, saving some to cover the seeds. Since soil-less medium doesn't have the nutrients needed for maximum growth, you should also add either 10-10-10 fertilizer or an ample application of compost. Once the soil has been adequately mixed, smooth over the top without packing it down.
String the twine from one side of the raised bed straight over to the other side, and tack on both sides. This is your seeding guide. Use a hand rake and slightly press the tines into the soil along the seedling guide line. Since raised beds are generally weed free and you don't need a place to walk between the rows, you can plant your rows 4 to 5 inches apart. Make seedling guides on half the bed, plant the seeds as below, and then do the other half. Doing it in this manner keeps the twine out of your way while you are planting.
Tear open the seed packet, and pour the tiny seeds into your nondominant hand. Use the fingers of your dominant hand to transfer the seeds into the indentations along the seed guide line.
Remove all the seed guide lines.
Place the saved soil-less medium evenly over the entire raised bed, 1/4 inch deep.
Water the raised bed, preferably with the sprinkler setting on a garden hose. Until the seeds germinate and seedlings appear, keep the soil damp.
Thin out the seedlings after they have grown at least 3 inches tall. Each carrot plant will need approximately an inch of space to grow straight and not crowd out other plants.