Carrots require deep sandy loam to produce long roots. If your soil is clay-like, you will need to amend it with a good amount of compost, Planting Mix, or Loam Builder. You may want to plant dwarf varieties such as Danver’ s Half Long if your soil is not crumbly and loose at a 1 foot depth.
Apply E.B. Stone All Purpose Organic (5-5-5) fertilizer and Kelp Meal (1-0-1) when the soil is prepared. Carrots love potassium which is the third fertilizer number on the box. Too much nitrogen will produce roots that have many hairy roots and fork so don’t feed regularly after they emerge as you would leafy vegetables. The seeds should be planted very shallowly as they require some UV light to germinate.
Sometimes it is best to sprinkle the seeds on the prepared surface and dust them with no more than ¼“ of potting soil or fine vermiculite. It can take up to 14 days for germination to occur, so be patient. You can mark your row by planting fast germinating radish seeds in front or at the sides. Once your seeds sprout and produce the first true leaves, you can begin to thin them. The carrot thinnings and the baby carrots can be added to soups. Ultimately, you will want 1″ between carrots.
Keep carrots well watered. Do not let the soil dry between irrigations. This will cause cracking and corkiness in roots and reduced size.