Carrots and cukes are at the opposite end of the planting curve. Carrots need to be planted very early while the weather is still cool. It may take them three weeks to come up. If the soil dries out or gets too warm, they won't germinate. I suggest planting 1/4 inch deep, then cover with a board. Peek under now and then and when you see some coming move the board. This holds the moisture.
Cucumbers, on the other hand, like warm weather and should be planted when all danger of frost is past and the ground is warm. They should come up in a week. If the ground is too cool or wet, the seed will usually just rot. Plant about half an inch deep and keep the ground damp. If the ground dries below where the seed is, you will lose it.
You can also pre germinate cukes. Soak them in water over night, then put them in a covered dish on a damp paper towel for two days, then plant them.
Gardening at 5000 feet elevation, zone 4/5 Northern Utah, Frost free from May 25 to September 8 +/-