It sounds like you are having trouble growing root crops (garlic, onions and potatoes are more like tubers or bulbs) and my guess is that when you seed small seeds in spring the seedligs will suffer if your soil is too sandy and dry or most likely too heavy and wet.  Carrots and beets mush have well drained soil. By the time you plant heat loving tomatoes, peppers and cucumbers the soil has dried out a bit because of the later planting date so they thrive. Maybe you can try raised beds for spring planting or grow the early crops in large containers. Dont' give up, Keep Growing, Marianne Binetti