Lots of growth above ground, but nothing below…..beets, radishes, carrots, etc
Everything grows quite nicely, but the root vegetables just grow huge leaves above ground and nothing below...radishes, beets, carrots are wimpy, onions seam to be struggling....but above ground, they look great.
Mike, without knowing more about your soil and other growing conditions, I can only guess that the problem is one or both of these factors:
1. soil tilth is the physical condition of the soil, including is it loose and friable with good organic matter content, or is it tight and compacted with impenetrable clayey texture. Root vegetables in particular need good tilth. Soil improvements may be needed to create better conditions for you root veggies to grow below soil grade.
2. Soil nutrient availability and balance. Fertilization, products and timing are important. Fast release chemical Nitrogen fertilizer or manures can cause excessive vegetative growth at the expense of the root/tuber development. A balanced, slow release organic fertilizer is best. Bone meal or fish bone meal provides Phosphorus which is needed for root crop development. Adequate soil organic matter is important, which is best provided by incorporating compost into the soil before planting. After planting, a layer of mulch is the best you can do.
This article on beets has some general information that is applicable to other root vegetables too: